[FFmpeg-devel] [PATCH 1/7] avformat/matroskaenc: Write SeekHead when livestreaming

[Andreas Rheinhardt]

Andreas Rheinhardt:
> Commit 6fd300ac6c2c3871736ce0e6df95603255004dc6 added support for WebM
> Chunk livestreaming; in this case, both the header as well as each
> Cluster is written to a file of its own, so that even if the AVIOContext
> seems seekable, the muxer has to behave as if it were not. Yet one of
> the added checks makes no sense: It ensures that no SeekHead is written
> preliminarily (and hence no SeekHead is written at all) if the option
> for livestreaming is set, although one should write the SeekHead in this
> case when writing the Header. E.g. the WebM-DASH specification [1]
> never forbids writing a SeekHead and in some instances (that don't apply
> here) even requires it (if Cues are written after the Clusters).
> 
> [1]: https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification
> 
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> ---
>  libavformat/matroskaenc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
> index 784973a951..dd77ae64bc 100644
> --- a/libavformat/matroskaenc.c
> +++ b/libavformat/matroskaenc.c
> @@ -1896,7 +1896,7 @@ static int mkv_write_header(AVFormatContext *s)
>      if (ret < 0)
>          return ret;
>  
> -    if (!(s->pb->seekable & AVIO_SEEKABLE_NORMAL) && !mkv->is_live) {
> +    if (!(s->pb->seekable & AVIO_SEEKABLE_NORMAL) || mkv->is_live) {
>          ret = mkv_write_seekhead(pb, mkv, 0, avio_tell(pb));
>          if (ret < 0)
>              return ret;
> 
I intend to apply this patchset tomorrow unless there are objections.

- Andreas