[FFmpeg-devel] [PATCH] Export H264 profile/level in AVCodecContext

[Michael Niedermayer]

On Thu, Jan 28, 2010 at 02:02:29PM +0100, Rafa?l Carr? wrote:
> Hi,
> 
> profile_idc / level_idc are copied verbatim to avctx after the sps has
> been decoded.
> 
> Add descriptions of the profile to avcodec.h, level is self descriptive.
> 
> 
> I am not sure of what happens in a multi threaded context:
> 
> Is it possible to have a stream with different sequences and different
> profile/level combinations in each SPS ?
> 
> If it's the case I think AVCodecContext shouldn't be modified until all
> the frames from the previous sequence have been decoded (the parser
> should be safe on this point), and I don't know how to do that.
> 
> Thread synchronisation isn't obvious when reading h264.c, I only see
> that execute_decode_slices() is the only user of avctx->execute() and
> that it's called before & after SPS decoding in decode_nal_units()
> 
> If the first context waits for all the other contexts to finish
> execution then it won't be a problem when using multiple threads.
> 
> -- 
> Rafa?l Carr?

>  avcodec.h     |   10 ++++++++++
>  h264.c        |    5 ++++-
>  h264_parser.c |    5 ++++-
>  3 files changed, 18 insertions(+), 2 deletions(-)
> 2c6dd04c26f97edb41acbfce03456497182058f1  h264-profile-level.diff
> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> index aa59097..332ab92 100644
> --- a/libavcodec/avcodec.h
> +++ b/libavcodec/avcodec.h
> @@ -2123,11 +2123,21 @@ typedef struct AVCodecContext {
>       */
>       int profile;
>  #define FF_PROFILE_UNKNOWN -99
> +
>  #define FF_PROFILE_AAC_MAIN 0
>  #define FF_PROFILE_AAC_LOW  1
>  #define FF_PROFILE_AAC_SSR  2
>  #define FF_PROFILE_AAC_LTP  3
>  
> +#define FF_PROFILE_H264_BASELINE    66
> +#define FF_PROFILE_H264_MAIN        77
> +#define FF_PROFILE_H264_EXTENDED    88
> +#define FF_PROFILE_H264_HIGH        100
> +#define FF_PROFILE_H264_HIGH_10     110
> +#define FF_PROFILE_H264_HIGH_422    122
> +#define FF_PROFILE_H264_HIGH_444    244
> +#define FF_PROFILE_H264_CAVLC_444   44
> +
>      /**
>       * level
>       * - encoding: Set by user.
> diff --git a/libavcodec/h264.c b/libavcodec/h264.c
> index e4a47cf..1ebe931 100644
> --- a/libavcodec/h264.c
> +++ b/libavcodec/h264.c
> @@ -2589,7 +2589,10 @@ static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size){
>              break;
>          case NAL_SPS:
>              init_get_bits(&s->gb, ptr, bit_length);
> -            ff_h264_decode_seq_parameter_set(h);
> +            if(!ff_h264_decode_seq_parameter_set(h)) {
> +                avctx->profile = h->sps.profile_idc;
> +                avctx->level   = h->sps.level_idc;
> +            }

The  active profile should be exportet not the one of the last sps


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The greatest way to live with honor in this world is to be what we pretend
to be. -- Socrates
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