how to create AVPacket manually with encoded AAC data to send mpegts?

0
votes

I'm developing app which sends mpeg2ts stream using FFMPEG API.(avio_open, avformat_new_stream etc..)

The problem is that the app already has AAC-LC audio so audio frame does not need to be encoded because my app just bypass data received from socket buffer.

To open and send mpegts using FFMPEG, I must have AVFormattContext data which is created from FFMPEG API for encoder as far as I know.

Can I create AVFormatContext manually with encoded AAC-LC data? or I should decode and encode the data? The information I know is samplerate, codec, bitrate..

Any help will be greatly appreciated. Thanks in advance.

1
c++ffmpegaac

1 Answers

0
votes

Yes, you can use the encoded data as-is if your container supports it. There are two steps involved here - encoding and muxing. Encoding compress the data, muxing mixes it together in the output file, so the packets are properly interleaved. Muxing example in FFMpeg distribution helped me with this.

You might also take a look at the following class: https://sourceforge.net/p/karlyriceditor/code/HEAD/tree/src/ffmpegvideoencoder.cpp - this file is from one of my projects, and contains video encoder. Starting from the line 402 you'll see the setup for non-converted audio - it is kind of a hackish way, but it worked. Unfortunately I still end up reencoding audio because for my formats it was not possible to achieve frame-perfect synchronization which I needed