diff options
Diffstat (limited to 'internal/audio/gemini_provider.go')
| -rw-r--r-- | internal/audio/gemini_provider.go | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/internal/audio/gemini_provider.go b/internal/audio/gemini_provider.go index 74478bd..3b2872a 100644 --- a/internal/audio/gemini_provider.go +++ b/internal/audio/gemini_provider.go @@ -20,7 +20,8 @@ import ( const ( defaultGeminiTTSModel = "gemini-2.5-flash-preview-tts" geminiTTSLanguageCode = "bg" - geminiTTSChannels = 1 + // Gemini returns mono PCM; we upsample to stereo so both channels carry audio. + geminiTTSChannels = 2 geminiTTSSampleRate = 24000 geminiTTSBitsPerSample = 16 ) @@ -230,7 +231,25 @@ func ensureOutputDirectory(outputFile string) error { return nil } +// monoToStereo duplicates each 16-bit mono sample into both left and right +// channels, producing interleaved stereo PCM. The output is twice as large. +func monoToStereo(mono []byte) []byte { + bytesPerSample := geminiTTSBitsPerSample / 8 + stereo := make([]byte, len(mono)*2) + for i := 0; i+bytesPerSample <= len(mono); i += bytesPerSample { + sample := mono[i : i+bytesPerSample] + // Write sample for left channel, then right channel. + dst := i * 2 + copy(stereo[dst:], sample) + copy(stereo[dst+bytesPerSample:], sample) + } + return stereo +} + func encodePCMAsWAV(pcmData []byte) ([]byte, error) { + // Gemini returns mono audio; convert to stereo so both speakers carry audio. + pcmData = monoToStereo(pcmData) + var buffer bytes.Buffer if _, err := buffer.WriteString("RIFF"); err != nil { |