[FFmpeg-devel] [PATCH 1/2] avcodec/jpeg2000dec: Add support for placeholder passes, CAP, and CPF markers

WATANABE Osamu owatanab at es.takushoku-u.ac.jp
Sat Jun 15 10:55:16 EEST 2024


Hi Pierre,

Here is the list of supported J2K reference codestreams.
p0_10.j2k
p1_01.j2k
p1_02.j2k
p1_03.j2k
p1_04.j2k
p1_05.j2k
p1_06.j2k
ds0_hm_15_b8.j2k
ds0_ht_02_b11.j2k
ds0_ht_02_b12.j2k
ds0_ht_03_b11.j2k
ds0_ht_03_b14.j2k
ds0_ht_04_b11.j2k
ds0_ht_04_b12.j2k
ds0_ht_05_b11.j2k
ds0_ht_05_b12.j2k
ds0_ht_07_b11.j2k
ds0_ht_07_b15.j2k
ds0_ht_07_b16.j2k
ds0_ht_08_b11.j2k
ds0_ht_08_b15.j2k
ds0_ht_08_b16.j2k
ds0_ht_09_b11.j2k
ds0_ht_10_b11.j2k
ds0_ht_11_b10.j2k
ds0_ht_12_b11.j2k
ds0_ht_14_b11.j2k
ds0_ht_15_b11.j2k
ds0_ht_15_b14.j2k
ds0_ht_16_b11.j2k
ds1_ht_01_b11.j2k
ds1_ht_01_b12.j2k
ds1_ht_02_b11.j2k
ds1_ht_02_b12.j2k
ds1_ht_03_b11.j2k
ds1_ht_03_b12.j2k
ds1_ht_04_b9.j2k
ds1_ht_05_b11.j2k
ds1_ht_06_b11.j2k
hifi_ht1_02.j2k
hifi_p1_02.j2k

FYI - the following codestreams are excluded from the list due to their unsupported pixel format in FFMPEG.
p0_06.j2k
p0_13.j2k
p1_07.j2k
ds0_ht_06_b11.j2k
ds0_ht_06_b15.j2k
ds0_ht_06_b18.j2k
ds0_hm_06_b11.j2k
ds0_hm_06_b18.j2k
ds0_ht_13_b11.j2k
ds1_ht_07_b11.j2k

Separate color component should be decodable and I can provide them if necessary.

Best,
Osau

> On Jun 15, 2024, at 15:00, Pierre-Anthony Lemieux <pal at sandflow.com> wrote:
> 
> Hi Osamu,
> 
> Can you provide the list of J2K reference codestreams that this code
> allows FFMPEG to support -- not including those already supported [1]?
> 
> [1] https://github.com/FFmpeg/FFmpeg/blob/master/tests/fate/jpeg2000.mak
> 
> Best,
> 
> -- Pierre
> 
> On Fri, Jun 14, 2024 at 8:15?PM Osamu Watanabe
> <owatanab at es.takushoku-u.ac.jp> wrote:
>> 
>> Signed-off-by: Osamu Watanabe <owatanab at es.takushoku-u.ac.jp>
>> ---
>> libavcodec/jpeg2000.h      |  10 +
>> libavcodec/jpeg2000dec.c   | 454 ++++++++++++++++++++++++++++++-------
>> libavcodec/jpeg2000dec.h   |   7 +
>> libavcodec/jpeg2000htdec.c | 225 ++++++++++--------
>> libavcodec/jpeg2000htdec.h |   2 +-
>> 5 files changed, 518 insertions(+), 180 deletions(-)
>> 
>> diff --git a/libavcodec/jpeg2000.h b/libavcodec/jpeg2000.h
>> index d004c08f10..93221d90ca 100644
>> --- a/libavcodec/jpeg2000.h
>> +++ b/libavcodec/jpeg2000.h
>> @@ -37,12 +37,14 @@
>> 
>> enum Jpeg2000Markers {
>>     JPEG2000_SOC = 0xff4f, // start of codestream
>> +    JPEG2000_CAP = 0xff50, // extended capabilities
>>     JPEG2000_SIZ = 0xff51, // image and tile size
>>     JPEG2000_COD,          // coding style default
>>     JPEG2000_COC,          // coding style component
>>     JPEG2000_TLM = 0xff55, // tile-part length, main header
>>     JPEG2000_PLM = 0xff57, // packet length, main header
>>     JPEG2000_PLT,          // packet length, tile-part header
>> +    JPEG2000_CPF,          // corresponding profile
>>     JPEG2000_QCD = 0xff5c, // quantization default
>>     JPEG2000_QCC,          // quantization component
>>     JPEG2000_RGN,          // region of interest
>> @@ -58,6 +60,12 @@ enum Jpeg2000Markers {
>>     JPEG2000_EOC = 0xffd9, // end of codestream
>> };
>> 
>> +enum JPEG2000_Ccap15_b14_15_params {
>> +    HTJ2K_HTONLY = 0,      // HTONLY, bit 14 and 15 are 0
>> +    HTJ2K_HTDECLARED,      // HTDECLARED, bit 14 = 1 and bit 15 = 0
>> +    HTJ2K_MIXED = 3,       // MIXED, bit 14 and 15 are 1
>> +};
>> +
>> #define JPEG2000_SOP_FIXED_BYTES 0xFF910004
>> #define JPEG2000_SOP_BYTE_LENGTH 6
>> 
>> @@ -192,6 +200,8 @@ typedef struct Jpeg2000Cblk {
>>     /* specific to HT code-blocks */
>>     int zbp;
>>     int pass_lengths[2];
>> +    uint8_t modes; // copy of SPcod/SPcoc field to parse HT-MIXED mode
>> +    uint8_t ht_plhd; // are we looking for HT placeholder passes?
>> } Jpeg2000Cblk; // code block
>> 
>> typedef struct Jpeg2000Prec {
>> diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
>> index d15502a527..d299c67cc7 100644
>> --- a/libavcodec/jpeg2000dec.c
>> +++ b/libavcodec/jpeg2000dec.c
>> @@ -54,6 +54,15 @@
>> #define HAD_COC 0x01
>> #define HAD_QCC 0x02
>> 
>> +// Values of flag for placeholder passes
>> +enum HT_PLHD_STATUS {
>> +    HT_PLHD_OFF,
>> +    HT_PLHD_ON
>> +};
>> +
>> +#define HT_MIXED 0x80 // bit 7 of SPcod/SPcoc
>> +
>> +
>> /* get_bits functions for JPEG2000 packet bitstream
>>  * It is a get_bit function with a bit-stuffing routine. If the value of the
>>  * byte is 0xFF, the next byte includes an extra zero bit stuffed into the MSB.
