[FFmpeg-devel] [PATCH]lavf/movenc: Allow to disable writing the timecode track

[Clément Bœsch]

On Sat, Sep 24, 2016 at 10:40:35PM +0200, Carl Eugen Hoyos wrote:
> Hi!
> 
> Not everybody is happy about a timecode track in mp4, 
> see ticket #5492.
> 
> Please comment, Carl Eugen

> From 47a813709643106b0d0a2eceff822107c395d15c Mon Sep 17 00:00:00 2001
> From: Carl Eugen Hoyos <cehoyos at ag.or.at>
> Date: Sat, 24 Sep 2016 22:38:14 +0200
> Subject: [PATCH] lavf/movenc: Allow to disable writing the timecode track.
> 
> Fixes ticket #5492.
> ---
>  doc/muxers.texi      |    3 +++
>  libavformat/movenc.c |    6 ++++--
>  libavformat/movenc.h |    1 +
>  3 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index 27eb9a0..61476ca 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -884,6 +884,9 @@ the new default-base-is-moof flag instead. This flag is new from
>  14496-12:2012. This may make the fragments easier to parse in certain
>  circumstances (avoiding basing track fragment location calculations
>  on the implicit end of the previous track fragment).
> + at item -write_tmcd
> +Specify 1 to force writing a timecode track, 0 to disable it and -1 to
> +write a timecode track only for mov and mp4 output (default).
>  @end table
>  
>  @subsection Example
> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> index 0382309..a5e4ad1 100644
> --- a/libavformat/movenc.c
> +++ b/libavformat/movenc.c
> @@ -90,6 +90,7 @@ static const AVOption options[] = {
>      { "encryption_key", "The media encryption key (hex)", offsetof(MOVMuxContext, encryption_key), AV_OPT_TYPE_BINARY, .flags = AV_OPT_FLAG_ENCODING_PARAM },
>      { "encryption_kid", "The media encryption key identifier (hex)", offsetof(MOVMuxContext, encryption_kid), AV_OPT_TYPE_BINARY, .flags = AV_OPT_FLAG_ENCODING_PARAM },
>      { "use_stream_ids_as_track_ids", "use stream ids as track ids", offsetof(MOVMuxContext, use_stream_ids_as_track_ids), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
> +    { "write_tmcd", "force or disable writing tmcd", offsetof(MOVMuxContext, write_tmcd), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, AV_OPT_FLAG_ENCODING_PARAM},

AV_OPT_TYPE_BOOL

>      { NULL },
>  };
>  
> @@ -2312,7 +2313,7 @@ static int mov_write_minf_tag(AVFormatContext *s, AVIOContext *pb, MOVMuxContext
>      } else if (track->tag == MKTAG('r','t','p',' ')) {
>          mov_write_hmhd_tag(pb);
>      } else if (track->tag == MKTAG('t','m','c','d')) {
> -        if (track->mode == MODE_MP4)
> +        if (track->mode != MODE_MOV)
>              mov_write_nmhd_tag(pb);
>          else
>              mov_write_gmhd_tag(pb, track);
> @@ -5539,7 +5540,8 @@ static int mov_write_header(AVFormatContext *s)
>          }
>      }
>  
> -    if (mov->mode == MODE_MOV || mov->mode == MODE_MP4) {
> +    if (   mov->write_tmcd == -1 && (mov->mode == MODE_MOV || mov->mode == MODE_MP4)
> +        || mov->write_tmcd == 1) {
>          tmcd_track = mov->nb_streams;
>  
>          /* +1 tmcd track for each video stream with a timecode */
> diff --git a/libavformat/movenc.h b/libavformat/movenc.h
> index ea76e39..1f7a9d7 100644
> --- a/libavformat/movenc.h
> +++ b/libavformat/movenc.h
> @@ -219,6 +219,7 @@ typedef struct MOVMuxContext {
>  
>      int use_stream_ids_as_track_ids;
>      int track_ids_ok;
> +    int write_tmcd;
>  } MOVMuxContext;
>  

Didn't test nor looked in depth, but OK if it disable timecode in MP4 by
default. Timecode is only (badly) "standardized" in MOV, so we shouldn't
write such track in MP4.

-- 
Clément B.