[FFmpeg-devel] [PATCH 7/7] Handle AVID MJPEG streams directly in the MJPEG decoder.

James Almer jamrial at gmail.com
Sun Dec 13 02:17:52 EET 2020


On 12/12/2020 12:45 PM, Anton Khirnov wrote:
> AVID streams, currently handled by the AVRN decoder can be (depending on
> extradata contents) either MJPEG or raw video. To decode the MJPEG
> variant, the AVRN decoder currently instantiates a MJPEG decoder
> internally and forwards decoded frames to the caller (possibly after
> cropping them).
> 
> This is suboptimal, because the AVRN decoder does not forward all the
> features of the internal MJPEG decoder, such as direct rendering.
> Handling such forwarding in a full and generic manner would be quite
> hard, so it is simpler to just handle those streams in the MJPEG decoder
> directly.
> 
> The AVRN decoder, which now handles only the raw streams, can now be
> marked as supporting direct rendering.
> 
> This also removes the last remaining internal use of the obsolete
> decoding API.
> ---
>   libavcodec/avrndec.c  | 74 ++-----------------------------------------
>   libavcodec/mjpegdec.c | 11 +++++++
>   libavcodec/version.h  |  2 +-
>   libavformat/avidec.c  |  6 ++++
>   libavformat/isom.c    |  2 +-
>   libavformat/version.h |  2 +-
>   tests/fate/video.mak  |  2 +-
>   7 files changed, 23 insertions(+), 76 deletions(-)
> 
> diff --git a/libavcodec/avrndec.c b/libavcodec/avrndec.c
> index d85e3c2000..a80851cefa 100644
> --- a/libavcodec/avrndec.c
> +++ b/libavcodec/avrndec.c
> @@ -21,13 +21,10 @@
>   
>   #include "avcodec.h"
>   #include "internal.h"
> -#include "mjpeg.h"
> -#include "mjpegdec.h"

You can probably also remove the jpegtables dep in configure and the 
mjpegdec.o entry in Makefile for the avrn decoder.

