[FFmpeg-devel] [PATCH 2/2] avcodec/mjpegdec: postpone calling ff_get_buffer() until the SOS marker
James Almer
jamrial at gmail.com
Wed Apr 21 21:00:24 EEST 2021
On 4/21/2021 2:52 PM, Andreas Rheinhardt wrote:
> James Almer:
>> With JPEG-LS PAL8 samples, the JPEG-LS extension parameters signaled with
>> the LSE marker show up after SOF but before SOS. For those, the pixel format
>> chosen by get_format() in SOF is GRAY8, and then replaced by PAL8 in LSE.
>> This has not been an issue given both pixel formats allocate the second data
>> plane for the palette, but after the upcoming soname bump, GRAY8 will no longer
>> do that. This will result in segfauls when ff_jpegls_decode_lse() attempts to
>> write the palette on a buffer originally allocated as a GRAY8 one.
>>
>> Work around this by calling ff_get_buffer() after the actual pixel format is
>> known.
>>
>> Signed-off-by: James Almer <jamrial at gmail.com>
>> ---
>> With this, the removal of AV_PIX_FMT_FLAG_PSEUDOPAL will no longer generate
>> segfauls.
>> I can't test hwaccels like vaapi to ensure things still work as inteded, seeing
>> i also had to move the call to start_frame().
>>
>> Better solutions are very much welcome.
>>
>> libavcodec/jpeglsdec.c | 6 ++--
>> libavcodec/mjpegdec.c | 72 +++++++++++++++++++++++-------------------
>> libavcodec/mjpegdec.h | 2 ++
>> 3 files changed, 43 insertions(+), 37 deletions(-)
>>
>> diff --git a/libavcodec/jpeglsdec.c b/libavcodec/jpeglsdec.c
>> index d79bbe1ee3..e3ffec59bf 100644
>> --- a/libavcodec/jpeglsdec.c
>> +++ b/libavcodec/jpeglsdec.c
>> @@ -108,9 +108,8 @@ int ff_jpegls_decode_lse(MJpegDecodeContext *s)
>> if (s->palette_index > maxtab)
>> return AVERROR_INVALIDDATA;
>>
>> - if ((s->avctx->pix_fmt == AV_PIX_FMT_GRAY8 || s->avctx->pix_fmt == AV_PIX_FMT_PAL8) &&
>> - (s->picture_ptr->format == AV_PIX_FMT_GRAY8 || s->picture_ptr->format == AV_PIX_FMT_PAL8)) {
>> - uint32_t *pal = (uint32_t *)s->picture_ptr->data[1];
>> + if (s->avctx->pix_fmt == AV_PIX_FMT_GRAY8 || s->avctx->pix_fmt == AV_PIX_FMT_PAL8) {
>> + uint32_t *pal = (uint32_t *)s->palette;
>
> There is nothing guaranteeing proper alignment for s->palette. Better
> use an uint32_t[AVPALETTE_COUNT] for it.
Changed locally. Thanks.
>
>> int shift = 0;
>>
>> if (s->avctx->bits_per_raw_sample > 0 && s->avctx->bits_per_raw_sample < 8) {
>> @@ -118,7 +117,6 @@ int ff_jpegls_decode_lse(MJpegDecodeContext *s)
>> shift = 8 - s->avctx->bits_per_raw_sample;
>> }
>>
>> - s->picture_ptr->format =
>> s->avctx->pix_fmt = AV_PIX_FMT_PAL8;
>> for (i=s->palette_index; i<=maxtab; i++) {
>> uint8_t k = i << shift;
>> diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
>> index 7c66ff8637..cf65955891 100644
>> --- a/libavcodec/mjpegdec.c
>> +++ b/libavcodec/mjpegdec.c
>> @@ -681,11 +681,13 @@ int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
>> } else if (s->nb_components != 1) {
>> av_log(s->avctx, AV_LOG_ERROR, "Unsupported number of components %d\n", s->nb_components);
>> return AVERROR_PATCHWELCOME;
>> - } else if (s->palette_index && s->bits <= 8)
>> - s->avctx->pix_fmt = AV_PIX_FMT_PAL8;
>> - else if (s->bits <= 8)
>> - s->avctx->pix_fmt = AV_PIX_FMT_GRAY8;
>> - else
>> + } else if (s->bits <= 8) {
>> + avpriv_set_systematic_pal2((uint32_t *)s->palette, s->avctx->pix_fmt);
>> + if (s->palette_index)
>> + s->avctx->pix_fmt = AV_PIX_FMT_PAL8;
>> + else
