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Topic: Parametric stereo in Matroska? (Read 6472 times) previous topic - next topic
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Parametric stereo in Matroska?

This is a question for ChristianHJW i guess.

I (rather sneakily) tried insetring the lowest file size file from Ivan's recent quick test into MKV knowing that it was probably the first couple of publicly available files using the new HE-AAC+PS, alas to no avail.

I then tried muxing it into an MP4 (assuming that it might have been raw data) using mp4UI which managed to produce a file (said something like aac profile 2) but didn't play.

I tried muxing a matroska file from that MP4, which again didn't work.

I guess this means it isn't in yet, but i'm kinda hoping that PS support will be added soon 'cause it's incredible.

I remeber we had to wait a little while for an SBR solution which i greatly appreciated so it will be great when it's supported.

Then again, if it's already supported then Kudos and could you tell me how to do it properly?

Edit: forgot to mention that i was muxing using mmg together with mkvmerge 0.85

Parametric stereo in Matroska?

Reply #1 –
These files use ADIF format - dunno if your AAC->MP4 conversion tool does support ADIF style AAC files.

Otherwise, there should be no problems with PS - new FAAD2 builds will automatically upmix everything to stereo - so PS would make no difference for the other parts of the decoding/playback process.

PS data is not signalled in MP4 container (and at this moment there are no plans to do so), so  there is no difference between SBR and PS+SBR  .mp4 file.

Parametric stereo in Matroska?

Reply #2 –
I see. So i don't have to worry huh? Thank you

Parametric stereo in Matroska?

Reply #3 –
mkvmerge can read .aac files also, same goes for avi-mux GUI, but im not sure if both could handle these tracks if their headers are 'special'. In any case, if the MP4 doesnt work, we cant expect that the MKA made from the MP4 will.

@ Ivan , menno : will current FAAD2 based decoders, like the fb2k plugin, CoreAAC or 3ivX, handle parametric stereo already ? Is there something special we have to write into the codec private for the correct decoder initialisation ? how can we find the info about parametric stereo in the AAC streams ?

Parametric stereo in Matroska?

Reply #4 –
PS signalling is implicit. FAAD2 will from now on simply upmix all mono files to stereo, even if it is not a PS file.

Menno

Parametric stereo in Matroska?

Reply #5 –
Something quite interesting i noted was that the mp4 muxer (mp4UI 1.0 beta 1) identified the tracks as having 5 channels... clearly there must be a problem with the muxer though 

Parametric stereo in Matroska?

Reply #6 –
Quote
will current FAAD2 based decoders, like the fb2k plugin, CoreAAC or 3ivX

3ivX is based on the CT decoder.

Parametric stereo in Matroska?

Reply #7 –
Quote
Quote
will current FAAD2 based decoders, like the fb2k plugin, CoreAAC or 3ivX

3ivX is based on the CT decoder.

No actually

3ivx's AAC decoder is derived from the ISO reference code, parts of the ISO reference code come from CT, so whether you want to refer to this as the CT decoder is up to you, but I wouldn't

Parametric stereo in Matroska?

Reply #8 –
Quote
PS signalling is implicit. FAAD2 will from now on simply upmix all mono files to stereo, even if it is not a PS file.

What about multichannel files using the same parametric channel coding? How does FAAD2 behave in this case?

Parametric stereo in Matroska?

Reply #9 –
Quote
multichannel files using the same parametric channel coding?
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That's impossible

Parametric stereo in Matroska?

Reply #10 –
Wait a second, did i hear you correctly? I know that parametric stereo currently only works on stereo pairs but does this rule out multichannel AAC using several PS pairs (i.e. front pair, back pair, centre + LF). I thought this was currently how multichannel AAC worked: a bunch of stereo pairs stuck together. Am i completely wrong? Does the latest Nero release support ps endoding yet? I'm in the middle of downloading it.

Parametric stereo in Matroska?

Reply #11 –
Quote
Wait a second, did i hear you correctly? I know that parametric stereo currently only works on stereo pairs but does this rule out multichannel AAC using several PS pairs (i.e. front pair, back pair, centre + LF). I thought this was currently how multichannel AAC worked: a bunch of stereo pairs stuck together. Am i completely wrong? Does the latest Nero release support ps endoding yet? I'm in the middle of downloading it.
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Using PS on multichannel files is technically possible, but standard forbids it. MPEG is working on a different solution for multichannel.
 

Parametric stereo in Matroska?

Reply #12 –
I have ever tried to mux x264 and HE-AAC-PS into a matroska container with mkvmerge and it plays.