>> @@ -382,6 +391,9 @@ static int get_siz(Jpeg2000DecoderContext *s)
>>         } else if (ncomponents == 1 && s->precision == 8) {
>>             s->avctx->pix_fmt = AV_PIX_FMT_GRAY8;
>>             i = 0;
>> +        } else if (ncomponents == 1 && s->precision == 12) {
>> +            s->avctx->pix_fmt = AV_PIX_FMT_GRAY16LE;
>> +            i = 0;
>>         }
>>     }
>> 
>> @@ -408,6 +420,73 @@ static int get_siz(Jpeg2000DecoderContext *s)
>>     s->avctx->bits_per_raw_sample = s->precision;
>>     return 0;
>> }
>> +/* get extended capabilities (CAP) marker segment */
>> +static int get_cap(Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *c)
>> +{
>> +    uint32_t Pcap;
>> +    uint16_t Ccap_i[32] = { 0 };
>> +    uint16_t Ccap_15;
>> +    uint8_t P;
>> +
>> +    if (bytestream2_get_bytes_left(&s->g) < 6) {
>> +        av_log(s->avctx, AV_LOG_ERROR, "Insufficient space for CAP\n");
>> +        return AVERROR_INVALIDDATA;
>> +    }
>> +
>> +    Pcap = bytestream2_get_be32u(&s->g);
>> +    s->isHT = (Pcap >> (31 - (15 - 1))) & 1;
>> +    for (int i = 0; i < 32; i++) {
>> +        if ((Pcap >> (31 - i)) & 1)
>> +            Ccap_i[i] = bytestream2_get_be16u(&s->g);
>> +    }
>> +    Ccap_15 = Ccap_i[14];
>> +    if (s->isHT == 1) {
>> +    av_log(s->avctx, AV_LOG_INFO, "This is an HTJ2K codestream.\n");
>> +    // Bits 14-15
>> +    switch ((Ccap_15 >> 14) & 0x3) {
>> +        case 0x3:
>> +            s->Ccap15_b14_15 = HTJ2K_MIXED;
>> +            break;
>> +        case 0x1:
>> +            s->Ccap15_b14_15 = HTJ2K_HTDECLARED;
>> +            break;
>> +        case 0x0:
>> +            s->Ccap15_b14_15 = HTJ2K_HTONLY;
>> +            break;
>> +        default:
>> +                av_log(s->avctx, AV_LOG_ERROR, "Unknown CCap value.\n");
>> +            return AVERROR(EINVAL);
>> +            break;
>> +    }
>> +    // Bit 13
>> +    if ((Ccap_15 >> 13) & 1) {
>> +        av_log(s->avctx, AV_LOG_ERROR, "MULTIHT set is not supported.\n");
>> +        return AVERROR_PATCHWELCOME;
>> +    }
>> +    // Bit 12
>> +    s->Ccap15_b12 = (Ccap_15 >> 12) & 1;
>> +    // Bit 11
>> +    s->Ccap15_b11 = (Ccap_15 >> 11) & 1;
>> +    // Bit 5
>> +    s->Ccap15_b05 = (Ccap_15 >> 5) & 1;
>> +    // Bit 0-4
>> +    P = Ccap_15 & 0x1F;
>> +    if (!P)
>> +        s->HT_MAGB = 8;
>> +    else if (P < 20)
>> +        s->HT_MAGB = P + 8;
>> +    else if (P < 31)
>> +        s->HT_MAGB = 4 * (P - 19) + 27;
>> +    else
>> +        s->HT_MAGB = 74;
>> +
>> +    if (s->HT_MAGB > 31) {
>> +            av_log(s->avctx, AV_LOG_ERROR, "Available internal precision is exceeded (MAGB> 31).\n");
>> +        return AVERROR_PATCHWELCOME;
>> +    }
>> +    }
>> +    return 0;
>> +}
>> 
>> /* get common part for COD and COC segments */
>> static int get_cox(Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *c)
>> @@ -802,6 +881,15 @@ static int read_crg(Jpeg2000DecoderContext *s, int n)
>>     bytestream2_skip(&s->g, n - 2);
>>     return 0;
>> }
>> +
>> +static int read_cpf(Jpeg2000DecoderContext *s, int n)
>> +{
>> +    if (bytestream2_get_bytes_left(&s->g) < (n - 2))
>> +        return AVERROR_INVALIDDATA;
>> +    bytestream2_skip(&s->g, n - 2);
>> +    return 0;
>> +}
>> +
>> /* Tile-part lengths: see ISO 15444-1:2002, section A.7.1
>>  * Used to know the number of tile parts and lengths.
>>  * There may be multiple TLMs in the header.
>> @@ -965,6 +1053,10 @@ static int init_tile(Jpeg2000DecoderContext *s, int tileno)
>>             comp->roi_shift = s->roi_shift[compno];
>>         if (!codsty->init)
>>             return AVERROR_INVALIDDATA;
>> +        if (s->isHT && (!s->Ccap15_b05) && (!codsty->transform))
>> +            av_log(s->avctx, AV_LOG_WARNING, "Transformation = 0 (lossy DWT) is found in HTREV HT set\n");
>> +        if (s->isHT && s->Ccap15_b14_15 != (codsty->cblk_style >> 6) && s->Ccap15_b14_15 != HTJ2K_HTONLY)
>> +            av_log(s->avctx, AV_LOG_WARNING, "SPcod/SPcoc value does not match bit 14-15 values of Ccap15\n");
>>         if (ret = ff_jpeg2000_init_component(comp, codsty, qntsty,
>>                                              s->cbps[compno], s->cdx[compno],
>>                                              s->cdy[compno], s->avctx))
>> @@ -1067,100 +1159,275 @@ static int jpeg2000_decode_packet(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile,
>>             int incl, newpasses, llen;
>>             void *tmp;
>> 
>> -            if (cblk->npasses)
>> -                incl = get_bits(s, 1);
>> -            else
>> +            if (!cblk->incl) {
>> +                incl = 0;
>> +                cblk->modes = codsty->cblk_style;
>> +                if (cblk->modes >= JPEG2000_CTSY_HTJ2K_F)
>> +                    cblk->ht_plhd = HT_PLHD_ON;
>> +                if (layno > 0)
>> +                    incl = tag_tree_decode(s, prec->cblkincl + cblkno, 0 + 1) == 0;
>>                 incl = tag_tree_decode(s, prec->cblkincl + cblkno, layno + 1) == layno;
>> -            if (!incl)
>> -                continue;
>> -            else if (incl < 0)
>> -                return incl;
>> -
>> -            if (!cblk->npasses) {
>> -                int zbp = tag_tree_decode(s, prec->zerobits + cblkno, 100);
>> -                int v = expn[bandno] + numgbits - 1 - zbp;
>> 
>> -                if (v < 0 || v > 30) {
>> -                    av_log(s->avctx, AV_LOG_ERROR,
>> -                           "nonzerobits %d invalid or unsupported\n", v);
>> -                    return AVERROR_INVALIDDATA;
>> +                if (incl) {
>> +                    int zbp = tag_tree_decode(s, prec->zerobits + cblkno, 100);
>> +                    int v = expn[bandno] + numgbits - 1 - (zbp - tile->comp->roi_shift);
>> +                    if (v < 0 || v > 30) {
>> +                        av_log(s->avctx, AV_LOG_ERROR,
>> +                               "nonzerobits %d invalid or unsupported\n", v);
>> +                        return AVERROR_INVALIDDATA;
>> +                    }
>> +                    cblk->incl = 1;
>> +                    cblk->nonzerobits = v;
>> +                    cblk->zbp = zbp;
>> +                    cblk->lblock = 3;
>>                 }
>> -                cblk->zbp = zbp;
>> -                cblk->nonzerobits = v;
>> -            }
>> -            if ((newpasses = getnpasses(s)) < 0)
>> -                return newpasses;
>> -            av_assert2(newpasses > 0);
>> -            if (cblk->npasses + newpasses >= JPEG2000_MAX_PASSES) {
>> -                avpriv_request_sample(s->avctx, "Too many passes");
>> -                return AVERROR_PATCHWELCOME;
>> -            }
>> -            if ((llen = getlblockinc(s)) < 0)
>> -                return llen;
>> -            if (cblk->lblock + llen + av_log2(newpasses) > 16) {
>> -                avpriv_request_sample(s->avctx,
>> -                                      "Block with length beyond 16 bits");
>> -                return AVERROR_PATCHWELCOME;
>> +            } else {
>> +                incl = get_bits(s, 1);
>>             }
>> 
>> -            cblk->lblock += llen;
>> -
>> -            cblk->nb_lengthinc = 0;
>> -            cblk->nb_terminationsinc = 0;
>> -            av_free(cblk->lengthinc);
>> -            cblk->lengthinc = av_calloc(newpasses, sizeof(*cblk->lengthinc));
>> -            if (!cblk->lengthinc)
>> -                return AVERROR(ENOMEM);
>> -            tmp = av_realloc_array(cblk->data_start, cblk->nb_terminations + newpasses + 1, sizeof(*cblk->data_start));
>> -            if (!tmp)
>> -                return AVERROR(ENOMEM);
>> -            cblk->data_start = tmp;
>> -            do {
>> -                int newpasses1 = 0;
>> -
>> -                while (newpasses1 < newpasses) {
>> -                    newpasses1 ++;
>> -                    if (needs_termination(codsty->cblk_style, cblk->npasses + newpasses1 - 1)) {
>> -                        cblk->nb_terminationsinc ++;
>> -                        break;
>> +            if (incl) {
>> +                uint8_t bypass_term_threshold = 0;
>> +                uint8_t bits_to_read = 0;
>> +                uint32_t segment_bytes = 0;
>> +                int32_t segment_passes = 0;
>> +                uint8_t next_segment_passes = 0;
>> +                int32_t href_passes, pass_bound;
>> +                uint32_t tmp_length = 0;
>> +
>> +                if ((newpasses = getnpasses(s)) <= 0)
>> +                    return newpasses;
>> +                if (cblk->npasses + newpasses >= JPEG2000_MAX_PASSES) {
>> +                    avpriv_request_sample(s->avctx, "Too many passes");
>> +                    return AVERROR_PATCHWELCOME;
>> +                }
>> +                if ((llen = getlblockinc(s)) < 0)
>> +                    return llen;
>> +                if (cblk->lblock + llen + av_log2(newpasses) > 16) {
>> +                    avpriv_request_sample(s->avctx,
>> +                                          "Block with length beyond 16 bits");
>> +                    return AVERROR_PATCHWELCOME;
>> +                }
>> +                cblk->nb_lengthinc = 0;
>> +                cblk->nb_terminationsinc = 0;
>> +                av_free(cblk->lengthinc);
>> +                cblk->lengthinc = av_calloc(newpasses, sizeof(*cblk->lengthinc));
>> +                if (!cblk->lengthinc)
>> +                    return AVERROR(ENOMEM);
>> +                tmp = av_realloc_array(cblk->data_start, cblk->nb_terminations + newpasses + 1,
>> +                                       sizeof(*cblk->data_start));
>> +                if (!tmp)
>> +                    return AVERROR(ENOMEM);
>> +                cblk->data_start = tmp;
>> +                cblk->lblock += llen;
>> +
>> +                if (cblk->ht_plhd) {
>> +                    href_passes = (cblk->npasses + newpasses - 1) % 3;
>> +                    segment_passes = newpasses - href_passes;
>> +                    pass_bound = 2;
>> +                    bits_to_read = cblk->lblock;
>> +                    if (segment_passes < 1) {
>> +                        // No possible HT Cleanup pass here; may have placeholder passes
>> +                        // or an original J2K block bit-stream (in MIXED mode).
