AESinkALSA: Open 5.1 Layouts according to CEA-861-D

[fritsch]

This will handle 5.1 Side and 5.1 Wide the same way. Which is okay according to the above spec.

[laurimyllari]

Tested on top of OE adb0cf1 and now 5.1 source is output as 5.1.

[fritsch]

v2: Don't influence bitstream passthrough. v1 also influence channel numbers of DTS-HD / TrueHD / EAC3

@laurimyllari: Thanks for testing, please redo if you find time.

[FernetMenta]

Now if engine requests FL/FR/FC/LFE/SL/SR you return FL/FR/FC/BL/BR/LFE, right? This will work but also force the engine through the process of rematrixing/mixing. You could save those extra cycles by returning the channels requested: FL/FR/FC/SL/SR/LFE

[fritsch]

According to the Spec I could return something like: FL/FR/FC/RL/RR/LFE to get the ball back to the Engine. Basically this PR makes clear, that according to the spec SL/SR and BR/BL are equivalent if only one pair of them is requested.

Edit: if only SL/SR are requested but BR/BL is missing and returns the minimal layout.

[FernetMenta]

If you return BL/BR if SL/SR is requested, this causes a lot of extra cycles. Just return the pair which is requested on that position.

[fritsch]

Wait, to make that fully correct:

If someone requests:
FL/FR/FC/LFE/SL/SR i return FL/FR/BL/BR/FC/LFE which is a 5.1 alsa channel map.

static enum AEChannel ALSAChannelMap[ALSA_MAX_CHANNELS + 1] = {
  AE_CH_FL      , AE_CH_FR      , AE_CH_BL      , AE_CH_BR      , AE_CH_FC      , AE_CH_LFE     , AE_CH_SL      , AE_CH_SR      ,
  AE_CH_UNKNOWN1, AE_CH_UNKNOWN2, AE_CH_UNKNOWN3, AE_CH_UNKNOWN4, AE_CH_UNKNOWN5, AE_CH_UNKNOWN6, AE_CH_UNKNOWN7, AE_CH_UNKNOWN8, /* for p16v devices */
  AE_CH_NULL
};

If you see in the code, we land at position 8: AE_CH_SR which would mean to open a 7.1 layout, the patch reduces the 8 to 6 and therefore opens a layout with 5.1.

This is how Alsa defines the channel layouts. If I return you something "non alsa like" I have to remap them later in the sink, which also causes a lot of extra cycles at a position where we don't want them.

[laurimyllari]

Works nicely as far as I can tell. I had problems with DTS-HD/MA, but that seems to be a Haswell issue (audio device got stuck) that I've seen on previous versions too.

Tried 5.1 PCM, ac3/dts passthrough, TrueHD and 5.1 FLAC.

[fritsch]

v3: Return SL/SR at the position of BL/BR which saves us the cycles and is also valid.

@FernetMenta: Thx much for helping with that one: http://imalbum.aufeminin.com/album/D20070912/338700_OP2IONTWQ13SZKS3733VBU38BQZ6LS_brett-vorm-kopf_H144817_L.jpg

Second patch is an alternative implementation which gets rid of the +5 which could harm, when the map changes. Open for discussion.

[fritsch]

jenkins build this please

[wsnipex]

jenkins build this please
@Memphiz can you please check why fritsch can't trigger jenkins?

[Memphiz]

He successfully triggered a build - see

http://jenkins.xbmc.org/view/helpers/job/XBMC-BuildMulti-PR/642/

But while building or after that he force pushed to his repo which removes the indicators from the PR.

[fritsch]

jenkins build this please sorry for force push and the 0xFFF changes you had to see today.