>> + s->avctx->pix_fmt = AV_PIX_FMT_GRAY8;
>> + } else
>> s->avctx->pix_fmt = AV_PIX_FMT_GRAY16;
>> }
>>
>> @@ -716,27 +718,13 @@ int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
>> s->avctx->pix_fmt = s->hwaccel_pix_fmt;
>> }
>>
>> + s->got_picture = 1;
>> +
>> if (s->avctx->skip_frame == AVDISCARD_ALL) {
>> s->picture_ptr->pict_type = AV_PICTURE_TYPE_I;
>> s->picture_ptr->key_frame = 1;
>> - s->got_picture = 1;
>> return 0;
>> }
>> -
>> - av_frame_unref(s->picture_ptr);
>> - if (ff_get_buffer(s->avctx, s->picture_ptr, AV_GET_BUFFER_FLAG_REF) < 0)
>> - return -1;
>> - s->picture_ptr->pict_type = AV_PICTURE_TYPE_I;
>> - s->picture_ptr->key_frame = 1;
>> - s->got_picture = 1;
>> -
>> - for (i = 0; i < 4; i++)
>> - s->linesize[i] = s->picture_ptr->linesize[i] << s->interlaced;
>> -
>> - ff_dlog(s->avctx, "%d %d %d %d %d %d\n",
>> - s->width, s->height, s->linesize[0], s->linesize[1],
>> - s->interlaced, s->avctx->height);
>> -
>> }
>>
>> if ((s->rgb && !s->lossless && !s->ls) ||
>> @@ -764,18 +752,6 @@ int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
>> memset(s->coefs_finished, 0, sizeof(s->coefs_finished));
>> }
>>
>> - if (s->avctx->hwaccel) {
>> - s->hwaccel_picture_private =
>> - av_mallocz(s->avctx->hwaccel->frame_priv_data_size);
>> - if (!s->hwaccel_picture_private)
>> - return AVERROR(ENOMEM);
>> -
>> - ret = s->avctx->hwaccel->start_frame(s->avctx, s->raw_image_buffer,
>> - s->raw_image_buffer_size);
>> - if (ret < 0)
>> - return ret;
>> - }
>> -
>> return 0;
>> }
>>
>> @@ -1636,6 +1612,36 @@ int ff_mjpeg_decode_sos(MJpegDecodeContext *s, const uint8_t *mb_bitmask,
>> return -1;
>> }
>>
>> + if (!s->interlaced || !(s->bottom_field == !s->interlace_polarity)) {
>> + av_frame_unref(s->picture_ptr);
>> + if (ff_get_buffer(s->avctx, s->picture_ptr, AV_GET_BUFFER_FLAG_REF) < 0)
>> + return -1;
>> + s->picture_ptr->pict_type = AV_PICTURE_TYPE_I;
>> + s->picture_ptr->key_frame = 1;
>> +
>> + for (i = 0; i < 4; i++)
>> + s->linesize[i] = s->picture_ptr->linesize[i] << s->interlaced;
>> +
>> + if (s->picture_ptr->format == AV_PIX_FMT_PAL8)
>> + memcpy(s->picture_ptr->data[1], s->palette, sizeof(s->palette));
>> +
>> + ff_dlog(s->avctx, "%d %d %d %d %d %d\n",
>> + s->width, s->height, s->linesize[0], s->linesize[1],
>> + s->interlaced, s->avctx->height);
>> + }
>> +
>> + if (s->avctx->hwaccel && !s->hwaccel_picture_private) {
>> + s->hwaccel_picture_private =
>> + av_mallocz(s->avctx->hwaccel->frame_priv_data_size);
>> + if (!s->hwaccel_picture_private)
>> + return AVERROR(ENOMEM);
>> +
>> + ret = s->avctx->hwaccel->start_frame(s->avctx, s->raw_image_buffer,
>> + s->raw_image_buffer_size);
>> + if (ret < 0)
>> + return ret;
>> + }
>> +
>> if (reference) {
>> if (reference->width != s->picture_ptr->width ||
>> reference->height != s->picture_ptr->height ||
>> diff --git a/libavcodec/mjpegdec.h b/libavcodec/mjpegdec.h
>> index 2400a179f1..f66bdf0cd9 100644
>> --- a/libavcodec/mjpegdec.h
>> +++ b/libavcodec/mjpegdec.h
>> @@ -165,7 +165,9 @@ typedef struct MJpegDecodeContext {
>> enum AVPixelFormat hwaccel_sw_pix_fmt;
>> enum AVPixelFormat hwaccel_pix_fmt;
>> void *hwaccel_picture_private;
>> +
>> struct JLSState *jls_state;
>> + uint8_t palette[AVPALETTE_SIZE];
>> } MJpegDecodeContext;
>>
>> int ff_mjpeg_build_vlc(VLC *vlc, const uint8_t *bits_table,
>>
>
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