>> +                        segment_passes = newpasses;
>> +                        while (pass_bound <= segment_passes) {
>> +                            bits_to_read++;
>> +                            pass_bound += pass_bound;
>> +                        }
>> +                        segment_bytes = get_bits(s, bits_to_read);
>> +                        if (segment_bytes) {
>> +                            if (cblk->modes & HT_MIXED) {
>> +                                cblk->ht_plhd = HT_PLHD_OFF;
>> +                                cblk->modes &= (uint8_t) (~(JPEG2000_CTSY_HTJ2K_F));
>> +                            }
>> +                            else {
>> +                                av_log(s->avctx, AV_LOG_WARNING, "Length information for a HT-codeblock is invalid\n");
>> +                            }
>> +                        }
>> +                    } else {
>> +                        while (pass_bound <= segment_passes) {
>> +                            bits_to_read++;
>> +                            pass_bound += pass_bound;
>> +                        }
>> +                        segment_bytes = get_bits(s, bits_to_read);
>> +                        if (segment_bytes) {
>> +                            // No more placeholder passes
>> +                            if (!(cblk->modes & HT_MIXED)) {
>> +                                // Must be the first HT Cleanup pass
>> +                                if (segment_bytes < 2)
>> +                                    av_log(s->avctx, AV_LOG_WARNING, "Length information for a HT-codeblock is invalid\n");
>> +                                next_segment_passes = 2;
>> +                                cblk->ht_plhd = HT_PLHD_OFF;
>> +                                // Write length information for HT CleanUp segment
>> +                                cblk->pass_lengths[0] = segment_bytes;
>> +                            } else if (cblk->lblock > 3 && segment_bytes > 1
>> +                                       && (segment_bytes >> (bits_to_read - 1)) == 0) {
>> +                                // Must be the first HT Cleanup pass, since length MSB is 0
>> +                                next_segment_passes = 2;
>> +                                cblk->ht_plhd = HT_PLHD_OFF;
>> +                                // Write length information for HT CleanUp segment
>> +                                cblk->pass_lengths[0] = segment_bytes;
>> +                            } else {
>> +                                // Must have an original (non-HT) block coding pass
>> +                                cblk->modes &= (uint8_t) (~(JPEG2000_CTSY_HTJ2K_F));
>> +                                cblk->ht_plhd = HT_PLHD_OFF;
>> +                                segment_passes = newpasses;
>> +                                while (pass_bound <= segment_passes) {
>> +                                    bits_to_read++;
>> +                                    pass_bound += pass_bound;
>> +                                    segment_bytes <<= 1;
>> +                                    segment_bytes += get_bits(s, 1);
>> +                                }
>> +                            }
>> +                        } else {
>> +                            // Probably parsing placeholder passes, but we need to read an
>> +                            // extra length bit to verify this, since prior to the first
>> +                            // HT Cleanup pass, the number of length bits read for a
>> +                            // contributing code-block is dependent on the number of passes
>> +                            // being included, as if it were a non-HT code-block.
>> +                            segment_passes = newpasses;
>> +                            if (pass_bound <= segment_passes) {
>> +                                while (1) {
>> +                                    bits_to_read++;
>> +                                    pass_bound += pass_bound;
>> +                                    segment_bytes <<= 1;
>> +                                    segment_bytes += get_bits(s, 1);
>> +                                    if (pass_bound > segment_passes)
>> +                                        break;
>> +                                }
>> +                                if (segment_bytes) {
>> +                                    if (cblk->modes & HT_MIXED) {
>> +                                        cblk->modes &= (uint8_t) (~(JPEG2000_CTSY_HTJ2K_F));
>> +                                        cblk->ht_plhd = HT_PLHD_OFF;
>> +                                    } else {
>> +                                        av_log(s->avctx, AV_LOG_WARNING, "Length information for a HT-codeblock is invalid\n");
>> +                                    }
>> +                                }
>> +                            }
>> +                        }
>>                     }
>> +                } else if (cblk->modes & JPEG2000_CTSY_HTJ2K_F) {
>> +                    // Quality layer commences with a non-initial HT coding pass
>> +                    if(bits_to_read != 0)
>> +                        av_log(s->avctx, AV_LOG_WARNING, "Length information for a HT-codeblock is invalid\n");
>> +                    segment_passes = cblk->npasses % 3;
>> +                    if (segment_passes == 0) {
>> +                        // newpasses is a HT Cleanup pass; next segment has refinement passes
>> +                        segment_passes = 1;
>> +                        next_segment_passes = 2;
>> +                        if (segment_bytes == 1)
>> +                            av_log(s->avctx, AV_LOG_WARNING, "Length information for a HT-codeblock is invalid\n");
>> +                    } else {
>> +                        // newpasses = 1 means npasses is HT SigProp; 2 means newpasses is
>> +                        // HT MagRef pass
>> +                        segment_passes = newpasses > 1 ? 3 - segment_passes : 1;
>> +                        next_segment_passes = 1;
>> +                        bits_to_read = av_log2(segment_passes);
>> +                    }
>> +                    bits_to_read = (uint8_t) (bits_to_read + cblk->lblock);
>> +                    segment_bytes = get_bits(s, bits_to_read);
>> +                    // Write length information for HT Refinment segment
>> +                    cblk->pass_lengths[1] += segment_bytes;
>> +                } else if (!(cblk->modes & (JPEG2000_CBLK_TERMALL | JPEG2000_CBLK_BYPASS))) {
>> +                    // Common case for non-HT code-blocks; we have only one segment
>> +                    bits_to_read = (uint8_t) cblk->lblock + av_log2((uint8_t) newpasses);
>> +                    segment_bytes = get_bits(s, bits_to_read);
>> +                    segment_passes = newpasses;
>> +                } else if (cblk->modes & JPEG2000_CBLK_TERMALL) {
>> +                    // RESTART MODE
>> +                    bits_to_read = cblk->lblock;
>> +                    segment_bytes = get_bits(s, bits_to_read);
>> +                    segment_passes = 1;
>> +                    next_segment_passes = 1;
>> +                    cblk->nb_terminationsinc++;
