[FFmpeg-devel] [PATCH] ivfenc: write duration at end-of-stream.

[Hendrik Leppkes]

On Sat, Jul 11, 2015 at 1:17 PM, Ronald S. Bultje <rsbultje at gmail.com> wrote:
> At the beginning, the value is not initialized.
> ---
>  libavformat/ivfenc.c | 28 +++++++++++++++++++++++++++-
>  1 file changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/libavformat/ivfenc.c b/libavformat/ivfenc.c
> index 1d76c5c..0c81d41 100644
> --- a/libavformat/ivfenc.c
> +++ b/libavformat/ivfenc.c
> @@ -20,6 +20,11 @@
>  #include "avformat.h"
>  #include "libavutil/intreadwrite.h"
>
> +typedef struct IVFEncContext {
> +    unsigned frame_cnt;
> +    uint64_t last_pts, sum_delta_pts;
> +} IVFEncContext;
> +
>  static int ivf_write_header(AVFormatContext *s)
>  {
>      AVCodecContext *ctx;
> @@ -43,7 +48,7 @@ static int ivf_write_header(AVFormatContext *s)
>      avio_wl16(pb, ctx->height);
>      avio_wl32(pb, s->streams[0]->time_base.den);
>      avio_wl32(pb, s->streams[0]->time_base.num);
> -    avio_wl64(pb, s->streams[0]->duration); // TODO: duration or number of frames?!?
> +    avio_wl64(pb, 0xFFFFFFFFFFFFFFFFULL);
>
>      return 0;
>  }
> @@ -51,14 +56,34 @@ static int ivf_write_header(AVFormatContext *s)
>  static int ivf_write_packet(AVFormatContext *s, AVPacket *pkt)
>  {
>      AVIOContext *pb = s->pb;
> +    IVFEncContext *ctx = s->priv_data;
> +
>      avio_wl32(pb, pkt->size);
>      avio_wl64(pb, pkt->pts);
>      avio_write(pb, pkt->data, pkt->size);
> +    if (ctx->frame_cnt)
> +        ctx->sum_delta_pts += pkt->pts - ctx->last_pts;
> +    ctx->frame_cnt++;
> +    ctx->last_pts = pkt->pts;
> +
> +    return 0;
> +}
> +
> +static int ivf_write_trailer(AVFormatContext *s)
> +{
> +    AVIOContext *pb = s->pb;
> +    IVFEncContext *ctx = s->priv_data;
> +    size_t end = avio_tell(pb);
> +
> +    avio_seek(pb, 24, SEEK_SET);
> +    avio_wl64(pb, ctx->frame_cnt * ctx->sum_delta_pts / (ctx->frame_cnt - 1));
> +    avio_seek(pb, end, SEEK_SET);
>
Should probably wrap this in if (pb->seekable) just to be sure.

>      return 0;
>  }
>
>  AVOutputFormat ff_ivf_muxer = {
> +    .priv_data_size = sizeof(IVFEncContext),
>      .name         = "ivf",
>      .long_name    = NULL_IF_CONFIG_SMALL("On2 IVF"),
>      .extensions   = "ivf",
> @@ -66,4 +91,5 @@ AVOutputFormat ff_ivf_muxer = {
>      .video_codec  = AV_CODEC_ID_VP8,
>      .write_header = ivf_write_header,
>      .write_packet = ivf_write_packet,
> +    .write_trailer = ivf_write_trailer,
>  };

Otherwise LGTM.