[FFmpeg-devel] [PATCH 7/7] lavf/mpegtsenc: add automatic bitstream filtering

[Hendrik Leppkes]

On Fri, Dec 4, 2015 at 12:31 PM, Rodger Combs <rodger.combs at gmail.com> wrote:
> ---
>  libavformat/mpegtsenc.c | 65 ++++++++++++++++++++++++++-----------------------
>  1 file changed, 35 insertions(+), 30 deletions(-)
>
> diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
> index 468bad4..a8fb3a2 100644
> --- a/libavformat/mpegtsenc.c
> +++ b/libavformat/mpegtsenc.c
> @@ -698,7 +698,7 @@ static void section_write_packet(MpegTSSection *s, const uint8_t *packet)
>      avio_write(ctx->pb, packet, TS_PACKET_SIZE);
>  }
>
> -static int mpegts_write_header(AVFormatContext *s)
> +static int mpegts_init(AVFormatContext *s)
>  {
>      MpegTSWrite *ts = s->priv_data;
>      MpegTSWriteStream *ts_st;
> @@ -920,26 +920,6 @@ static int mpegts_write_header(AVFormatContext *s)
>
>  fail:
>      av_freep(&pids);
> -    for (i = 0; i < s->nb_streams; i++) {
> -        st    = s->streams[i];
> -        ts_st = st->priv_data;
> -        if (ts_st) {
> -            av_freep(&ts_st->payload);
> -            if (ts_st->amux) {
> -                avformat_free_context(ts_st->amux);
> -                ts_st->amux = NULL;
> -            }
> -        }
> -        av_freep(&st->priv_data);
> -    }
> -
> -    for (i = 0; i < ts->nb_services; i++) {
> -        service = ts->services[i];
> -        av_freep(&service->provider_name);
> -        av_freep(&service->name);
> -        av_freep(&service);
> -    }
> -    av_freep(&ts->services);
>      return ret;
>  }
>
> @@ -1674,20 +1654,27 @@ static int mpegts_write_packet(AVFormatContext *s, AVPacket *pkt)
>
>  static int mpegts_write_end(AVFormatContext *s)
>  {
> +    if (s->pb)
> +        mpegts_write_flush(s);
> +
> +    return 0;
> +}
> +
> +static void mpegts_deinit(AVFormatContext *s)
> +{
>      MpegTSWrite *ts = s->priv_data;
>      MpegTSService *service;
>      int i;
>
> -    if (s->pb)
> -        mpegts_write_flush(s);
> -
>      for (i = 0; i < s->nb_streams; i++) {
>          AVStream *st = s->streams[i];
>          MpegTSWriteStream *ts_st = st->priv_data;
> -        av_freep(&ts_st->payload);
> -        if (ts_st->amux) {
> -            avformat_free_context(ts_st->amux);
> -            ts_st->amux = NULL;
> +        if (ts_st) {
> +            av_freep(&ts_st->payload);
> +            if (ts_st->amux) {
> +                avformat_free_context(ts_st->amux);
> +                ts_st->amux = NULL;
> +            }
>          }
>      }
>
> @@ -1698,8 +1685,24 @@ static int mpegts_write_end(AVFormatContext *s)
>          av_freep(&service);
>      }
>      av_freep(&ts->services);
> +}
>
> -    return 0;
> +static int mpegts_check_bitstream(struct AVFormatContext *s, const AVPacket *pkt)
> +{
> +    int ret = 1;
> +    AVStream *st = s->streams[pkt->stream_index];
> +
> +    if (st->codec->codec_id == AV_CODEC_ID_H264) {
> +        if (pkt->size >= 5 && AV_RB32(pkt->data) != 0x0000001 &&
> +                              AV_RB24(pkt->data) != 0x000001)
> +            ret = ff_stream_add_bitstream_filter(st, "h264_mp4toannexb", NULL);
> +    } else if (st->codec->codec_id == AV_CODEC_ID_HEVC) {
> +        if (pkt->size >= 5 && AV_RB32(pkt->data) != 0x0000001 &&
> +                              AV_RB24(pkt->data) != 0x000001)
> +            ret = ff_stream_add_bitstream_filter(st, "hevc_mp4toannexb", NULL);
> +    }

I'm not sure these checks are entirely perfect, a 4-byte length code
in mp4 style could realistically start with 0x000001xx. Maybe combine
this with a quick check for extradata? mp4 style extradata always
starts with a 0x01 byte.

> +
> +    return ret;
>  }
>
>  static const AVOption options[] = {
> @@ -1803,9 +1806,11 @@ AVOutputFormat ff_mpegts_muxer = {
>      .priv_data_size = sizeof(MpegTSWrite),
>      .audio_codec    = AV_CODEC_ID_MP2,
>      .video_codec    = AV_CODEC_ID_MPEG2VIDEO,
> -    .write_header   = mpegts_write_header,
> +    .init           = mpegts_init,
>      .write_packet   = mpegts_write_packet,
>      .write_trailer  = mpegts_write_end,
> +    .deinit         = mpegts_deinit,
> +    .check_bitstream = mpegts_check_bitstream,
>      .flags          = AVFMT_ALLOW_FLUSH | AVFMT_VARIABLE_FPS,
>      .priv_class     = &mpegts_muxer_class,
>  };
> --
> 2.6.3
>

- Hendrik