> +
>   #include "libavutil/imgutils.h"
>   
>   typedef struct {
> -    AVCodecContext *mjpeg_avctx;
> -    int is_mjpeg;
>       int interlace;
>       int tff;
>   } AVRnContext;
> @@ -37,42 +34,6 @@ static av_cold int init(AVCodecContext *avctx)
>       AVRnContext *a = avctx->priv_data;
>       int ret;
>   
> -    // Support "Resolution 1:1" for Avid AVI Codec
> -    a->is_mjpeg = avctx->extradata_size < 31 || memcmp(&avctx->extradata[28], "1:1", 3);
> -
> -    if(!a->is_mjpeg && avctx->lowres) {
> -        av_log(avctx, AV_LOG_ERROR, "lowres is not possible with rawvideo\n");
> -        return AVERROR(EINVAL);
> -    }
> -
> -    if(a->is_mjpeg) {
> -        const AVCodec *codec = avcodec_find_decoder(AV_CODEC_ID_MJPEG);
> -        AVDictionary *thread_opt = NULL;
> -        if (!codec) {
> -            av_log(avctx, AV_LOG_ERROR, "MJPEG codec not found\n");
> -            return AVERROR_DECODER_NOT_FOUND;
> -        }
> -
> -        a->mjpeg_avctx = avcodec_alloc_context3(codec);
> -        if (!a->mjpeg_avctx)
> -            return AVERROR(ENOMEM);
> -
> -        av_dict_set(&thread_opt, "threads", "1", 0); // Is this needed ?
> -        a->mjpeg_avctx->refcounted_frames = 1;
> -        a->mjpeg_avctx->flags = avctx->flags;
> -        a->mjpeg_avctx->idct_algo = avctx->idct_algo;
> -        a->mjpeg_avctx->lowres = avctx->lowres;
> -        a->mjpeg_avctx->width = avctx->width;
> -        a->mjpeg_avctx->height = avctx->height;
> -
> -        if ((ret = avcodec_open2(a->mjpeg_avctx, codec, &thread_opt)) < 0) {
> -            av_log(avctx, AV_LOG_ERROR, "MJPEG codec failed to open\n");
> -        }
> -        av_dict_free(&thread_opt);
> -
> -        return ret;
> -    }
> -
>       if ((ret = av_image_check_size(avctx->width, avctx->height, 0, avctx)) < 0)
>           return ret;
>   
> @@ -89,15 +50,6 @@ static av_cold int init(AVCodecContext *avctx)
>       return 0;
>   }
>   
> -static av_cold int end(AVCodecContext *avctx)
> -{
> -    AVRnContext *a = avctx->priv_data;
> -
> -    avcodec_free_context(&a->mjpeg_avctx);
> -
> -    return 0;
> -}
> -
>   static int decode_frame(AVCodecContext *avctx, void *data,
>                           int *got_frame, AVPacket *avpkt)
>   {
> @@ -107,28 +59,6 @@ static int decode_frame(AVCodecContext *avctx, void *data,
>       int buf_size       = avpkt->size;
>       int y, ret, true_height;
>   
> -    if(a->is_mjpeg) {
> -        ret = avcodec_decode_video2(a->mjpeg_avctx, data, got_frame, avpkt);
> -
> -        if (ret >= 0 && *got_frame && avctx->width <= p->width && avctx->height <= p->height) {
> -            int shift = p->height - avctx->height;
> -            int subsample_h, subsample_v;
> -
> -            av_pix_fmt_get_chroma_sub_sample(p->format, &subsample_h, &subsample_v);
> -
> -            p->data[0] += p->linesize[0] * shift;
> -            if (p->data[2]) {
> -                p->data[1] += p->linesize[1] * (shift>>subsample_v);
> -                p->data[2] += p->linesize[2] * (shift>>subsample_v);
> -            }
> -
> -            p->width  = avctx->width;
> -            p->height = avctx->height;
> -        }
> -        avctx->pix_fmt = a->mjpeg_avctx->pix_fmt;
> -        return ret;
> -    }
> -
>       true_height    = buf_size / (2*avctx->width);
>   
>       if(buf_size < 2*avctx->width * avctx->height) {
> @@ -167,8 +97,8 @@ AVCodec ff_avrn_decoder = {
>       .id             = AV_CODEC_ID_AVRN,
>       .priv_data_size = sizeof(AVRnContext),
>       .init           = init,
> -    .close          = end,
>       .decode         = decode_frame,
>       .max_lowres     = 3,
> +    .capabilities   = AV_CODEC_CAP_DR1,
>       .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
>   };
> diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
> index ea3f125cca..39a05db35b 100644
> --- a/libavcodec/mjpegdec.c
> +++ b/libavcodec/mjpegdec.c
> @@ -484,6 +484,11 @@ int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
>           size_change = 0;
>       }
>   
> +    if ((s->avctx->codec_tag == MKTAG('A', 'V', 'R', 'n') ||
> +         s->avctx->codec_tag == MKTAG('A', 'V', 'D', 'J')) &&
> +        s->orig_height < s->avctx->height)
> +        s->avctx->height = s->orig_height;
> +
>       if (s->avctx->codec_id == AV_CODEC_ID_SMVJPEG) {
