CRAS: fmt_conv: Support quad to 5.1 channel conversion

Add the logic to convert quad output to 5.1 surround by
copying the {front,rear} {left,right} of input to the {front,rear}
{left,right} of output respectively and fill others with zero.

BUG=b:183070810
TEST=1. `sox -n -c6 -b 16 -r 48000 /tmp/zero.raw synth 300 sine 0`
     2. `sox -n -c4 -b 16 -r 48000 /tmp/sine.raw synth 30 sine 300\
         sin 400 sin 500 sin 600`
     3. `cras_test_client -c6 -P /tmp/zero.raw`
     4. `cras_test_client -c4 -P /tmp/sine.raw` at the same time.
     5. Verified that each of the 4 chanel are are output with the
         correct tone with a 6 channel audio device.
TEST=`FEATURES=test USE=asan emerge-${BOARD} adhd`

Change-Id: I12784c3ff38da1d30994d0711ce0630e009775a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/2771463
Commit-Queue: Judy Hsiao <judyhsiao@chromium.org>
Commit-Queue: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Tested-by: Judy Hsiao <judyhsiao@chromium.org>
Auto-Submit: Judy Hsiao <judyhsiao@chromium.org>
Reviewed-by: Yu-Hsuan Hsu <yuhsuan@chromium.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/cras/src/server/cras_fmt_conv_ops.h b/cras/src/server/cras_fmt_conv_ops.h
index a1a57487..0af7564b 100644
--- a/cras/src/server/cras_fmt_conv_ops.h
+++ b/cras/src/server/cras_fmt_conv_ops.h
@@ -46,6 +46,13 @@ size_t s16_stereo_to_51(size_t left, size_t right, size_t center,
 			const uint8_t *in, size_t in_frames, uint8_t *out);
 
 /*
+ * Channel converter: quad to 5.1 surround.
+ */
+size_t s16_quad_to_51(size_t font_left, size_t front_right, size_t rear_left,
+		      size_t rear_right, const uint8_t *in, size_t in_frames,
+		      uint8_t *out);
+
+/*
  * Channel converter: 5.1 surround to stereo.
  */
 size_t s16_51_to_stereo(const uint8_t *in, size_t in_frames, uint8_t *out);