search for: channel_type

> True, but remember that the channel map type implied the number of > entries in the table, and also that in this organization you'll always > number the logical channels consequtively since each logical channel > indeed corresponds to an index into the array. If the channel map type > says it's a map for 5.1, there will only be 6 slots in the table no > matter how

...me if I'm wrong. What we're proposing is to define the channel map for each supported channel group type. The array syntax I used in my last post probably added to the confusion - look at it again but without using the assigned values to the OGG_CHANNEL_* text. A couple examples: Packet 1: channel_type = OGG_CHANNEL_MAP_5_1 channel_map [0 = OGG_CHANNEL_FRONT_LEFT] = 1 channel_map [1 = OGG_CHANNEL_FRONT_CENTER] = 2 channel_map [2 = OGG_CHANNEL_FRONT_RIGHT] = 3 Packet 2: channel_type = OGG_CHANNEL_MAP_STEREO channel_map [0 = OGG_CHANNEL_FRONT_LEFT] = 1 channel_map [1 = OGG_CHANNEL_FRONT_RIGHT] = 2...

...t;interleaving order. >> I that this is handled pretty nicely by the "simple map" that Sampo suggested. This is basically the same thing as the "channel map" described on the wiki, but with the (physical,logical) channel pair swapped. So, using the syntax from the wiki: channel_type = OGG_CHANNEL_MAP_STEREO channel_map [OGG_CHANNEL_FRONT_LEFT] = 1 channel_map [OGG_CHANNEL_FRONT_RIGHT] = 2 This is nice because it makes it impossible for somebody to do something stupid like define two channels as carrying FRONT_LEFT. A player can't handle that situation sanely, but handli...

> Yes. Channel map type tells us what the primary interpretation of the > stored signals is. Channel definitions are there to tell which stored > channel corresponds to which abstract channel in the type. Channel > conversions define downmixes to secondary formats, as they do in MLP, > and might end up being ignored unlike the channel map. I think the channel conversion will

...ef STEREO_L:=1; #def STEREO_R:=2; #def MAP_UHJ:=3; #def N_UHJ:=4; #def UHJ_SIGMA:=1; #def UHJ_DELTA:=2; #def UHJ_T:=3; #def UHJ_Q:=4; header:= (n_chn:=3; // three channels are stored maps:= ( (map_type:=simple; // no matrix, the most preferred choice channel_type:=MAP_UHJ; // implies that the map has N_UHJ==4 entries map[UHJ_SIGMA]:=1; // SIGMA is stored in the first physical channel map[UHJ_DELTA]:=2; map[UHJ_T]:=3; map[UHJ_Q]:=0;), // the fourth channel is not physically present (map_type:=complex; //...

Sampo Syreeni wrote: > Secondly, I'd like to see the channel map fleshed out in more detail. Sampo, I did flesh out the wiki a **little** more. Is the intent clearer now? > (Beware of the pet peeve...) What is that pet peeve? > IMO the mapping should cover at least the > channel assignments possible in WAVE files, the most common Ambisonic > ones, and perhaps some added

...as well. Since nobody seemed too interested but didn't object to my suggestion of helping out either, I went ahead and added a proposed channel mapping section, to see if I can get some discussion going that way. I haven't disturbed the existing channel map section, eventhough it lacks channel_type definitions, and I've tried to keep my changes conservative otherwise. Apparently you noticed my changes right after I made them, and before I had time to ask for comments on-list. Against that background, do you have suggestions wrt to the channel map section? What I've tried to do is...

Hi, The Xiph Wiki contains the four pages: OggPCM OggPCM Draft1 (with Talk page) OggPCM Draft2 OggPCM Draft3 Can I suggest that this be reduced to just one (or maybe two) pages. I suggest this because somebody has started making changes to OggPCM Draft2. My guess is that this is not desirable. Regards, Martin -- Martin J Leese E-mail: martin.leese@stanfordalumni.org Web:

> I that this is handled pretty nicely by the "simple map" that Sampo > suggested. This is basically the same thing as the "channel map" > described on the wiki, but with the (physical,logical) channel pair > swapped. So, using the syntax from the wiki: > channel_type = OGG_CHANNEL_MAP_STEREO > channel_map [OGG_CHANNEL_FRONT_LEFT] = 1 > channel_map [OGG_CHANNEL_FRONT_RIGHT] = 2 Not sure this is a good idea. Remember that channel_map is just an array (unless you want to make it a map?). So if you had a OGG_CHANNEL_SPECIAL with an id of 1000, it would force...