[pulseaudio-discuss] HDMI audio passthrough no longer working

Alexander E. Patrakov patrakov at gmail.com
Mon Mar 9 03:58:07 PDT 2015

09.03.2015 15:11, Thomas Martitz wrote:
> Am 08.03.2015 um 12:42 schrieb Alexander E. Patrakov:
>> But, why are you using the passthrough mode at all? HDMI, unlike
>> SPDIF, has enough bandwidth to pass the 7.1 PCM stream. For SPDIF,
>> passthrough was a necessity due to this bandwidth limitation. For real
>> HDMI (as opposed to HDMI-to-SPDIF converter that doesn't support
>> multichannel PCM anyway), it only serves marketing purposes (i.e., in
>> theory, provides no benefits over software decoding and sending the
>> resulting multichannel PCM stream). I sometimes think that the proper
>> fix is to disallow passthrough completely for multichannel HDMI
>> profiles, i.e. to effectively hide the checkboxes that you have
>> demonstrated on the screenshot.
> 1) You might want to decode Dolby Digital / DTS on an external receiver
> because decoding on the PC requires a license.

Does not apply here - Xamindar is already willing to install Kodi and 
VLC, products that include the decoder. But yes, theoretically, due to 
bad laws in some countries, it is valid there.

> 2) Receivers might only accept spdif-data (plain stereo or encoded)
> regardless of HDMI's theoretical capabilities.

Also does not apply here (but yes, it does apply if a TV is connected 
via HDMI, and the receiver is connected to that TV via SPDIF, and the TV 
does not have a built-in AC3 or DTS encoder). By selecting a 
multichannel profile, Xamindar has already indicated that his receiver 
is not of this variety.

> If PA is actually unable to pass through in multichannel profiles, then
> yes, pavucontrol should not show the check boxes, or better yet grey
> them out with a "Change to stereo profile" tooltip.

I have already submitted a patch that hides these checkboxes. But it 
seems like Arun is going to work on a better solution, so let's wait and 
see the result :)

Alexander E. Patrakov

More information about the pulseaudio-discuss mailing list