[FFmpeg-devel] [PATCH 2/3] lavf/utils: add flag to discard timestamps on corrupted frames

[Michael Niedermayer]

On Thu, Dec 07, 2017 at 10:23:15PM -0600, Rodger Combs wrote:
> ---
>  libavformat/avformat.h      | 1 +
>  libavformat/options_table.h | 1 +
>  libavformat/utils.c         | 8 ++++++++
>  3 files changed, 10 insertions(+)
> 
> diff --git a/libavformat/avformat.h b/libavformat/avformat.h
> index 4f2798a871..d10d583dff 100644
> --- a/libavformat/avformat.h
> +++ b/libavformat/avformat.h
> @@ -1450,6 +1450,7 @@ typedef struct AVFormatContext {
>  #define AVFMT_FLAG_FAST_SEEK   0x80000 ///< Enable fast, but inaccurate seeks for some formats
>  #define AVFMT_FLAG_SHORTEST   0x100000 ///< Stop muxing when the shortest stream stops.
>  #define AVFMT_FLAG_AUTO_BSF   0x200000 ///< Add bitstream filters as requested by the muxer
> +#define AVFMT_FLAG_DISCARD_CORRUPT_TS 0x400000 ///< Discard timestamps of frames marked corrupt
>  
>      /**
>       * Maximum size of the data read from input for determining
> diff --git a/libavformat/options_table.h b/libavformat/options_table.h
> index b8fa47c6fd..515574d3e0 100644
> --- a/libavformat/options_table.h
> +++ b/libavformat/options_table.h
> @@ -58,6 +58,7 @@ static const AVOption avformat_options[] = {
>  {"bitexact", "do not write random/volatile data", 0, AV_OPT_TYPE_CONST, { .i64 = AVFMT_FLAG_BITEXACT }, 0, 0, E, "fflags" },
>  {"shortest", "stop muxing with the shortest stream", 0, AV_OPT_TYPE_CONST, { .i64 = AVFMT_FLAG_SHORTEST }, 0, 0, E, "fflags" },
>  {"autobsf", "add needed bsfs automatically", 0, AV_OPT_TYPE_CONST, { .i64 = AVFMT_FLAG_AUTO_BSF }, 0, 0, E, "fflags" },
> +{"discardcorruptts", "discard timestamps on corrupted frames", 0, AV_OPT_TYPE_CONST, { .i64 = AVFMT_FLAG_DISCARD_CORRUPT_TS }, 0, 0, E, "fflags" },
>  {"analyzeduration", "specify how many microseconds are analyzed to probe the input", OFFSET(max_analyze_duration), AV_OPT_TYPE_INT64, {.i64 = 0 }, 0, INT64_MAX, D},
>  {"cryptokey", "decryption key", OFFSET(key), AV_OPT_TYPE_BINARY, {.dbl = 0}, 0, 0, D},
>  {"indexmem", "max memory used for timestamp index (per stream)", OFFSET(max_index_size), AV_OPT_TYPE_INT, {.i64 = 1<<20 }, 0, INT_MAX, D},
> diff --git a/libavformat/utils.c b/libavformat/utils.c
> index 84e49208b8..98af941e9f 100644
> --- a/libavformat/utils.c
> +++ b/libavformat/utils.c

> @@ -873,6 +873,14 @@ int ff_read_packet(AVFormatContext *s, AVPacket *pkt)
>                  st->cur_dts = wrap_timestamp(st, st->cur_dts);
>          }
>  
> +        if ((s->flags & AVFMT_FLAG_DISCARD_CORRUPT_TS) &&
> +            (pkt->flags & AV_PKT_FLAG_CORRUPT)) {
> +            pkt->pts = pkt->dts = AV_NOPTS_VALUE;
> +            av_log(s, AV_LOG_WARNING,
> +                   "Discarded timestamp on corrupted packet (stream = %d)\n",
> +                   pkt->stream_index);
> +        }

how many of the cases that set AV_PKT_FLAG_CORRUPT can even be due to
the timestamp ?

We set this for truncated / EOF cases and all kinds of stuff that
are known to be unrelated to the timestamps


[...]

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