[FFmpeg-devel] [PATCH] Pass VBV delay to the calling application via ctx

[Måns Rullgård]

Christophe Massiot <massiot at via.ecp.fr> writes:

> VBV delay is useful for T-STD compliance in some TS muxers. It is
> certainly possible to retrieve it by parsing the output of FFmpeg, but
> getting it from the context makes it simpler and less error-prone.

This is probably a good idea.

> ---
>  doc/APIchanges             |    3 +++
>  libavcodec/avcodec.h       |    9 ++++++++-
>  libavcodec/mpegvideo_enc.c |    1 +
>  3 files changed, 12 insertions(+), 1 deletions(-)
>
> diff --git a/doc/APIchanges b/doc/APIchanges
> index b44182d..05e15bf 100644
> --- a/doc/APIchanges
> +++ b/doc/APIchanges
> @@ -13,6 +13,9 @@ libavutil:   2009-03-08
>
>  API changes, most recent first:
>
> +2011-02-08 - X - lavc 52.110.0 - vbv_delay
> +  Add vbv_delay field to AVCodecContext
> +
>  2011-02-06 - fe174fc - lavf 52.97.0 - avio.h
>    Add flag for non-blocking protocols: URL_FLAG_NONBLOCK
>
> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> index f96ae84..05fa743 100644
> --- a/libavcodec/avcodec.h
> +++ b/libavcodec/avcodec.h
> @@ -32,7 +32,7 @@
>  #include "libavutil/cpu.h"
>
>  #define LIBAVCODEC_VERSION_MAJOR 52
> -#define LIBAVCODEC_VERSION_MINOR 109
> +#define LIBAVCODEC_VERSION_MINOR 110
>  #define LIBAVCODEC_VERSION_MICRO  0
>
>  #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
> @@ -2843,6 +2843,13 @@ typedef struct AVCodecContext {
>      int64_t pts_correction_last_pts;       /// PTS of the last frame
>      int64_t pts_correction_last_dts;       /// DTS of the last frame
>
> +    /**
> +     * VBV delay coded in the last frame (in seconds).
> +     * Used for compliant TS muxing.
> +     * - encoding: Set by libavcodec.
> +     * - decoding: unused.
> +     */
> +    double vbv_delay;

I don't like floating-point.  Could this be expressed in some other
units instead?

>  } AVCodecContext;
>
>  /**
> diff --git a/libavcodec/mpegvideo_enc.c b/libavcodec/mpegvideo_enc.c
> index 6167a9b..5b9c34f 100644
> --- a/libavcodec/mpegvideo_enc.c
> +++ b/libavcodec/mpegvideo_enc.c
> @@ -1381,6 +1381,7 @@ vbv_retry:
>              s->vbv_delay_ptr[1]  = vbv_delay>>5;
>              s->vbv_delay_ptr[2] &= 0x07;
>              s->vbv_delay_ptr[2] |= vbv_delay<<3;
> +            avctx->vbv_delay = vbv_delay/90000.;
>          }
>          s->total_bits += s->frame_bits;
>          avctx->frame_bits  = s->frame_bits;
> -- 
> 1.7.1
>

-- 
M?ns Rullg?rd
mans at mansr.com