Realtime H264 decoding library for iOS.
This is a very low level component that is intended to process raw H264 frames for realtime video playback or processing.
- Create a
StreamParser(Choose length of your incoming stream header code length - 3 or 4 bytes) - Parse your data into raw (stripped) NALU frames
- Create an
H264Decoder - Decode an H264 frame to an
AviosImage. TheAviosImageis the rendered picture. This is a shared buffer in main memory. - Copy the main memory buffer to GPU memory. You can also optionally copy the data to a some other context such as a
UIImage. Or you can try to wrap aCGContextaround the shared memory. I've tried a few different things but found that the most efficient and stable way is to use the GPU for displaying the picture. I suggest trying GPUImage to help with rendering.
Step 2, 3 and 4 are then repeated over and over again to render and display the video. The framerate and syncing is entirely up to you to manage.
There are many H264 video stream formats such as RTP and AnnexB.
Curently, Stream Parser supports AnnexB with 3 or 4 length header codes. you can use it to prepare the stream for decoding. Otherwise, it is your responsibility to parse the stream and extract the frames. The Avios decoder only cares about the raw frames. A H264 frame is also called a NALU.
There's a lot of documents online about NALU stream such as AnnexB but here's a start:
http://stackoverflow.com/a/24890903/424124
http://stackoverflow.com/a/20686267/424124
Josh Baker @tidwall
Aviad Sachs @zaxy78
Avios source code is available under the MIT License