What is the fastest way to decode an MP3 file then encode to AAC on Android?

Question

I have a working solution using MediaCodec and MediaExtractor, but the decoding of a 6mb MP3 takes 15 sec + encoding of 15 sec to AAC. Total of > 30 sec. I need something really fast <10 sec. Anyone know a faster solution?

EDIT

My bottleneck is from the Mediacodec itself. The bytebuffer they provide is too small. When setting up MediaFormat to AAC the InputBytebuffers are only 4096 bytes at a time is too slow for me. Its good for streaming but not for File to File.

I switch to a C lib decoder that decode in 3 sec instead of 15 sec. But the encoder still take 15 sec. Anyone has a C lib AAC encoder that can also add ADTS Headers?

Answer 1

It sounds like you first decode the full file, then encode it. It might end up faster if you do these at the same time, i.e. when you have enough output data from the decoder to provide a full input frame to the encoder, pass it in. This can help with some parallelism, but I doubt that it helps enough to get the speedup you want.