alsa: fall back to 16 bit output

If the sample format isn't supported by the device (i.e. 24 bit on low-end sound chips), fall back to 16 bit output. There is code in pcm_utils.c which converts PCM data to 16 bit.

alsa: fall back to 16 bit output
ffed2fdc · Max Kellermann · 9b0693d8 · ffed2fdc
Commit ffed2fdc authored Oct 12, 2008 by Max Kellermann
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audioOutput_alsa.c src/audioOutputs/audioOutput_alsa.c +11 -0

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--- a/src/audioOutputs/audioOutput_alsa.c
+++ b/src/audioOutputs/audioOutput_alsa.c
@@ -194,6 +194,17 @@ configure_hw:
 	}

 	err = snd_pcm_hw_params_set_format(ad->pcmHandle, hwparams, bitformat);
+	if (err == -EINVAL && audioFormat->bits != 16) {
+		/* fall back to 16 bit, let pcm_utils.c do the conversion */
+		err = snd_pcm_hw_params_set_format(ad->pcmHandle, hwparams,
+						   SND_PCM_FORMAT_S16);
+		if (err == 0) {
+			DEBUG("ALSA device \"%s\": converting %u bit to 16 bit\n",
+			      ad->device, audioFormat->bits);
+			audioFormat->bits = 16;
+		}
+	}
+
 	if (err < 0) {
 		ERROR("ALSA device \"%s\" does not support %u bit audio: "
 		      "%s\n", ad->device, audioFormat->bits, snd_strerror(-err));