>> +                } else {
>> +                    // BYPASS MODE
>> +                    bypass_term_threshold = 10;
>> +                    if(bits_to_read != 0)
>> +                        av_log(s->avctx, AV_LOG_WARNING, "Length information for a codeblock is invalid\n");
>> +                    if (cblk->npasses < bypass_term_threshold) {
>> +                        // May have from 1 to 10 uninterrupted passes before 1st RAW SigProp
>> +                        segment_passes = bypass_term_threshold - cblk->npasses;
>> +                        if (segment_passes > newpasses)
>> +                            segment_passes = newpasses;
>> +                        while ((2 << bits_to_read) <= segment_passes)
>> +                            bits_to_read++;
>> +                        next_segment_passes = 2;
>> +                    } else if ((cblk->npasses - bypass_term_threshold) % 3 < 2) {
>> +                        // 0 means newpasses is a RAW SigProp; 1 means newpasses is a RAW MagRef pass
>> +                        segment_passes = newpasses > 1 ? 2 - (cblk->npasses - bypass_term_threshold) % 3 : 1;
>> +                        bits_to_read = av_log2(segment_passes);
>> +                        next_segment_passes = 1;
>> +                    } else {
>> +                        // newpasses is an isolated Cleanup pass that precedes a RAW SigProp pass
>> +                        segment_passes = 1;
>> +                        next_segment_passes = 2;
>> +                    }
>> +                    bits_to_read = (uint8_t) (bits_to_read + cblk->lblock);
>> +                    segment_bytes = get_bits(s, bits_to_read);
>>                 }
>> -
>> -                if (newpasses > 1 && (codsty->cblk_style & JPEG2000_CTSY_HTJ2K_F)) {
>> -                    // Retrieve pass lengths for each pass
>> -                    int href_passes =  (cblk->npasses + newpasses - 1) % 3;
>> -                    int eb = av_log2(newpasses - href_passes);
>> -                    int extra_bit = newpasses > 2 ? 1 : 0;
>> -                    if ((ret = get_bits(s, llen + eb + 3)) < 0)
>> -                        return ret;
>> -                    cblk->pass_lengths[0] = ret;
>> -                    if ((ret = get_bits(s, llen + 3 + extra_bit)) < 0)
>> -                        return ret;
>> -                    cblk->pass_lengths[1] = ret;
>> -                    ret = cblk->pass_lengths[0] + cblk->pass_lengths[1];
>> +                // Update cblk->npasses and write length information
>> +                cblk->npasses = (uint8_t) (cblk->npasses + segment_passes);
>> +                cblk->lengthinc[cblk->nb_lengthinc++] = segment_bytes;
>> +
>> +                if ((cblk->modes & JPEG2000_CTSY_HTJ2K_F) && cblk->ht_plhd == HT_PLHD_OFF) {
>> +                    newpasses -= (uint8_t) segment_passes;
>> +                    while (newpasses > 0) {
>> +                        segment_passes = newpasses > 1 ? next_segment_passes : 1;
>> +                        next_segment_passes = (uint8_t) (3 - next_segment_passes);
>> +                        bits_to_read = (uint8_t) (cblk->lblock + av_log2(segment_passes));
>> +                        segment_bytes = get_bits(s, bits_to_read);
>> +                        newpasses -= (uint8_t) (segment_passes);
>> +                        // This is a FAST Refinement pass
>> +                        // Write length information for HT Refinement segment
>> +                        cblk->pass_lengths[1] += segment_bytes;
>> +                        // Update cblk->npasses and write length information
>> +                        cblk->npasses = (uint8_t) (cblk->npasses + segment_passes);
>> +                        cblk->lengthinc[cblk->nb_lengthinc++] = segment_bytes;
>> +                    }
>>                 } else {
>> -                    if ((ret = get_bits(s, av_log2(newpasses1) + cblk->lblock)) < 0)
>> -                        return ret;
>> -                    cblk->pass_lengths[0] = ret;
>> +                    newpasses -= (uint8_t) (segment_passes);
>> +                    while (newpasses > 0) {
>> +                        if (bypass_term_threshold != 0) {
>> +                            segment_passes = newpasses > 1 ? next_segment_passes : 1;
>> +                            next_segment_passes = (uint8_t) (3 - next_segment_passes);
>> +                            bits_to_read = (uint8_t) (cblk->lblock + av_log2(segment_passes));
>> +                        } else {
>> +                            if ((cblk->modes & JPEG2000_CBLK_TERMALL) == 0)
>> +                                av_log(s->avctx, AV_LOG_WARNING, "Corrupted packet header is found.\n");
>> +                            segment_passes = 1;
>> +                            bits_to_read = cblk->lblock;
>> +                        }
>> +                        segment_bytes = get_bits(s, bits_to_read);
>> +                        newpasses -= (uint8_t) (segment_passes);
>> +
>> +                        // Update cblk->npasses and write length information
>> +                        cblk->npasses = (uint8_t) (cblk->npasses + segment_passes);
>> +                        cblk->lengthinc[cblk->nb_lengthinc++] = segment_bytes;
>> +                        cblk->nb_terminationsinc++;
>> +                    }
>>                 }
>> -                if (ret > cblk->data_allocated) {
>> -                    size_t new_size = FFMAX(2*cblk->data_allocated, ret);
>> +
>> +                for (int i = 0; i < cblk->nb_lengthinc; ++i)
>> +                    tmp_length = (tmp_length < cblk->lengthinc[i]) ? cblk->lengthinc[i] : tmp_length;
>> +
>> +                if (tmp_length > cblk->data_allocated) {
>> +                    size_t new_size = FFMAX(2 * cblk->data_allocated, tmp_length);
>>                     void *new = av_realloc(cblk->data, new_size);
>>                     if (new) {
>>                         cblk->data = new;
>>                         cblk->data_allocated = new_size;
>>                     }
>>                 }
>> -                if (ret > cblk->data_allocated) {
>> +                if (tmp_length > cblk->data_allocated) {
>>                     avpriv_request_sample(s->avctx,
>>                                         "Block with lengthinc greater than %"SIZE_SPECIFIER"",
>>                                         cblk->data_allocated);
>>                     return AVERROR_PATCHWELCOME;
>>                 }
>> -                cblk->lengthinc[cblk->nb_lengthinc++] = ret;
>> -                cblk->npasses  += newpasses1;
>> -                newpasses -= newpasses1;
>> -            } while(newpasses);
>> +            } else {
>> +                // This codeblock has no contribution to the current packet
>> +                continue;
>> +            }
>>         }
>>     }
>>     jpeg2000_flush(s);
>> @@ -1695,7 +1962,7 @@ static int decode_cblk(const Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *cod
>>                        Jpeg2000T1Context *t1, Jpeg2000Cblk *cblk,
>>                        int width, int height, int bandpos, uint8_t roi_shift)
>> {
>> -    int passno = cblk->npasses, pass_t = 2, bpno = cblk->nonzerobits - 1 + roi_shift;
