Support for 32bit audio WAV files

[Fireblend]

Issue description

I'm having trouble getting 32bit WAV audio files (sample provided below) to play using a regular ExtractorMediaSource. I always get an UnrecognizedInputFormatException with the "None of the available extractors (MatroskaExtractor, FragmentedMp4Extractor, Mp4Extractor, Mp3Extractor, AdtsExtractor, Ac3Extractor, TsExtractor, FlvExtractor, OggExtractor, PsExtractor, WavExtractor) could read the stream." message.

I can play these audio files with a regular AudioTrack by specifying the AudioFormat as PCM_FLOAT per Android's developer reference, which suggests there is native support for the file on Android, however, I've had no such luck with ExoPlayer.

Additionally, I found ticket #1246 which confirms there is support for 16bit and 24bit WAV audio files, however I can't find anything about 32bit audio support and would like clarification on whether ExoPlayer supports it or not.

Reproduction steps

Just attempt to play the file using a regular ExtractorMediaSource. I have a project which showcases this issue at this location:
https://github.com/Fireblend/exoTest

It contains an audiotrackApp module which showcases the file playing as expected with Audiotrack, and an exoApp module in which the failure to play the file with a regular ExtractorMediaSource is demonstrated.

Link to test content

https://github.com/Fireblend/exoTest/raw/master/Exotest/exoApp/src/main/res/raw/th_oial_32_float_48khz.wav

Version of ExoPlayer being used

r2.1.1

Device(s) and version(s) of Android being used

Motorola X Play, Android 6.0
Nexus 5, Android 6.0

A full bug report captured from the device

I suspect this isn't needed, but I'm attaching one anyway.
bugreport.txt

Thanks in advance!

[andrewlewis]

To support extracting this file, we need to update WavExtractor to handle format 3 (float), outputting a track with PCM float encoding.

For playback of the float track, I'm currently adding support for 32-bit float output (similar to #2517), which can be used by setting a flag when using FfmpegAudioRenderer. We could add an equivalent flag to MediaCodecAudioRenderer to output PCM float directly.

Alternatively, we could update ResamplingAudioProcessor to convert 32-bit float to 16-bit integer PCM, which would be lossy but has the advantage that audio processors could still be applied to the input.

[stefanomemrise]

is there any progress on this? any ETA? thanks