[FFmpeg-devel] [PATCH] avcodec/h264_ps: use the AVBufferPool API to allocate parameter set buffers

Michael Niedermayer michael at niedermayer.cc
Sun Jan 21 04:33:08 EET 2018


On Sat, Jan 20, 2018 at 06:49:29PM -0300, James Almer wrote:
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> Similar rationale as hevc. With up to 32 sps and 256 pps, this may
> come in handy when parsing raw streams.
> 
>  libavcodec/h264_parser.c   |  3 ++-
>  libavcodec/h264_ps.c       | 22 ++++++++++++++++++++--
>  libavcodec/h264_ps.h       |  5 +++++
>  libavcodec/h264dec.c       |  3 +++
>  libavcodec/mediacodecdec.c |  4 ++++
>  5 files changed, 34 insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/h264_parser.c b/libavcodec/h264_parser.c
> index 65d9d44b50..fa6777fc05 100644
> --- a/libavcodec/h264_parser.c
> +++ b/libavcodec/h264_parser.c
> @@ -697,7 +697,8 @@ static av_cold int init(AVCodecParserContext *s)
>      p->reference_dts = AV_NOPTS_VALUE;
>      p->last_frame_num = INT_MAX;
>      ff_h264dsp_init(&p->h264dsp, 8, 1);
> -    return 0;
> +
> +    return ff_h264_ps_init(&p->ps);
>  }
>  
>  AVCodecParser ff_h264_parser = {
> diff --git a/libavcodec/h264_ps.c b/libavcodec/h264_ps.c
> index 8d1ef831fa..50dbabdb8b 100644
> --- a/libavcodec/h264_ps.c
> +++ b/libavcodec/h264_ps.c
> @@ -314,6 +314,21 @@ static int decode_scaling_matrices(GetBitContext *gb, const SPS *sps,
>      return ret;
>  }
>  
> +int ff_h264_ps_init(H264ParamSets *ps)
> +{
> +    ps->sps_pool = av_buffer_pool_init(sizeof(*ps->sps), av_buffer_allocz);
> +    ps->pps_pool = av_buffer_pool_init(sizeof(*ps->pps), av_buffer_allocz);
> +
> +    if (!ps->sps_pool || !ps->pps_pool) {
> +        av_buffer_pool_uninit(&ps->sps_pool);
> +        av_buffer_pool_uninit(&ps->pps_pool);
> +
> +        return AVERROR(ENOMEM);
> +    }
> +
> +    return 0;
> +}
> +
>  void ff_h264_ps_uninit(H264ParamSets *ps)
>  {
>      int i;
> @@ -327,6 +342,9 @@ void ff_h264_ps_uninit(H264ParamSets *ps)
>      av_buffer_unref(&ps->sps_ref);
>      av_buffer_unref(&ps->pps_ref);
>  
> +    av_buffer_pool_uninit(&ps->sps_pool);
> +    av_buffer_pool_uninit(&ps->pps_pool);
> +
>      ps->pps = NULL;
>      ps->sps = NULL;
>  }
> @@ -341,7 +359,7 @@ int ff_h264_decode_seq_parameter_set(GetBitContext *gb, AVCodecContext *avctx,
>      SPS *sps;
>      int ret;
>  
> -    sps_buf = av_buffer_allocz(sizeof(*sps));
> +    sps_buf = av_buffer_pool_get(ps->sps_pool);
>      if (!sps_buf)
>          return AVERROR(ENOMEM);
>      sps = (SPS*)sps_buf->data;
> @@ -738,7 +756,7 @@ int ff_h264_decode_picture_parameter_set(GetBitContext *gb, AVCodecContext *avct
>          return AVERROR_INVALIDDATA;
>      }
>  
> -    pps_buf = av_buffer_allocz(sizeof(*pps));
> +    pps_buf = av_buffer_pool_get(ps->pps_pool);

this seems to remove the memset(0) unless iam missing something
is this intended?
has someone checked this to be safe ?


[...]
> --- a/libavcodec/h264dec.c
> +++ b/libavcodec/h264dec.c
> @@ -326,6 +326,9 @@ static int h264_init_context(AVCodecContext *avctx, H264Context *h)
>  
>      ff_h264_sei_uninit(&h->sei);
>  
> +    if (ff_h264_ps_init(&h->ps) < 0)
> +        return AVERROR(ENOMEM);

This probably should forward the returned error code

also a memcmp on the data might be worth looking into to avoid re-parsing of
unchanged PS
(theres already a memcmp in libavcodec/h264_ps.c)

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Take away the freedom of one citizen and you will be jailed, take away
the freedom of all citizens and you will be congratulated by your peers
in Parliament.
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