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Topic: Is ffmpeg or fdk-aac support AAC metadata and apply DRC? (Read 1971 times) previous topic - next topic
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Is ffmpeg or fdk-aac support AAC metadata and apply DRC?

I've revised FDK-AAC and embedded DRC value in metadata and encoded an AAC stream.
But I found it was invalid when I used ffmpeg for decoding this stream, there was nothing changed in Audio gain value.

I confirmed DRC data already embedded in AAC stream, so what do you guys think of this problem? Thanks a lot.

Main revision as below:
(1)fdk-aac\libAACenc\src\aacenc_lib.cpp, modified below flag.
            config->userMetaDataMode   = 1;
  (2)  fdk-aac\libAACenc\src\metadata_main.cpp,modified below default setting.
  static const AACENC_MetaData defaultMetaDataSetup = {
         AACENC_METADATA_DRC_MUSICSTANDARD, //AACENC_METADATA_DRC_NONE,
         AACENC_METADATA_DRC_MUSICSTANDARD, //AACENC_METADATA_DRC_NONE,
         -(31<<16),
         -(31<<16),
         1, //0,
          .....
        };

Re: Is ffmpeg or fdk-aac support AAC metadata and apply DRC?

Reply #1
I've revised FDK-AAC and embedded DRC value in metadata and encoded an AAC stream.
But I found it was invalid when I used ffmpeg for decoding this stream, there was nothing changed in Audio gain value.

I confirmed DRC data already embedded in AAC stream, so what do you guys think of this problem? Thanks a lot.

ffmpeg's native AAC decoder does not support DRC metadata for AAC (they are parsed, but just thrown away).
You can download samples from https://www2.iis.fraunhofer.de/AAC/metadata.html and test yourself.


 
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