>> +    int passno = cblk->npasses, pass_t = 2, bpno = cblk->nonzerobits - 1;
>>     int pass_cnt = 0;
>>     int vert_causal_ctx_csty_symbol = codsty->cblk_style & JPEG2000_CBLK_VSC;
>>     int term_cnt = 0;
>> @@ -1909,7 +2176,7 @@ static inline int tile_codeblocks(const Jpeg2000DecoderContext *s, Jpeg2000Tile
>>                 Jpeg2000Band *band = rlevel->band + bandno;
>>                 int cblkno = 0, bandpos;
>>                 /* See Rec. ITU-T T.800, Equation E-2 */
>> -                int magp = quantsty->expn[subbandno] + quantsty->nguardbits - 1;
>> +                int M_b = quantsty->expn[subbandno] + quantsty->nguardbits - 1;
>> 
>>                 bandpos = bandno + (reslevelno > 0);
>> 
>> @@ -1917,8 +2184,8 @@ static inline int tile_codeblocks(const Jpeg2000DecoderContext *s, Jpeg2000Tile
>>                     band->coord[1][0] == band->coord[1][1])
>>                     continue;
>> 
>> -                if ((codsty->cblk_style & JPEG2000_CTSY_HTJ2K_F) && magp >= 31) {
>> -                    avpriv_request_sample(s->avctx, "JPEG2000_CTSY_HTJ2K_F and magp >= 31");
>> +                if ((codsty->cblk_style & JPEG2000_CTSY_HTJ2K_F) && M_b >= 31) {
>> +                    avpriv_request_sample(s->avctx, "JPEG2000_CTSY_HTJ2K_F and M_b >= 31");
>>                     return AVERROR_PATCHWELCOME;
>>                 }
>> 
>> @@ -1935,11 +2202,11 @@ static inline int tile_codeblocks(const Jpeg2000DecoderContext *s, Jpeg2000Tile
>> 
>>                         Jpeg2000Cblk *cblk = prec->cblk + cblkno;
>> 
>> -                        if (codsty->cblk_style & JPEG2000_CTSY_HTJ2K_F)
>> +                        if (cblk->modes & JPEG2000_CTSY_HTJ2K_F)
>>                             ret = ff_jpeg2000_decode_htj2k(s, codsty, &t1, cblk,
>>                                                            cblk->coord[0][1] - cblk->coord[0][0],
>>                                                            cblk->coord[1][1] - cblk->coord[1][0],
>> -                                                           magp, comp->roi_shift);
>> +                                                           M_b, comp->roi_shift);
>>                         else
>>                             ret = decode_cblk(s, codsty, &t1, cblk,
>>                                               cblk->coord[0][1] - cblk->coord[0][0],
>> @@ -2178,22 +2445,42 @@ static int jpeg2000_read_main_headers(Jpeg2000DecoderContext *s)
>>             if (!s->tile)
>>                 s->numXtiles = s->numYtiles = 0;
>>             break;
>> +        case JPEG2000_CAP:
>> +            if (!s->ncomponents) {
>> +                av_log(s->avctx, AV_LOG_WARNING, "CAP marker segment shall come after SIZ\n");
>> +            }
>> +            ret = get_cap(s, codsty);
>> +            break;
>>         case JPEG2000_COC:
>> +            if (s->in_tile_headers == 1 && s->isHT && (!s->Ccap15_b11))
>> +                av_log(s->avctx, AV_LOG_WARNING, "COC marker is found in HOMOGENEOUS HT set\n");
>>             ret = get_coc(s, codsty, properties);
>>             break;
>>         case JPEG2000_COD:
>> +            if (s->in_tile_headers == 1 && s->isHT && (!s->Ccap15_b11))
>> +                av_log(s->avctx, AV_LOG_WARNING, "COD marker is found in HOMOGENEOUS HT set\n");
>>             ret = get_cod(s, codsty, properties);
>>             break;
>>         case JPEG2000_RGN:
>> +            if (s->in_tile_headers == 1 && s->isHT && (!s->Ccap15_b11))
>> +                av_log(s->avctx, AV_LOG_WARNING, "RGB marker is found in HOMOGENEOUS HT set\n");
>>             ret = get_rgn(s, len);
>> +            if ((!s->Ccap15_b12) && s->isHT)
>> +                av_log(s->avctx, AV_LOG_WARNING, "RGN marker is found in RGNFREE HT set\n");
>>             break;
>>         case JPEG2000_QCC:
>> +            if (s->in_tile_headers == 1 && s->isHT && (!s->Ccap15_b11))
>> +                av_log(s->avctx, AV_LOG_WARNING, "QCC marker is found in HOMOGENEOUS HT set\n");
>>             ret = get_qcc(s, len, qntsty, properties);
>>             break;
>>         case JPEG2000_QCD:
>> +            if (s->in_tile_headers == 1 && s->isHT && (!s->Ccap15_b11))
>> +                av_log(s->avctx, AV_LOG_WARNING, "QCD marker is found in HOMOGENEOUS HT set\n");
>>             ret = get_qcd(s, len, qntsty, properties);
>>             break;
>>         case JPEG2000_POC:
>> +            if (s->in_tile_headers == 1 && s->isHT && (!s->Ccap15_b11))
>> +                av_log(s->avctx, AV_LOG_WARNING, "POC marker is found in HOMOGENEOUS HT set\n");
>>             ret = get_poc(s, len, poc);
>>             break;
>>         case JPEG2000_SOT:
>> @@ -2243,9 +2530,14 @@ static int jpeg2000_read_main_headers(Jpeg2000DecoderContext *s)
>>                        "Cannot have both PPT and PPM marker.\n");
>>                 return AVERROR_INVALIDDATA;
>>             }
>> -
>> +            if ((!s->Ccap15_b11) && s->isHT)
>> +                av_log(s->avctx, AV_LOG_WARNING, "PPT marker is found in HOMOGENEOUS HT set\n");
>>             ret = get_ppt(s, len);
>>             break;
>> +        case JPEG2000_CPF:
>> +            // Corresponding profile marker
>> +            ret = read_cpf(s, len);
>> +            break;
>>         default:
>>             av_log(s->avctx, AV_LOG_ERROR,
>>                    "unsupported marker 0x%.4"PRIX16" at pos 0x%X\n",
>> diff --git a/libavcodec/jpeg2000dec.h b/libavcodec/jpeg2000dec.h
>> index d0ca6e7a79..326a572722 100644
>> --- a/libavcodec/jpeg2000dec.h
>> +++ b/libavcodec/jpeg2000dec.h
>> @@ -112,6 +112,13 @@ typedef struct Jpeg2000DecoderContext {
>>     Jpeg2000Tile    *tile;
>>     Jpeg2000DSPContext dsp;
>> 
>> +    uint8_t         isHT; // HTJ2K?
>> +    uint8_t         Ccap15_b14_15; // HTONLY(= 0) or HTDECLARED(= 1) or MIXED(= 3) ?
>> +    uint8_t         Ccap15_b12; // RGNFREE(= 0) or RGN(= 1)?
>> +    uint8_t         Ccap15_b11; // HOMOGENEOUS(= 0) or HETEROGENEOUS(= 1) ?
>> +    uint8_t         Ccap15_b05; // HTREV(= 0) or HTIRV(= 1) ?
>> +    uint8_t         HT_MAGB; // MAGB value
>> +
>>     /*options parameters*/
>>     int             reduction_factor;
>> } Jpeg2000DecoderContext;
>> diff --git a/libavcodec/jpeg2000htdec.c b/libavcodec/jpeg2000htdec.c
>> index eba0936089..beb4a386b0 100644
>> --- a/libavcodec/jpeg2000htdec.c
>> +++ b/libavcodec/jpeg2000htdec.c
>> @@ -122,7 +122,7 @@ static void jpeg2000_init_mel(StateVars *s, uint32_t Pcup)
>> 
>> static void jpeg2000_init_mag_ref(StateVars *s, uint32_t Lref)
>> {
>> -    s->pos       = Lref - 2;
>> +    s->pos       = Lref - 1;
>>     s->bits      = 0;
>>     s->last      = 0xFF;
>>     s->tmp       = 0;
>> @@ -145,9 +145,10 @@ static void jpeg2000_init_mel_decoder(MelDecoderState *mel_state)
>> static int jpeg2000_bitbuf_refill_backwards(StateVars *buffer, const uint8_t *array)
>> {
>>     uint64_t tmp = 0;
>> -    int32_t position = buffer->pos - 4;
>>     uint32_t new_bits = 32;
>> 
>> +    buffer->last = array[buffer->pos + 1];
>> +
>>     if (buffer->bits_left >= 32)
>>         return 0; // enough data, no need to pull in more bits
>> 
>> @@ -157,9 +158,24 @@ static int jpeg2000_bitbuf_refill_backwards(StateVars *buffer, const uint8_t *ar
>>      *  the bottom most bits.
