audio.h: add ENCODING_IEC61937

Add audio_has_proportional_frames() to replace
audio_is_linear_pcm() in some cases.

Bug: 24541671
Bug: 20891646
Bug: 26373761
Change-Id: I2ec12068b18bfe46213b79c274a59bfeba884157
Signed-off-by: Phil Burk <philburk@google.com>
1 file changed