[FFmpeg-devel] [PATCH 1/2] avformat/flvdec: add flv_ignore_prevtag option into flvdec

[Steven Liu]

> On May 31, 2018, at 12:40, Steven Liu <lq at chinaffmpeg.org> wrote:
> 
> dump the problem flv to problem_flv.flv.
> liuqideMacBook-Pro:xxx liuqi$ dd if=~/Movies/Test/1.flv of=problem_flv.flv count=81920 bs=1
> 81920+0 records in
> 81920+0 records out
> 81920 bytes transferred in 0.767041 secs (106800 bytes/sec)
> 
> before this patch:
> liuqideMacBook-Pro:xxx liuqi$ ./ffplay problem_flv.flv
> ffplay version N-91141-gc24d247e2c Copyright (c) 2003-2018 the FFmpeg developers
>  built with Apple LLVM version 9.1.0 (clang-902.0.39.1)
>  configuration: --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libspeex --enable-libx264 --enable-libx265 --enable-libfdk-aac --enable-version3 --cc='ccache gcc' --enable-nonfree --enable-videotoolbox --enable-opengl --enable-libxml2 --enable-libsrt
>  libavutil      56. 18.102 / 56. 18.102
>  libavcodec     58. 19.102 / 58. 19.102
>  libavformat    58. 16.100 / 58. 16.100
>  libavdevice    58.  4.100 / 58.  4.100
>  libavfilter     7. 24.100 /  7. 24.100
>  libswscale      5.  2.100 /  5.  2.100
>  libswresample   3.  2.100 /  3.  2.100
>  libpostproc    55.  2.100 / 55.  2.100
> [flv @ 0x7fcfe5821e00] Packet mismatch 355 352 352
> problem_flv.flv: could not find codec parameters
> 
> after this patch:
> liuqideMacBook-Pro:xxx liuqi$ ./ffplay -flv_ignore_prevtag 1 problem_flv.flv
> ffplay version N-91141-gc24d247e2c Copyright (c) 2003-2018 the FFmpeg developers
>  built with Apple LLVM version 9.1.0 (clang-902.0.39.1)
>  configuration: --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libspeex --enable-libx264 --enable-libx265 --enable-libfdk-aac --enable-version3 --cc='ccache gcc' --enable-nonfree --enable-videotoolbox --enable-opengl --enable-libxml2 --enable-libsrt
>  libavutil      56. 18.102 / 56. 18.102
>  libavcodec     58. 19.102 / 58. 19.102
>  libavformat    58. 16.100 / 58. 16.100
>  libavdevice    58.  4.100 / 58.  4.100
>  libavfilter     7. 24.100 /  7. 24.100
>  libswscale      5.  2.100 /  5.  2.100
>  libswresample   3.  2.100 /  3.  2.100
>  libpostproc    55.  2.100 / 55.  2.100
> Input #0, flv, from 'problem_flv.flv':
>  Metadata:
>    fileSize        : 102128061
>    audiochannels   : 2
>    encoder         : obs-output module (libobs version 0.10.1)
>  Duration: 00:05:09.60, start: 0.000000, bitrate: 2 kb/s
>    Stream #0:0: Audio: aac (LC), 44100 Hz, stereo, fltp, 131 kb/s
>    Stream #0:1: Video: h264 (High), yuv420p(tv, bt709, progressive), 960x600, 2560 kb/s, 30 fps, 30 tbr, 1k tbn, 60 tbc
> [h264 @ 0x7fdf64122a00] Invalid NAL unit size (10375 > 1656).=0/0
> [h264 @ 0x7fdf64122a00] Error splitting the input into NAL units.
>   2.14 A-V: -0.013 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0
> 
> Signed-off-by: Steven Liu <lq at chinaffmpeg.org>
> ---
> doc/demuxers.texi    | 3 +++
> libavformat/flvdec.c | 4 ++++
> 2 files changed, 7 insertions(+)
> 
> diff --git a/doc/demuxers.texi b/doc/demuxers.texi
> index 072918be28..5007e6339f 100644
> --- a/doc/demuxers.texi
> +++ b/doc/demuxers.texi
> @@ -269,6 +269,9 @@ ffmpeg -f live_flv -i rtmp://<any.server>/anything/key ....
> @table @option
> @item -flv_metadata @var{bool}
> Allocate the streams according to the onMetaData array content.
> +
> + at item -flv_ignore_prevtag @var{bool}
> +Ignore the size of previous tag value.
> @end table
> 
> @section gif
> diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
> index 34c3e08bad..861cf7c020 100644
> --- a/libavformat/flvdec.c
> +++ b/libavformat/flvdec.c
> @@ -44,6 +44,7 @@
> typedef struct FLVContext {
>     const AVClass *class; ///< Class for private options.
>     int trust_metadata;   ///< configure streams according onMetaData
> +    int trust_datasize;   ///< trust data size of FLVTag
>     int wrong_dts;        ///< wrong dts due to negative cts
>     uint8_t *new_extradata[FLV_STREAM_TYPE_NB];
>     int new_extradata_size[FLV_STREAM_TYPE_NB];
> @@ -1252,6 +1253,7 @@ retry_duration:
> 
> leave:
>     last = avio_rb32(s->pb);
> +    if (!flv->trust_datasize) {
>     if (last != orig_size + 11 && last != orig_size + 10 &&
>         !avio_feof(s->pb) &&
>         (last != orig_size || !last) && last != flv->sum_flv_tag_size &&
> @@ -1264,6 +1266,7 @@ leave:
>             goto retry;
>         }
>     }
> +    }
>     return ret;
> }
> 
> @@ -1279,6 +1282,7 @@ static int flv_read_seek(AVFormatContext *s, int stream_index,
> #define VD AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
> static const AVOption options[] = {
>     { "flv_metadata", "Allocate streams according to the onMetaData array", OFFSET(trust_metadata), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VD },
> +    { "flv_ignore_prevtag", "Ignore the Size of previous tag", OFFSET(trust_datasize), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VD },
>     { "missing_streams", "", OFFSET(missing_streams), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 0xFF, VD | AV_OPT_FLAG_EXPORT | AV_OPT_FLAG_READONLY },
>     { NULL }
> };
> -- 
> 2.15.1
> 

Thanks
Steven

sample file:
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