Class AudioEncoding (2.28.1)

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AudioEncoding(value)

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, MP3, and WEBM_OPUS.

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.

Enums
Name	Description
ENCODING_UNSPECIFIED	Not specified.
LINEAR16	Uncompressed 16-bit signed little-endian samples (Linear PCM).
FLAC	`FLAC` (Free Lossless Audio Codec) is the recommended encoding because it is lossless--therefore recognition is not compromised--and requires only about half the bandwidth of `LINEAR16`. `FLAC` stream encoding supports 16-bit and 24-bit samples, however, not all fields in `STREAMINFO` are supported.
MULAW	8-bit samples that compand 14-bit audio samples using G.711 PCMU/mu-law.
AMR	Adaptive Multi-Rate Narrowband codec. `sample_rate_hertz` must be 8000.
AMR_WB	Adaptive Multi-Rate Wideband codec. `sample_rate_hertz` must be 16000.
OGG_OPUS	Opus encoded audio frames in Ogg container (`OggOpus
SPEEX_WITH_HEADER_BYTE	Although the use of lossy encodings is not recommended, if a very low bitrate encoding is required, `OGG_OPUS` is highly preferred over Speex encoding. The `Speex
MP3	MP3 audio. MP3 encoding is a Beta feature and only available in v1p1beta1. Support all standard MP3 bitrates (which range from 32-320 kbps). When using this encoding, `sample_rate_hertz` has to match the sample rate of the file being used.
WEBM_OPUS	Opus encoded audio frames in WebM container (`OggOpus