Use MediaCodec and MediaExtractor to decode and code video
android, android-mediacodec, bitmap, mediaextractor, video
Solution
You can find a collection of useful examples on the bigflake site.
In particular, the `ExtractMpegFramesTest` demonstrates how to decode a .mp4 file to `Bitmap`, and the `DecodeEditEncodeTest` decodes and re-encodes an H.264 stream, modifying the frames with a GLES shader.
Many of the examples use features introduced in API 18, such as `Surface` input to `MediaCodec` (which avoids a number of color-format issues), and `MediaMuxer` (which allows you to convert the raw H.264 elementary stream coming out of `MediaCodec` into a .mp4 file). Some devices will allow you to extract video to YUV data in `ByteBuffer`, modify it, and re-encode it, but other devices extract to proprietary YUV color formats that may be rejected by the API 16 version of `MediaCodec`.
I'd recommend coding for API 18 (Android 4.3 "Jellybean" MR2) or later.
Problem
I need to decode a video into a sequence of bitmaps, such that I am able to modify them, and then compress them back to a video file in android. I plan to manage this by using `getFrameAtTime` and saving it to an image sequence. Then I can modify images in the sequence and code it back to a movie. But I have two problem with this: - First, as I read it, the `getFrameAtTime` is for creating thumbnails and will not guarantee returning the correct frame. This makes the video laggy. - Secondly, saving the images and reading it back takes a long time. I read that the proper way of doing the decode is with MediaExtractor, this is fine, but I only have examples to render it directly to a `surfaceView`. Is there any way for me to convert the `outputBuffer` to a bitmap? I would need it to get it working with an api level of 16 and above.