#android #codec #bindings #multimedia #ffi #audio-video

mediacodec

Rust bindings to MediaCodec, with an easy-to-use API

3 releases

0.1.2 Jan 9, 2022
0.1.1 Jan 8, 2022
0.1.0 Jan 7, 2022

#254 in Video

MIT license

81KB
1.5K SLoC

Rust MediaCodec

This library provides Rust bindings to the Android MediaCodec APIs. It also adds some pretty nifty utilities to make working with buffers on Android easier.

Features Currently Implemented

  • MediaCodec
  • MediaExtractor
  • MediaMuxer
  • MediaFormat
  • Safe codec buffers abstraction
  • Some extra utilities to make working with the library easier

Some Decoding example:

use log::debug;
use mediacodec::{Frame, MediaCodec, MediaExtractor, SampleFormat, VideoFrame};

#[no_mangle]
extern "C" fn process() {
    let mut extractor = MediaExtractor::from_url("/path/to/a/resource").unwrap();

    debug!("Track count: {}", extractor.track_count());

    let mut decoders = vec![];

    for i in 0..extractor.track_count() {
        let format = extractor.track_format(i).unwrap();
        debug!("{}", format.to_string());
        let mime_type = format.get_string("mime").unwrap();
        let mut codec = MediaCodec::create_decoder(&mime_type).unwrap();

        codec.init(&format, None, 0).unwrap();

        codec.start().unwrap();
        decoders.push(codec);
        extractor.select_track(i);
    }

    while extractor.has_next() {
        // 1. Get the track index
        let index = extractor.track_index();

        if index < 0 {
            break;
        }

        let codec = &mut decoders[index as usize];

        // Fetch the codec's input buffer
        while let Ok(mut buffer) = codec.dequeue_input() {
            if !extractor.read_next(&mut buffer) {
                debug!(
                    "MediaExtractor.read_next() returned false! has_next(): {}",
                    extractor.has_next()
                );
                break; // VERY IMPORTANT, there's nothing else to DO, so break!!!
            }

            // When the buffer gets dropped (here), the buffer will be queued back to MediaCodec
            // And we don't have to do anything else
        }

        // Check for output
        let output_fmt = codec.output_format().unwrap();
        while let Ok(mut buffer) = codec.dequeue_output() {
            if let Some(ref frame) = buffer.frame() {
                match frame {
                    Frame::Audio(value) => match value.format() {
                        SampleFormat::S16(_) => {
                            // Do something with the audio frame
                        }
                        SampleFormat::F32(_) => {
                            // Do something with the audio frame
                        }
                    },
                    Frame::Video(value) => match value {
                        VideoFrame::Hardware => {
                            // Nothing TODO. The frame will be rendered
                        }
                        VideoFrame::RawFrame(_) => {
                            // Read out the raw buffers or something
                        }
                    },
                }
            }

            // Set the buffer to render when dropped. Only applicable to video codecs that have a hardware buffer (i.e, attached to a native window)
            buffer.set_render(true);
        }
    }
}

You can find some more examples in the examples directory.

Dependencies

~0–1MB
~11K SLoC