On Tue, Jan 19, 2016 at 02:47:50PM +0100, Lars-Peter Clausen wrote:
On 01/12/2016 04:38 PM, Philipp Zabel wrote:
Exporting the ELD bytes to userspace allows an application to select an appropriate audio format depending on the current capabilities of the connected HDMI sink device.
This needs an explanation why this method, which will require explicit support in applications, should be used rather than the standard ALSA hardware capabilities reporting.
That can be summed up in one line:
ALSA doesn't know about all the different formats for compressed audio.
As far as I'm aware, applications today just lie to ALSA and use the "16-bit PCM audio" formats (SNDRV_PCM_FORMAT_S16_LE or SNDRV_PCM_FORMAT_U16_LE) to send compressed audio via ALSA, relying on the IEC controls to set the channel status data correctly.
Maybe it would be nice to add formats for DTS, DTS-HD, AC3, OBA, etc to the ALSA format list.