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

[Mark Thompson]

On 01/05/18 16:51, James Almer wrote:
> 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.

Yes, that would be sensible - removed.

>>  
>>      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.

And applied.

Thanks,

- Mark