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Old 29th April 2015, 12:36   #69  |  Link
hello_hello
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Quote:
Originally Posted by Ghitulescu View Post
It is a behaviour at you NOT TO understand what is written. I mean to try to twist what has been said in order to make you like having right when you're obviously wrong.
I understand exactly what's written and I don't need to try to twist anything.
I'm fully aware you had to convert the 4.1ch audio to 5.1ch. I never said you didn't. I just don't know why it requires references to Microsoft when you're using a hardware player and it's got nothing to do with the topic. It's just you once again dragging a thread off on a tangent because you like to pretend you know what you're talking about and you thought my references to the wave file format was an opportunity to display how clever you think you are, only once again you didn't understand what was being said and the result was another of your tangents.
Stating I'm obviously wrong is hilarious coming from you when you've ignored almost entire posts in this thread because they've proved you wrong.

Quote:
Originally Posted by Ghitulescu View Post
Table 42 reads, for 4 channels, the following and only configuration
4 ¦ 4 ¦ single_channel_element(center front speaker), channel_pair_element(left, right center front speakers), single_channel_element(rear surround).

So it's a 3 center front-speakers and a single rear one configuration. Hardly a real-life configuration (unless one implements true L and R to be stored as LFC and RFC). This is how I read them.
I am not sure this configuration has anything to do with your expectations of a 3.1 configuration (most probably L, R, C and LFE).
Foobar2000 displays 4.0ch audio consisting of a front centre channel, front left and right channels, and a rear centre channel.
Whether it's labelled as rear centre or rear surround I don't see how it's any different to 3.1ch except there's a rear centre channel instead of a LFE channel. It's specified as two single channel elements and one channel pair element, a configuration you said wasn't allowed because only one unpaired SCE was allowed.

Quote:
Originally Posted by Ghitulescu View Post
But this are the implicit/default matrixes. In other words, if you send a 4-substreams file to any AAC-encoder that encoder has to use the default matrix (table 42) to assign the channels.
If you don't want this stupid 4-chn matrix you have to use a custom assignment, as per clause 8.5.3.2.
So it can use the stupid 4ch matrix despite your claim there can only be one unpaired single channel, or is that somehow still true even while we talk about the 4ch configuration with two unpaired SCEs?

Quote:
Originally Posted by Ghitulescu View Post
Any SCE’s except the last SCE must be paired, and the presence of exactly two SCE’s (alone or preceeded by a CPE) indicates that the two SCE’s are Left and Right Rear center, respectively.
Let's include the part of 8.5.3.2 you ignored because it didn't suit you.

Quote:
Included in the PCE are “list of front channels”, using the rule center outwards, left before right. In this list, a center channel SCE, if any, must come first, and any other SCE’s must appear in pairs, constituting an LR pair.

After the list of front channels, there is a list of “side channels” consisting of CPE’s, or of pairs of SCE’s. These are listed in the order of front to back. Again, in the case of a pair of SCE’s, the first is a left channel, the second a right channel.

After the list of side channels, a list of back channels is available, listed from outside in. Any SCE’s except the last SCE must be paired, and the presence of exactly two SCE’s (alone or preceeded by a CPE) indicates that the two SCE’s are Left and Right Rear center, respectively.
Obviously you can start with a non-paired SCE and end with a non-paired SCE and every time I add one single SCE to another single SCE I get two single SCEs. Didn't you say there could only be one?
The default 4ch matrix follows the rule exactly as described. Unpaired SCE (centre), paired SCE(L&R), unpaired SCE (rear).

Quote:
Originally Posted by Ghitulescu View Post
So, you may have: CPEs (already paired) and paired SCEs but only the last SCE in the list may be a "bachelor" (usually LFE).
Because LFE always was a single channel (since Dolby implemented it in 1991).
The AAC spec clearly distinguishes between a LFE and a SCE so the last SCE in the chain is not assumed to be an LFE channel. That's just something new you've made up. Only a LFE channel is assumed to be an LFE channel.
You only have to think about 5.1ch audio for ten seconds to see your claim makes no sense. Front LR is a pair, rear LR is a pair, the LFE channel is unpaired, so where does that leave the centre channel when there can't be another unpaired SCE? Obviously 3.1ch is the same as 5.1ch with a pair of SCEs removed. How then can 3.1ch not be allowed??

Quote:
Other elements are also specified. A list of one or more LFE’s is specified for application to this program.
Quote:
Originally Posted by Ghitulescu View Post
Why this strange pairing? For encoding economy - in short, pair channels may be encoded as MS (Mid+Side), known as joint stereo in MP3.
Single channels are reserved for channels carrying important information, like L and R, although they can also be present as a pair (probably to allow an even lower bitrate).
You sure you're not making it up as you go again? Why have SCEs if they're going to be encoded as joint stereo? It seems more likely that the definition of a pair of SCEs encoded using joint stereo would be a CPE.
And why can't you encode important channels like L and R using joint stereo? Wouldn't that kind of be the point of it?

Last edited by hello_hello; 29th April 2015 at 19:26. Reason: spelling
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