[FFmpeg-devel] [PATCH] lavc: enable time_base encoding option

[Stefano Sabatini]

On date Friday 2014-01-24 18:11:14 +0100, Stefano Sabatini encoded:
> ---
>  libavcodec/options_table.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavcodec/options_table.h b/libavcodec/options_table.h
> index c82c104..89c30fc 100644
> --- a/libavcodec/options_table.h
> +++ b/libavcodec/options_table.h
> @@ -92,7 +92,7 @@ static const AVOption avcodec_options[] = {
>  {"umh", "umh motion estimation", 0, AV_OPT_TYPE_CONST, {.i64 = ME_UMH }, INT_MIN, INT_MAX, V|E, "me_method" },
>  {"iter", "iter motion estimation", 0, AV_OPT_TYPE_CONST, {.i64 = ME_ITER }, INT_MIN, INT_MAX, V|E, "me_method" },
>  {"extradata_size", NULL, OFFSET(extradata_size), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},
> -{"time_base", NULL, OFFSET(time_base), AV_OPT_TYPE_RATIONAL, {.dbl = 0}, INT_MIN, INT_MAX},
> +{"time_base", NULL, OFFSET(time_base), AV_OPT_TYPE_RATIONAL, {.dbl = 0}, INT_MIN, INT_MAX, V|E},

Any reason why this is not enabled?

Anyway I have all kind of weird behaviors if I use it, for example
libx264 sets the FPS based on this value:
   x4->params.i_fps_num = x4->params.i_timebase_den = avctx->time_base.den;
   x4->params.i_fps_den = x4->params.i_timebase_num = avctx->time_base.num;

I need to set this to improve timestamp accuracy when transcoding,
otherwise I get significant rounding errors when passing e.g. from
1/1000000 -> 1001/24000. Comments are welcome.
-- 
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