The encoding of the audio data sent in the request.
All encodings support only 1 channel (mono) audio, unless the
audio_channel_count and
enable_separate_recognition_per_channel fields are set.
For best results, the audio source should be captured and
transmitted using a lossless encoding (FLAC or LINEAR16).
The accuracy of the speech recognition can be reduced if lossy
codecs are used to capture or transmit audio, particularly if
background noise is present. Lossy codecs include MULAW,
AMR, AMR_WB, OGG_OPUS, SPEEX_WITH_HEADER_BYTE, and
MP3.
The FLAC and WAV audio file formats include a header that
describes the included audio content. You can request recognition
for WAV files that contain either LINEAR16 or MULAW
encoded audio. If you send FLAC or WAV audio file format in
your request, you do not need to specify an AudioEncoding; the
audio encoding format is determined from the file header. If you
specify an AudioEncoding when you send send FLAC or WAV
audio, the encoding configuration must match the encoding described
in the audio header; otherwise the request returns an
google.rpc.Code.INVALID_ARGUMENT][google.rpc.Code.INVALID_ARGUMENT]
error code.
