v1.2.0

• VideoFrames.decodeAudio(path): a file's audio as 16-bit PCM (PcmAudio), at its own rate and channels; null when it has no sound.
• VideoWriter.create(audio: ...): encode PCM to AAC in the output, instead of copying another file's track.
• VideoFrames.concat(inputs, output): join MP4s of the same format without re-encoding; clips of another format throw writeFailed.