[FFmpeg-devel] [PATCH] movenc: support non-standard DVD subtitles muxing.

[Philip Langdale]

On Mon,  9 Jul 2012 10:30:51 +0200
Nicolas George <nicolas.george at normalesup.org> wrote:

> The format is imitated on what can be found in the file
> unsupported-embedded-subs-2.mp4 from the MPlayer sample collection.
> The subtitles in a file remuxed from that sample can now be decoded
> by ffplay and vlc (2.0.2).
> 
> Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
> ---
>  libavformat/movenc.c |    9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> index 89072d5..51bf97b 100644
> --- a/libavformat/movenc.c
> +++ b/libavformat/movenc.c
> @@ -325,6 +325,8 @@ static int mov_write_esds_tag(AVIOContext *pb,
> MOVTrack *track) // Basic // plus 1 bit to indicate upstream and 1
> bit set to 1 (reserved) if(track->enc->codec_type ==
> AVMEDIA_TYPE_AUDIO) avio_w8(pb, 0x15); // flags (= Audiostream)
> +    else if(track->enc->codec_type == AVMEDIA_TYPE_SUBTITLE)
> +        avio_w8(pb, 0xE1); // flags
>      else
>          avio_w8(pb, 0x11); // flags (= Visualstream)
>  
> @@ -997,11 +999,17 @@ static int mov_write_subtitle_tag(AVIOContext
> *pb, MOVTrack *track) {
>      int64_t pos = avio_tell(pb);
>      avio_wb32(pb, 0);    /* size */
> +    if (track->enc->codec_id == CODEC_ID_DVD_SUBTITLE)
> +        ffio_wfourcc(pb, "mp4s");
> +    else
>      avio_wl32(pb, track->tag); // store it byteswapped
>      avio_wb32(pb, 0);    /* Reserved */
>      avio_wb16(pb, 0);    /* Reserved */
>      avio_wb16(pb, 1);    /* Data-reference index */
>  
> +    if (track->enc->codec_id == CODEC_ID_DVD_SUBTITLE)
> +        mov_write_esds_tag(pb, track);
> +    else
>      if (track->enc->extradata_size)
>          avio_write(pb, track->enc->extradata,
> track->enc->extradata_size); 
> @@ -1388,6 +1396,7 @@ static int mov_write_hdlr_tag(AVIOContext *pb,
> MOVTrack *track) descr = "SoundHandler";
>          } else if (track->enc->codec_type == AVMEDIA_TYPE_SUBTITLE) {
>              if (track->tag == MKTAG('t','x','3','g')) hdlr_type =
> "sbtl";
> +            else if (track->tag == 0xE0)              hdlr_type =
> "subp"; else                                      hdlr_type = "text";
>              descr = "SubtitleHandler";
>          } else if (track->enc->codec_tag == MKTAG('t','m','c','d')) {

Looks reasonable to me, and matches what I've seen in other dvd subtitle
samples.


--phil