>>      */
>> 
>> -    for(int i = FFMAX(0, position + 1); i <= buffer->pos + 1; i++)
>> -        tmp = 256*tmp + array[i];
>> -
>> +    if (buffer->pos >= 3) {  // Common case; we have at least 4 bytes available
>> +         tmp = array[buffer->pos - 3];
>> +         tmp = (tmp << 8) | array[buffer->pos - 2];
>> +         tmp = (tmp << 8) | array[buffer->pos - 1];
>> +         tmp = (tmp << 8) | array[buffer->pos];
>> +         tmp = (tmp << 8) | buffer->last;  // For stuffing bit detection
>> +         buffer->pos -= 4;
>> +    } else {
>> +        if (buffer->pos >= 2)
>> +            tmp = array[buffer->pos - 2];
>> +        if (buffer->pos >= 1)
>> +            tmp = (tmp << 8) | array[buffer->pos - 1];
>> +        if (buffer->pos >= 0)
>> +            tmp = (tmp << 8) | array[buffer->pos];
>> +        buffer->pos = 0;
>> +        tmp = (tmp << 8) | buffer->last;  // For stuffing bit detection
>> +    }
>> +    // Now remove any stuffing bits, shifting things down as we go
>>     if ((tmp & 0x7FFF000000) > 0x7F8F000000) {
>>         tmp &= 0x7FFFFFFFFF;
>>         new_bits--;
>> @@ -176,13 +192,11 @@ static int jpeg2000_bitbuf_refill_backwards(StateVars *buffer, const uint8_t *ar
>>         tmp = (tmp & 0x0000007FFF) + ((tmp & 0xFFFFFF0000) >> 1);
>>         new_bits--;
>>     }
>> -
>> -    tmp >>= 8; // Remove temporary byte loaded
>> +    tmp >>= 8;  // Shifts away the extra byte we imported
>> 
>>     /* Add bits to the MSB of the bit buffer */
>>     buffer->bit_buf |= tmp << buffer->bits_left;
>>     buffer->bits_left += new_bits;
>> -    buffer->pos = FFMAX(0, position);
>>     return 0;
>> }
>> 
>> @@ -406,6 +420,7 @@ static void recover_mag_sgn(StateVars *mag_sgn, uint8_t pos, uint16_t q, int32_t
>>             E[n] = 32 - ff_clz(v[pos][i] | 1);
>>             mu_n[n] = (v[pos][i] >> 1) + 1;
>>             mu_n[n] <<= pLSB;
>> +            mu_n[n] |= (1 << (pLSB - 1)); // Add 0.5 (reconstruction parameter = 1/2)
>>             mu_n[n] |= ((uint32_t) (v[pos][i] & 1)) << 31; // sign bit.
>>         }
>>     }
>> @@ -414,7 +429,7 @@ static void recover_mag_sgn(StateVars *mag_sgn, uint8_t pos, uint16_t q, int32_t
>> static int jpeg2000_import_bit(StateVars *stream, const uint8_t *array, uint32_t length)
>> {
>>     int cond = stream->pos < length;
>> -    int pos = FFMIN(stream->pos, length);
>> +    int pos = FFMIN(stream->pos, length - 1);
>>     if (stream->bits == 0) {
>>         stream->bits = (stream->tmp == 0xFF) ? 7 : 8;
>>         stream->pos += cond;
>> @@ -426,14 +441,22 @@ static int jpeg2000_import_bit(StateVars *stream, const uint8_t *array, uint32_t
>> 
>> static int jpeg2000_peek_bit(StateVars *stream, const uint8_t *array, uint32_t length)
>> {
>> +    uint8_t bit;
>> +
>>     if (stream->bits == 0) {
>> -        int cond = stream->pos < length;
>> -        int pos = FFMIN(stream->pos, length);
>> -        stream->bits = (stream->tmp == 0xFF) ? 7 : 8;
>> -        stream->pos += cond;
>> -        stream->tmp = cond ? array[pos] : 0xFF;
>> +        stream->bits = (stream->last == 0xFF) ? 7 : 8;
>> +        if (stream->pos < length) {
>> +            stream->tmp = array[stream->pos];
>> +            stream->pos++;
>> +        } else {
>> +            stream->tmp = 0;
>> +        }
>> +        stream->last = stream->tmp;
>>     }
>> -    return (stream->tmp >> stream->bits) & 1;
>> +    bit = stream->tmp & 1;
>> +    stream->tmp >>= 1;
>> +    stream->bits--;
>> +    return  bit;
>> }
>> 
>> static int jpeg2000_decode_mel_sym(MelDecoderState *mel_state,
>> @@ -994,66 +1017,63 @@ static void jpeg2000_calc_mbr(uint8_t *mbr, const uint16_t i, const uint16_t j,
>>                               const uint32_t mbr_info, uint8_t causal_cond,
>>                               uint8_t *block_states, int stride)
>> {
>> -    int local_mbr = 0;
>> -
>> -    local_mbr |= jpeg2000_get_state(i - 1, j - 1, stride, HT_SHIFT_SIGMA, block_states);
>> -    local_mbr |= jpeg2000_get_state(i - 1, j + 0, stride, HT_SHIFT_SIGMA, block_states);
>> -    local_mbr |= jpeg2000_get_state(i - 1, j + 1, stride, HT_SHIFT_SIGMA, block_states);
>> -
>> -    local_mbr |= jpeg2000_get_state(i + 0, j - 1, stride, HT_SHIFT_SIGMA, block_states);
>> -    local_mbr |= jpeg2000_get_state(i + 0, j + 1, stride, HT_SHIFT_SIGMA, block_states);
>> -
>> -    local_mbr |= jpeg2000_get_state(i + 1, j - 1, stride, HT_SHIFT_SIGMA, block_states) * causal_cond;
>> -    local_mbr |= jpeg2000_get_state(i + 1, j + 0, stride, HT_SHIFT_SIGMA, block_states) * causal_cond;
>> -    local_mbr |= jpeg2000_get_state(i + 1, j + 1, stride, HT_SHIFT_SIGMA, block_states) * causal_cond;
>> -
>> -    local_mbr |= jpeg2000_get_state(i - 1, j - 1, stride, HT_SHIFT_REF, block_states) *
>> -                 jpeg2000_get_state(i - 1, j - 1, stride, HT_SHIFT_SCAN, block_states);
>> -    local_mbr |= jpeg2000_get_state(i - 1, j + 0, stride, HT_SHIFT_REF, block_states) *
>> -                 jpeg2000_get_state(i - 1, j - 1, stride, HT_SHIFT_SCAN, block_states);
>> -    local_mbr |= jpeg2000_get_state(i - 1, j + 1, stride, HT_SHIFT_REF, block_states) *
>> -                 jpeg2000_get_state(i - 1, j + 1, stride, HT_SHIFT_SCAN, block_states);
>> -
>> -    local_mbr |= jpeg2000_get_state(i + 0, j - 1, stride, HT_SHIFT_REF, block_states) *
>> -                 jpeg2000_get_state(i + 0, j - 1, stride, HT_SHIFT_SCAN, block_states);
>> -    local_mbr |= jpeg2000_get_state(i + 0, j + 1, stride, HT_SHIFT_REF, block_states) *
>> -                 jpeg2000_get_state(i + 0, j + 1, stride, HT_SHIFT_SCAN, block_states);
>> -
>> -    local_mbr |= jpeg2000_get_state(i + 1, j - 1, stride, HT_SHIFT_REF, block_states) *
>> -                 jpeg2000_get_state(i + 1, j - 1, stride, HT_SHIFT_SCAN, block_states) * causal_cond;
>> -    local_mbr |= jpeg2000_get_state(i + 1, j + 0, stride, HT_SHIFT_REF, block_states) *
>> -                 jpeg2000_get_state(i + 1, j + 0, stride, HT_SHIFT_SCAN, block_states) * causal_cond;
>> -    local_mbr |= jpeg2000_get_state(i + 1, j + 1, stride, HT_SHIFT_REF, block_states) *
>> -                 jpeg2000_get_state(i + 1, j + 1, stride, HT_SHIFT_SCAN, block_states) * causal_cond;
>> -
>> -    *mbr |= local_mbr;
>> +    uint8_t *state_p0 = block_states + i * stride + j;
>> +    uint8_t *state_p1 = block_states + (i + 1) * stride + j;