>           s->avctx->height = s->avctx->coded_height / s->smv_frames_per_jpeg;
>           if (s->avctx->height <= 0)
> @@ -2897,6 +2902,12 @@ the_end:
>               return ret;
>           }
>       }
> +    if ((avctx->codec_tag == MKTAG('A', 'V', 'R', 'n') ||
> +         avctx->codec_tag == MKTAG('A', 'V', 'D', 'J')) &&
> +        avctx->coded_height > s->orig_height) {
> +        frame->height   = avctx->coded_height;
> +        frame->crop_top = frame->height - s->orig_height;
> +    }
>   
>       ret = 0;
>   
> diff --git a/libavcodec/version.h b/libavcodec/version.h
> index 5b92afe60a..abfbd63ac8 100644
> --- a/libavcodec/version.h
> +++ b/libavcodec/version.h
> @@ -29,7 +29,7 @@
>   
>   #define LIBAVCODEC_VERSION_MAJOR  58
>   #define LIBAVCODEC_VERSION_MINOR 115
> -#define LIBAVCODEC_VERSION_MICRO 102
> +#define LIBAVCODEC_VERSION_MICRO 103
>   
>   #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
>                                                  LIBAVCODEC_VERSION_MINOR, \
> diff --git a/libavformat/avidec.c b/libavformat/avidec.c
> index 7e527e15ee..0c5fddd597 100644
> --- a/libavformat/avidec.c
> +++ b/libavformat/avidec.c
> @@ -838,6 +838,12 @@ static int avi_read_header(AVFormatContext *s)
>                           st->codecpar->codec_tag == MKTAG('H', '2', '6', '5'))
>                           st->need_parsing = AVSTREAM_PARSE_FULL;
>   
> +                    if (st->codecpar->codec_id  == AV_CODEC_ID_AVRN &&
> +                        st->codecpar->codec_tag == MKTAG('A', 'V', 'R', 'n') &&
> +                        (st->codecpar->extradata_size < 31 ||
> +                          memcmp(&st->codecpar->extradata[28], "1:1", 3)))
> +                        st->codecpar->codec_id = AV_CODEC_ID_MJPEG;
> +
>                       if (st->codecpar->codec_tag == 0 && st->codecpar->height > 0 &&
>                           st->codecpar->extradata_size < 1U << 30) {
>                           st->codecpar->extradata_size += 9;
> diff --git a/libavformat/isom.c b/libavformat/isom.c
> index d1ef6e3407..db84bb417b 100644
> --- a/libavformat/isom.c
> +++ b/libavformat/isom.c
> @@ -115,7 +115,7 @@ const AVCodecTag ff_codec_movvideo_tags[] = {
>   
>       { AV_CODEC_ID_MJPEG,  MKTAG('j', 'p', 'e', 'g') }, /* PhotoJPEG */
>       { AV_CODEC_ID_MJPEG,  MKTAG('m', 'j', 'p', 'a') }, /* Motion-JPEG (format A) */
> -    { AV_CODEC_ID_AVRN ,  MKTAG('A', 'V', 'D', 'J') }, /* MJPEG with alpha-channel (AVID JFIF meridien compressed) */
> +    { AV_CODEC_ID_MJPEG,  MKTAG('A', 'V', 'D', 'J') }, /* MJPEG with alpha-channel (AVID JFIF meridien compressed) */
>   /*  { AV_CODEC_ID_MJPEG,  MKTAG('A', 'V', 'R', 'n') }, *//* MJPEG with alpha-channel (AVID ABVB/Truevision NuVista) */
>       { AV_CODEC_ID_MJPEG,  MKTAG('d', 'm', 'b', '1') }, /* Motion JPEG OpenDML */
>       { AV_CODEC_ID_MJPEGB, MKTAG('m', 'j', 'p', 'b') }, /* Motion-JPEG (format B) */
> diff --git a/libavformat/version.h b/libavformat/version.h
> index b43193bcb1..a2b5901e74 100644
> --- a/libavformat/version.h
> +++ b/libavformat/version.h
> @@ -33,7 +33,7 @@
>   // Also please add any ticket numbers that you believe might be affected here
>   #define LIBAVFORMAT_VERSION_MAJOR  58
>   #define LIBAVFORMAT_VERSION_MINOR  65
> -#define LIBAVFORMAT_VERSION_MICRO 100
> +#define LIBAVFORMAT_VERSION_MICRO 101
>   
>   #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
>                                                  LIBAVFORMAT_VERSION_MINOR, \
> diff --git a/tests/fate/video.mak b/tests/fate/video.mak
> index a5f3107c38..0984b929cb 100644
> --- a/tests/fate/video.mak
> +++ b/tests/fate/video.mak
> @@ -46,7 +46,7 @@ fate-auravision-v2: CMD = framecrc -i $(TARGET_SAMPLES)/auravision/salma-hayek-i
>   FATE_VIDEO-$(call DEMDEC, AVI, AVRN) += fate-avid-interlaced
>   fate-avid-interlaced: CMD = framecrc -i $(TARGET_SAMPLES)/avid/avid_ntsc_interlaced.avi
>   
> -FATE_VIDEO-$(call DEMDEC, MOV, AVRN) += fate-avid-meridian
> +FATE_VIDEO-$(call DEMDEC, MOV, MJPEG) += fate-avid-meridian
>   fate-avid-meridian: CMD = framecrc -i $(TARGET_SAMPLES)/avid/avidmeridianntsc.mov
>   
>   FATE_VIDEO-$(call DEMDEC, BETHSOFTVID, BETHSOFTVID) += fate-bethsoft-vid
> 



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