[FFmpeg-devel] [PATCH 3/3 v2] h264: Run VLC init under pthread_once

[wm4]

On Wed,  7 Oct 2015 12:24:32 -0400
Derek Buitenhuis <derek.buitenhuis at gmail.com> wrote:

> This makes the h.264 decoder threadsafe to initialize.
> 
> Signed-off-by: Derek Buitenhuis <derek.buitenhuis at gmail.com>
> ---
>  libavcodec/h264.c | 9 ++++++++-
>  libavcodec/h264.h | 7 +++++++
>  2 files changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/libavcodec/h264.c b/libavcodec/h264.c
> index 3209c9c..1abdc4b 100644
> --- a/libavcodec/h264.c
> +++ b/libavcodec/h264.c
> @@ -644,6 +644,8 @@ static int h264_init_context(AVCodecContext *avctx, H264Context *h)
>      return 0;
>  }
>  
> +static pthread_once_t ff_h264_vlc_init = PTHREAD_ONCE_INIT;
> +
>  av_cold int ff_h264_decode_init(AVCodecContext *avctx)
>  {
>      H264Context *h = avctx->priv_data;
> @@ -657,7 +659,11 @@ av_cold int ff_h264_decode_init(AVCodecContext *avctx)
>      if (!avctx->has_b_frames)
>          h->low_delay = 1;
>  
> -    ff_h264_decode_init_vlc();
> +    ret = pthread_once(&ff_h264_vlc_init, &ff_h264_decode_init_vlc);
> +    if (ret != 0) {
> +        av_log(avctx, AV_LOG_ERROR, "pthread_once has failed.");
> +        return AVERROR_UNKNOWN;
> +    }
>  
>      if (avctx->codec_id == AV_CODEC_ID_H264) {
>          if (avctx->ticks_per_frame == 1) {
> @@ -1993,6 +1999,7 @@ AVCodec ff_h264_decoder = {
>      .capabilities          = /*AV_CODEC_CAP_DRAW_HORIZ_BAND |*/ AV_CODEC_CAP_DR1 |
>                               AV_CODEC_CAP_DELAY | AV_CODEC_CAP_SLICE_THREADS |
>                               AV_CODEC_CAP_FRAME_THREADS,
> +    .caps_internal         = FF_CODEC_CAP_INIT_THREADSAFE,
>      .flush                 = flush_dpb,
>      .init_thread_copy      = ONLY_IF_THREADS_ENABLED(decode_init_thread_copy),
>      .update_thread_context = ONLY_IF_THREADS_ENABLED(ff_h264_update_thread_context),
> diff --git a/libavcodec/h264.h b/libavcodec/h264.h
> index 769abda..f8a58a6 100644
> --- a/libavcodec/h264.h
> +++ b/libavcodec/h264.h
> @@ -29,6 +29,7 @@
>  #define AVCODEC_H264_H
>  
>  #include "libavutil/intreadwrite.h"
> +#include "libavutil/thread.h"
>  #include "cabac.h"
>  #include "error_resilience.h"
>  #include "get_bits.h"
> @@ -43,6 +44,12 @@
>  #include "rectangle.h"
>  #include "videodsp.h"
>  
> +#if HAVE_PTHREADS
> +#   include <pthread.h>
> +#elif HAVE_W32THREADS
> +#   include "compat/w32pthreads.h"
> +#endif
> +
>  #define H264_MAX_PICTURE_COUNT 36
>  #define H264_MAX_THREADS       32
>  

I think you forgot to remove the second chunk? It's unnecessary with
thread.h included.

Other than that LGTM.