>> +    uint8_t *state_p2 = block_states + (i + 2) * stride + j;
>> +
>> +    uint8_t mbr0 = state_p0[0] | state_p0[1] | state_p0[2];
>> +    uint8_t mbr1 = state_p1[0] | state_p1[2];
>> +    uint8_t mbr2 = state_p2[0] | state_p2[1] | state_p2[2];
>> +    *mbr  = mbr0 | mbr1 | (mbr2 & causal_cond);
>> +    *mbr |= (mbr0 >> HT_SHIFT_REF) & (mbr0 >> HT_SHIFT_SCAN);
>> +    *mbr |= (mbr1 >> HT_SHIFT_REF) & (mbr1 >> HT_SHIFT_SCAN);
>> +    *mbr |= (mbr2 >> HT_SHIFT_REF) & (mbr2 >> HT_SHIFT_SCAN) & causal_cond;
>> +    *mbr &= 1;
>> }
>> 
>> static void jpeg2000_process_stripes_block(StateVars *sig_prop, int i_s, int j_s,
>>                                            int width, int height, int stride, int pLSB,
>>                                            int32_t *sample_buf, uint8_t *block_states,
>> -                                           uint8_t *magref_segment, uint32_t magref_length)
>> +                                           uint8_t *magref_segment, uint32_t magref_length,
>> +                                           uint8_t is_causal)
>> {
>>     for (int j = j_s; j < j_s + width; j++) {
>>         uint32_t  mbr_info = 0;
>>         for (int i = i_s; i < i_s + height; i++) {
>> -            int modify_state, cond;
>> +            int modify_state;
>>             uint8_t bit;
>> -            uint8_t causal_cond = i != (i_s + height - 1);
>> +            uint8_t causal_cond = (is_causal == 0) || (i != (i_s + height - 1));
>>             int32_t *sp = &sample_buf[j + (i * (stride))];
>>             uint8_t mbr = 0;
>> 
>> -            if (jpeg2000_get_state(i, j, stride - 2, HT_SHIFT_SIGMA, block_states) == 0)
>> +            if (jpeg2000_get_state(i, j, stride, HT_SHIFT_SIGMA, block_states) == 0)
>>                 jpeg2000_calc_mbr(&mbr, i, j, mbr_info & 0x1EF, causal_cond, block_states, stride);
>>             mbr_info >>= 3;
>> -            cond = mbr != 0;
>> -            bit = jpeg2000_peek_bit(sig_prop, magref_segment, magref_length);
>> -            *sp |= (bit * cond) << pLSB;
>> -            sig_prop->bits -= cond;
>> -            modify_state = (((1 << HT_SHIFT_REF_IND) | (1 << HT_SHIFT_REF)) * cond) | 1 << HT_SHIFT_SCAN;
>> +
>> +            modify_state = block_states[(i + 1) * stride + (j + 1)];
>> +            modify_state |= 1 << HT_SHIFT_SCAN;
>> +            if (mbr != 0) {
>> +                modify_state |= 1 << HT_SHIFT_REF_IND;
>> +                bit = jpeg2000_peek_bit(sig_prop, magref_segment, magref_length);
>> +                modify_state |= bit << HT_SHIFT_REF;
>> +                *sp |= bit << pLSB;
>> +                *sp |= bit << (pLSB - 1); // Add 0.5 (reconstruction parameter = 1/2)
>> +            }
>>             jpeg2000_modify_state(i, j, stride, modify_state, block_states);
>>         }
>>     }
>> +    // decode sign
>> +    for (int j = j_s; j < j_s + width; j++) {
>> +        for (int i = i_s; i < i_s + height; i++) {
>> +            uint8_t bit;
>> +            int32_t *sp = &sample_buf[j + (i * (stride))];
>> +            uint8_t *state_p = block_states + (i + 1) * stride + (j + 1);
>> +            if ((state_p[0] >> HT_SHIFT_REF) & 1) {
>> +                bit = jpeg2000_peek_bit(sig_prop, magref_segment, magref_length);
>> +                *sp |= (int32_t)bit << 31;
>> +            }
>> +        }
>> +    }
>> }
>> 
>> /**
>> @@ -1074,6 +1094,7 @@ static void jpeg2000_decode_sigprop_segment(Jpeg2000Cblk *cblk, uint16_t width,
>> 
>>     int last_width;
>>     uint16_t i = 0, j = 0;
>> +    uint8_t is_causal = cblk->modes & JPEG2000_CBLK_VSC;
>> 
>>     jpeg2000_init_zero(&sp_dec);
>> 
>> @@ -1082,14 +1103,14 @@ static void jpeg2000_decode_sigprop_segment(Jpeg2000Cblk *cblk, uint16_t width,
>>         for (int n2 = 0; n2 < num_h_stripe; n2++) {
>>             jpeg2000_process_stripes_block(&sp_dec, i, j, b_width, b_height, stride,
>>                                            pLSB, sample_buf, block_states, magref_segment,
>> -                                           magref_length);
>> +                                           magref_length, is_causal);
>>             j += 4;
>>         }
>>         last_width = width % 4;
>>         if (last_width)
>>             jpeg2000_process_stripes_block(&sp_dec, i, j, last_width, b_height, stride,
>>                                            pLSB, sample_buf, block_states, magref_segment,
>> -                                           magref_length);
>> +                                           magref_length, is_causal);
>>         i += 4;
>>     }
>> 
>> @@ -1099,20 +1120,20 @@ static void jpeg2000_decode_sigprop_segment(Jpeg2000Cblk *cblk, uint16_t width,
>>     for (int n2 = 0; n2 < num_h_stripe; n2++) {
>>         jpeg2000_process_stripes_block(&sp_dec, i, j, b_width, b_height, stride,
>>                                        pLSB, sample_buf, block_states, magref_segment,
>> -                                       magref_length);
>> +                                       magref_length, is_causal);
>>         j += 4;
>>     }
>>     last_width = width % 4;
>>     if (last_width)
>>         jpeg2000_process_stripes_block(&sp_dec, i, j, last_width, b_height, stride,
>>                                        pLSB, sample_buf, block_states, magref_segment,
>> -                                       magref_length);
>> +                                       magref_length, is_causal);
>> }
>> 
>> /**
>>  * See procedure decodeSigPropMag at Rec. ITU-T T.814, 7.5.
>> */
>> -static int
>> +static void
>> jpeg2000_decode_magref_segment( uint16_t width, uint16_t block_height, const int stride,
>>                                 uint8_t *magref_segment,uint32_t magref_length,
>>                                 uint8_t pLSB, int32_t *sample_buf, uint8_t *block_states)
>> @@ -1123,7 +1144,8 @@ jpeg2000_decode_magref_segment( uint16_t width, uint16_t block_height, const int
>>     uint16_t height             = 4;
>>     uint16_t i_start            = 0;
>>     int32_t *sp;
>> -
>> +    int32_t bit;
>> +    int32_t tmp;
>>     jpeg2000_init_mag_ref(&mag_ref, magref_length);
>> 
>>     for (int n1 = 0; n1 < num_v_stripe; n1++) {
>> @@ -1134,9 +1156,13 @@ jpeg2000_decode_magref_segment( uint16_t width, uint16_t block_height, const int
>>                  *  Rec. ITU-T T.814, Figure 7.
