[Libav-user] Raw AAC decoding using only libavcodec

[Carl Eugen Hoyos]

2016-08-28 19:01 GMT+02:00 Christopher Snowhill <kode54 at gmail.com>:

>>> The code I am looking at now currently takes what the caller has
>>> determined to be either ADTS or ADIF formatted AAC, and passes it
>>> directly to libavcodec, via avcodec_decode_audio4. I assume this is
>>> incorrect, as it doesn't seem to be working for these formats.
>>
>> Are you using the (necessary) aac parser from libavcodec? Without it,
>> the decoder will not know where the aac frames start.
>
> I have no idea if he is using the parser. Is it more than merely
> constructing AVPackets and passing them directly to the decoder?

I can only repeat that if you do not process the input data with a
parser (and remember that a parser has nothing to do with a
demuxer), the decoder will not be able to decode the input data.

But I do not know if a parser is needed for your input data, I don't
think you mentioned where the input data comes from.

Note that FFmpeg's aac decoder (contrary to faad) is not able to
decode "raw" aac (which is very unusual, but it is not difficult to
produce samples), only adts.

Carl Eugen