[FFmpeg-devel] [PATCH 1/6] cbs: Fragment/unit data is always reference counted

James Almer jamrial at gmail.com
Tue May 1 18:51:24 EEST 2018


On 4/30/2018 8:26 PM, Mark Thompson wrote:
> Make this clear in the documentation and add some asserts to ensure
> that it is always true.
> ---
> As suggested earlier :)
> 
> 
>  libavcodec/cbs.c | 18 ++++++++++++------
>  libavcodec/cbs.h | 10 ++++++----
>  2 files changed, 18 insertions(+), 10 deletions(-)
> 
> diff --git a/libavcodec/cbs.c b/libavcodec/cbs.c
> index d81b4e03f7..0d6ffe8824 100644
> --- a/libavcodec/cbs.c
> +++ b/libavcodec/cbs.c
> @@ -140,26 +140,30 @@ static int cbs_read_fragment_content(CodedBitstreamContext *ctx,
>      int err, i, j;
>  
>      for (i = 0; i < frag->nb_units; i++) {
> +        CodedBitstreamUnit *unit = &frag->units[i];
> +
>          if (ctx->decompose_unit_types) {
>              for (j = 0; j < ctx->nb_decompose_unit_types; j++) {
> -                if (ctx->decompose_unit_types[j] == frag->units[i].type)
> +                if (ctx->decompose_unit_types[j] == unit->type)
>                      break;
>              }
>              if (j >= ctx->nb_decompose_unit_types)
>                  continue;
>          }
>  
> -        av_buffer_unref(&frag->units[i].content_ref);
> -        frag->units[i].content = NULL;
> +        av_buffer_unref(&unit->content_ref);
> +        unit->content = NULL;
> +
> +        av_assert0(unit->data && unit->data_ref);
>  
> -        err = ctx->codec->read_unit(ctx, &frag->units[i]);
> +        err = ctx->codec->read_unit(ctx, unit);
>          if (err == AVERROR(ENOSYS)) {
>              av_log(ctx->log_ctx, AV_LOG_VERBOSE,
>                     "Decomposition unimplemented for unit %d "
> -                   "(type %"PRIu32").\n", i, frag->units[i].type);
> +                   "(type %"PRIu32").\n", i, unit->type);
>          } else if (err < 0) {
>              av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to read unit %d "
> -                   "(type %"PRIu32").\n", i, frag->units[i].type);
> +                   "(type %"PRIu32").\n", i, unit->type);
>              return err;
>          }
>      }
> @@ -277,6 +281,7 @@ int ff_cbs_write_fragment_data(CodedBitstreamContext *ctx,
>                     "(type %"PRIu32").\n", i, unit->type);
>              return err;
>          }
> +        av_assert0(unit->data && unit->data_ref);
>      }
>  
>      av_buffer_unref(&frag->data_ref);
> @@ -287,6 +292,7 @@ int ff_cbs_write_fragment_data(CodedBitstreamContext *ctx,
>          av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to assemble fragment.\n");
>          return err;
>      }
> +    av_assert0(frag->data && frag->data_ref);

You can remove the assert in ff_cbs_write_packet() if you add this one.

>  
>      return 0;
>  }
> diff --git a/libavcodec/cbs.h b/libavcodec/cbs.h
> index 402eb39e00..487358afaf 100644
> --- a/libavcodec/cbs.h
> +++ b/libavcodec/cbs.h
> @@ -84,8 +84,9 @@ typedef struct CodedBitstreamUnit {
>       */
>      size_t   data_bit_padding;
>      /**
> -     * If data is reference counted, a reference to the buffer containing
> -     * data.  Null if data is not reference counted.
> +     * A reference to the buffer containing data.
> +     *
> +     * Must be set if data is not NULL.
>       */
>      AVBufferRef *data_ref;
>  
> @@ -130,8 +131,9 @@ typedef struct CodedBitstreamFragment {
>       */
>      size_t data_bit_padding;
>      /**
> -     * If data is reference counted, a reference to the buffer containing
> -     * data.  Null if data is not reference counted.
> +     * A reference to the buffer containing data.
> +     *
> +     * Must be set if data is not NULL.
>       */
>      AVBufferRef *data_ref;

LGTM.


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