>>                  */
>>                 sp = &sample_buf[j + i * stride];
>> -                if (jpeg2000_get_state(i, j, width, HT_SHIFT_SIGMA, block_states) != 0) {
>> -                    jpeg2000_modify_state(i, j, width, 1 << HT_SHIFT_REF_IND, block_states);
>> -                    *sp |= jpeg2000_import_magref_bit(&mag_ref, magref_segment, magref_length) << pLSB;
>> +                if (jpeg2000_get_state(i, j, stride, HT_SHIFT_SIGMA, block_states) != 0) {
>> +                    jpeg2000_modify_state(i, j, stride, 1 << HT_SHIFT_REF_IND, block_states);
>> +                    bit = jpeg2000_import_magref_bit(&mag_ref, magref_segment, magref_length);
>> +                    tmp = 0xFFFFFFFE | (uint32_t)bit;
>> +                    tmp <<= pLSB;
>> +                    sp[0] &= tmp;
>> +                    sp[0] |= 1 << (pLSB - 1); // Add 0.5 (reconstruction parameter = 1/2)
>>                 }
>>             }
>>         }
>> @@ -1146,21 +1172,24 @@ jpeg2000_decode_magref_segment( uint16_t width, uint16_t block_height, const int
>>     for (int j = 0; j < width; j++) {
>>         for (int i = i_start; i < i_start + height; i++) {
>>             sp = &sample_buf[j + i * stride];
>> -            if (jpeg2000_get_state(i, j, width, HT_SHIFT_SIGMA, block_states) != 0) {
>> -                jpeg2000_modify_state(i, j, width, 1 << HT_SHIFT_REF_IND, block_states);
>> -                *sp |= jpeg2000_import_magref_bit(&mag_ref, magref_segment, magref_length) << pLSB;
>> +            if (jpeg2000_get_state(i, j, stride, HT_SHIFT_SIGMA, block_states) != 0) {
>> +                jpeg2000_modify_state(i, j, stride, 1 << HT_SHIFT_REF_IND, block_states);
>> +                bit = jpeg2000_import_magref_bit(&mag_ref, magref_segment, magref_length);
>> +                tmp = 0xFFFFFFFE | (uint32_t)bit;
>> +                tmp <<= pLSB;
>> +                sp[0] &= tmp;
>> +                sp[0] |= 1 << (pLSB - 1); // Add 0.5 (reconstruction parameter = 1/2)
>>             }
>>         }
>>     }
>> -    return 1;
>> }
>> 
>> 
>> int
>> ff_jpeg2000_decode_htj2k(const Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *codsty, Jpeg2000T1Context *t1, Jpeg2000Cblk *cblk,
>> -                         int width, int height, int magp, uint8_t roi_shift)
>> +                         int width, int height, int M_b, uint8_t roi_shift)
>> {
>> -    uint8_t p0 = 0;             // Number of placeholder passes
>> +    uint8_t p0 = 0;             // 3 * p0 = Number of placeholder passes
>>     uint32_t Lcup;              // Length of HT cleanup segment
>>     uint32_t Lref;              // Length of Refinement segment
>>     uint32_t Scup;              // HT cleanup segment suffix length
>> @@ -1174,7 +1203,7 @@ ff_jpeg2000_decode_htj2k(const Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *c
>> 
>>     int z_blk;                  // Number of ht coding pass
>> 
>> -    uint8_t empty_passes;
>> +    uint8_t num_plhd_passes;    // Number of placeholder passes
>> 
>>     StateVars mag_sgn;          // Magnitude and Sign
>>     StateVars mel;              // Adaptive run-length coding
>> @@ -1190,8 +1219,8 @@ ff_jpeg2000_decode_htj2k(const Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *c
>>     uint8_t *block_states = NULL;
>> 
>>     int32_t n, val;             // Post-processing
>> -
>> -    int32_t M_b = magp;
>> +    const uint32_t mask  = UINT32_MAX >> (M_b + 1); // bit mask for ROI detection
>> +    uint8_t num_rempass;
>> 
>>     const int quad_buf_width = width + 4;
>>     const int quad_buf_height = height + 4;
>> @@ -1201,22 +1230,17 @@ ff_jpeg2000_decode_htj2k(const Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *c
>>     av_assert0(width * height <= 4096);
>>     av_assert0(width * height > 0);
>> 
>> -    if (roi_shift)
>> -        avpriv_report_missing_feature(s->avctx, "ROI shift");
>> -
>>     memset(t1->data, 0, t1->stride * height * sizeof(*t1->data));
>>     memset(t1->flags, 0, t1->stride * (height + 2) * sizeof(*t1->flags));
>> 
>>     if (cblk->npasses == 0)
>>         return 0;
>> 
>> -    if (cblk->npasses > 3)
>> -        p0 = 0;
>> -    else if (cblk->length == 0)
>> -        p0 = 1;
>> -
>> -    empty_passes = p0 * 3;
>> -    z_blk = cblk->npasses - empty_passes;
>> +    num_rempass = cblk->npasses % 3;  // Number of remainder passes
>> +    num_plhd_passes = num_rempass ? cblk->npasses - num_rempass : cblk->npasses - 3;
>> +    av_assert0(num_plhd_passes % 3 == 0);
>> +    p0 = num_plhd_passes / 3;
>> +    z_blk = cblk->npasses - num_plhd_passes;
>> 
>>     if (z_blk <= 0)
>>         return 0; // No passes within this set, continue
>> @@ -1231,7 +1255,11 @@ ff_jpeg2000_decode_htj2k(const Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *c
>>     }
>>     Dcup = cblk->data;
>>     Dref  = cblk->data + Lcup; // Dref comes after the refinement segment
>> +
>> +    cblk->data[cblk->length] = 0xFF; // an extra byte for refinement segment (buffer->last)
>> +
>>     S_blk = p0 + cblk->zbp;
>> +    cblk->zbp = S_blk - 1;
>>     pLSB  = 30 - S_blk;
>> 
>>     Scup = (Dcup[Lcup - 1] << 4) + (Dcup[Lcup - 2] & 0x0F);
>> @@ -1277,31 +1305,32 @@ ff_jpeg2000_decode_htj2k(const Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *c
>>         goto free;
>>     }
>> 
>> -    if (cblk->npasses > 1)
>> +    if (z_blk > 1)
>>         jpeg2000_decode_sigprop_segment(cblk, width, height, quad_buf_width, Dref, Lref,
>>                                         pLSB - 1, sample_buf, block_states);
>> 
>> -    if (cblk->npasses > 2) {
>> -
>> -        if (Lref < 2){
>> -            av_log(s->avctx,AV_LOG_ERROR,"Invalid magnitude refinement length\n");
>> -            ret = AVERROR_INVALIDDATA;
>> -            goto free;
>> -        }
>> -        if ((ret = jpeg2000_decode_magref_segment(width, height, quad_buf_width, Dref, Lref,
>> -                                                  pLSB - 1, sample_buf, block_states)) < 0)
>> -            goto free;
>> -    }
>> +    if (z_blk > 2)
>> +        jpeg2000_decode_magref_segment(width, height, quad_buf_width, Dref, Lref,
>> +                                       pLSB - 1, sample_buf, block_states);
>> 
>>     pLSB = 31 - M_b;
>> 
>>     /* Reconstruct the sample values */
>>     for (int y = 0; y < height; y++) {
>>         for (int x = 0; x < width; x++) {
>> +            int32_t sign;
>> +
>>             n = x + (y * t1->stride);
>>             val = sample_buf[x + (y * quad_buf_width)];
>> +            sign = val & INT32_MIN;
>> +            val &= INT32_MAX;
>> +            /* ROI shift, if necessary */
>> +            if (roi_shift && (((uint32_t)val & ~mask) == 0))
>> +                val <<= roi_shift;
>>             /* Convert sign-magnitude to two's complement. */
>> -            val = val >> 31 ? 0x80000000 - val : val;
>> +            if (sign)
>> +                val = -val;
>> +            /* Shift down to 1 bit upper from decimal point for reconstruction value (= 0.5) */
>>             val >>= (pLSB - 1);
>>             t1->data[n] = val;
>>         }
>> diff --git a/libavcodec/jpeg2000htdec.h b/libavcodec/jpeg2000htdec.h
>> index 572d095c92..8d6919a0de 100644
>> --- a/libavcodec/jpeg2000htdec.h
>> +++ b/libavcodec/jpeg2000htdec.h
>> @@ -29,6 +29,6 @@
>> 
>> int ff_jpeg2000_decode_htj2k(const Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *codsty,
>>                             Jpeg2000T1Context *t1, Jpeg2000Cblk *cblk, int width,
>> -                            int height, int magp, uint8_t roi_shift);
>> +                            int height, int M_b, uint8_t roi_shift);
>> 
>> #endif /* AVCODEC_JPEG2000HTDEC_H */
>> --
>> 2.34.1
>> 



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