feat(pipe): add audio_output_pipe_passthrough to write the raw encoded stream#316
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JRpersonal wants to merge 1 commit into
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feat(pipe): add audio_output_pipe_passthrough to write the raw encoded stream#316JRpersonal wants to merge 1 commit into
JRpersonal wants to merge 1 commit into
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…d stream Add a passthrough mode to the pipe backend: with audio_output_pipe_passthrough the decoder is bypassed and the raw Ogg/Vorbis bitstream is written to the pipe untouched, so a downstream consumer (e.g. a hardware decoder) does the decoding. Motivation: on a weak ARM target that can decode Vorbis natively, decoding to float32 PCM in go-librespot and re-streaming PCM wastes CPU and bandwidth. Handing the original Ogg/Vorbis straight through roughly halves CPU there. What it changes: - New config option audio_output_pipe_passthrough (cli + daemon Config), and a Passthrough flag on the pipe output, validated as pipe-backend only. - New AudioSourcePassthrough interface (ReadBytes) in output.go. - passthroughSource (player): hands out a track's raw Ogg bytes; position is approximated from bytes consumed and SetPositionMs only supports a restart (a mid-page byte seek would corrupt the Ogg stream). - SwitchingAudioSource.ReadBytes concatenates consecutive tracks' raw streams into a chained Ogg bitstream the downstream decoder plays continuously. - player NewStream: for OGG_VORBIS, when passthrough is on, skip vorbis.New and feed the raw audio stream through passthroughSource. - pipeOutput.passthroughLoop writes the raw bytes (no decode, no volume, no format transform). Caveats: volume scaling and normalisation/replay-gain are not applied in passthrough (the stream is untouched); seeking is limited to a restart; pipe backend only; FLAC passthrough is not included.
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Adds a passthrough mode to the pipe backend: with
audio_output_pipe_passthroughthe decoder is bypassed and the raw Ogg/Vorbis bitstream is written to the pipe untouched, so a downstream consumer (e.g. a hardware decoder) does the decoding.Motivation: on a weak ARM target that can decode Vorbis natively, decoding to float32 PCM in go-librespot and re-streaming PCM wastes CPU and bandwidth. Handing the original Ogg/Vorbis straight through roughly halves CPU there.
What it changes:
audio_output_pipe_passthrough(cli + daemon Config), and aPassthroughflag on the pipe output, validated as pipe-backend only.AudioSourcePassthroughinterface (ReadBytes) inoutput.go.passthroughSource(player): hands out a track's raw Ogg bytes; position is approximated from bytes consumed andSetPositionMsonly supports a restart (a mid-page byte seek would corrupt the Ogg stream).SwitchingAudioSource.ReadBytesconcatenates consecutive tracks' raw streams into a chained Ogg bitstream the downstream decoder plays continuously.NewStream: forOGG_VORBIS, when passthrough is on, skipvorbis.Newand feed the raw audio stream throughpassthroughSource.pipeOutput.passthroughLoopwrites the raw bytes (no decode, no volume, no format transform).Caveats: volume scaling and normalisation/replay-gain are not applied in passthrough (the stream is untouched); seeking is limited to a restart; pipe backend only; FLAC passthrough is not included.
Builds clean on current
master. Happy to adjust naming or split the change if you'd prefer.