[FFmpeg-devel] [PATCH] avformat/fivdec: cached keyframes before video or audio stream was created

[Steven Liu]

2016-07-20 21:46 GMT+08:00 XinZheng Zhang <zhangxzheng at gmail.com>:

> There has an error when seeking in a flv file, which key frames was
> sorted before video frame.
> This ensures that all the key frames was cached, and add to
> corresponding stream when it was created.
>
> On Wed, Jul 20, 2016 at 9:30 PM, zhangxinzheng <zhangxzheng at gmail.com>
> wrote:
> > From: Xinzheng Zhang <zhangxzheng at gmail.com>
> >
> > ---
> >  libavformat/flvdec.c | 52
> +++++++++++++++++++++++++++++++++++++++++++++-------
> >  1 file changed, 45 insertions(+), 7 deletions(-)
> >
> > diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
> > index 2bf1e05..8a73b68 100644
> > --- a/libavformat/flvdec.c
> > +++ b/libavformat/flvdec.c
> > @@ -30,6 +30,7 @@
> >  #include "libavutil/opt.h"
> >  #include "libavutil/intfloat.h"
> >  #include "libavutil/mathematics.h"
> > +#include "libavutil/mem.h"
> >  #include "libavcodec/bytestream.h"
> >  #include "libavcodec/mpeg4audio.h"
> >  #include "avformat.h"
> > @@ -41,6 +42,12 @@
> >
> >  #define RESYNC_BUFFER_SIZE (1<<20)
> >
> > +
> > +typedef struct FLVKeyFrame {
> > +    int64_t pos;
> > +    int64_t timestamp;
> > +} FLVKeyFrame;
> > +
> >  typedef struct FLVContext {
> >      const AVClass *class; ///< Class for private options.
> >      int trust_metadata;   ///< configure streams according onMetaData
> > @@ -61,6 +68,10 @@ typedef struct FLVContext {
> >
> >      int broken_sizes;
> >      int sum_flv_tag_size;
> > +
> > +    int head_flags; //r8
> > +    FLVKeyFrame *keyframes;
> > +    int keyframe_count;
> >  } FLVContext;
> >
> >  static int probe(AVProbeData *p, int live)
> > @@ -95,6 +106,9 @@ static int live_flv_probe(AVProbeData *p)
> >  static AVStream *create_stream(AVFormatContext *s, int codec_type)
> >  {
> >      AVStream *st = avformat_new_stream(s, NULL);
> > +    FLVContext *flv = s->priv_data;
> > +    int flags = flv->head_flags;
> > +    int i = 0;
> >      if (!st)
> >          return NULL;
> >      st->codecpar->codec_type = codec_type;
> > @@ -104,6 +118,17 @@ static AVStream *create_stream(AVFormatContext *s,
> int codec_type)
> >          s->ctx_flags &= ~AVFMTCTX_NOHEADER;
> >
> >      avpriv_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
> > +    if ((!(flags & FLV_HEADER_FLAG_HASVIDEO) && codec_type ==
> AVMEDIA_TYPE_AUDIO) ||
> > +        (codec_type == AVMEDIA_TYPE_VIDEO)
> > +        ) {
> > +        for (; i < flv->keyframe_count; i++) {
> > +            FLVKeyFrame *keyframe = &flv->keyframes[i];
> > +            av_add_index_entry(st, keyframe->pos, keyframe->timestamp,
> > +                               0, 0, AVINDEX_KEYFRAME);
> > +        }
> > +        flv->keyframe_count = 0;
> > +        av_freep(&flv->keyframes);
> > +    }
> >      return st;
> >  }
> >
> > @@ -306,7 +331,7 @@ static int amf_get_string(AVIOContext *ioc, char
> *buffer, int buffsize)
> >  }
> >
> >  static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc,
> > -                                 AVStream *vstream, int64_t max_pos)
> > +                                 AVStream *vstream, AVStream *astream,
> int64_t max_pos)
> >  {
> >      FLVContext *flv       = s->priv_data;
> >      unsigned int timeslen = 0, fileposlen = 0, i;
> > @@ -315,8 +340,12 @@ static int parse_keyframes_index(AVFormatContext
> *s, AVIOContext *ioc,
> >      int64_t *filepositions = NULL;
> >      int ret                = AVERROR(ENOSYS);
> >      int64_t initial_pos    = avio_tell(ioc);
> > +    int head_flags         = flv->head_flags;
> > +    AVStream *kf_stream    = vstream;
> > +    if (!kf_stream && astream && (!(head_flags &
> FLV_HEADER_FLAG_HASVIDEO) && (head_flags & FLV_HEADER_FLAG_HASAUDIO)))
> > +        kf_stream = astream;
> >
> > -    if (vstream->nb_index_entries>0) {
> > +    if (kf_stream && kf_stream->nb_index_entries > 0) {
> >          av_log(s, AV_LOG_WARNING, "Skipping duplicate index\n");
> >          return 0;
> >      }
> > @@ -369,8 +398,16 @@ static int parse_keyframes_index(AVFormatContext
> *s, AVIOContext *ioc,
> >
> >      if (timeslen == fileposlen && fileposlen>1 && max_pos <=
> filepositions[0]) {
> >          for (i = 0; i < fileposlen; i++) {
> > -            av_add_index_entry(vstream, filepositions[i], times[i] *
> 1000,
> > -                               0, 0, AVINDEX_KEYFRAME);
> > +            if (kf_stream) {
> > +                av_add_index_entry(kf_stream, filepositions[i],
> times[i] * 1000,
> > +                                   0, 0, AVINDEX_KEYFRAME);
> > +            } else {
> > +                FLVKeyFrame frame = {0};
> > +                frame.pos = filepositions[i];
> > +                frame.timestamp = times[i] * 1000;
> > +                av_dynarray2_add((void **)&flv->keyframes,
> &flv->keyframe_count,sizeof(FLVKeyFrame), (const uint8_t *)&frame);
> > +            }
> > +
> >              if (i < 2) {
> >                  flv->validate_index[i].pos = filepositions[i];
> >                  flv->validate_index[i].dts = times[i] * 1000;
> > @@ -418,10 +455,10 @@ static int amf_parse_object(AVFormatContext *s,
> AVStream *astream,
> >          }
> >          break;
> >      case AMF_DATA_TYPE_OBJECT:
> > -        if ((vstream || astream) && key &&
> > +        if (key &&
> >              ioc->seekable &&
> >              !strcmp(KEYFRAMES_TAG, key) && depth == 1)
> > -            if (parse_keyframes_index(s, ioc, vstream ? vstream :
> astream,
> > +            if (parse_keyframes_index(s, ioc, vstream, astream,
> >                                        max_pos) < 0)
> >                  av_log(s, AV_LOG_ERROR, "Keyframe index parsing
> failed\n");
> >
> > @@ -633,7 +670,7 @@ static int flv_read_header(AVFormatContext *s)
> >      int offset;
> >
> >      avio_skip(s->pb, 4);
> > -    avio_r8(s->pb); // flags
> > +    flv->head_flags = avio_r8(s->pb); // flags
> >
> >      s->ctx_flags |= AVFMTCTX_NOHEADER;
> >
> > @@ -653,6 +690,7 @@ static int flv_read_close(AVFormatContext *s)
> >      FLVContext *flv = s->priv_data;
> >      for (i=0; i<FLV_STREAM_TYPE_NB; i++)
> >          av_freep(&flv->new_extradata[i]);
> > +    av_freep(&flv->keyframes);
> >      return 0;
> >  }
> >
> > --
> > 2.5.4 (Apple Git-61)
> >
>

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