[Matroska-devel] CodecSpecs

Santiago Jimeno sjimeno at ya.com
Mon Jan 10 02:24:08 CET 2011


Thank you Moritz for the answer

Regarding MLP-TrueHD, I made what you tell me in your e-mail, but without 
success.
MLP contain in the blocks the whole header beginning with F8726FBB, but 
TrueHd doesn't contain the first 4 bytes of the header (F8726FBA).
And supposing that the first bytes of the file or the block are part of the 
header (stripped), it doesn't coincide with the data given before by MKV 
file in TrackEntry.
On the other hand the header format of both, although similar, is not same. 
Maybe I have mistaken the data of TrueHd header format.

The samples that I am using are:
http://samples.mplayerhq.hu/A-codecs/TrueHD/TrueHD%20Sample%201%20(Final%20Fantasy%20VII%20Advent%20Children).mkv
http://samples.mplayerhq.hu/A-codecs/TrueHD/TrueHD%20Sample%202%20(Evangelion%201.11%20You%20Are%20(Not)%20Alone).mkv

I have observed that you with Mkvtool can calculate the duration of 
MLP-TrueHd audio file to make the MKA file.
It has been impossible for my to calculate the duration with the data 
provided by the original audio file.
Would you be able to help me in this?

Regards. Santiago

----- Original Message ----- 
From: "Moritz Bunkus" <moritz at bunkus.org>
To: "Discussion about the current and future development of Matroska" 
<matroska-devel at lists.matroska.org>
Sent: Sunday, January 09, 2011 6:33 PM
Subject: Re: [Matroska-devel] CodecSpecs


> Hey,
>
> On Thu, 6 Jan 2011 00:01:45 +0100, "Santiago Jimeno" <sjimeno at ya.com>
> wrote:
>
>> AC3 and EAC3 in SymplyBlock (A3): follow ATSC a_52 - 2010
>> specifications. My error is that I waited that audio code was in the
>> first track of the cluster, but it doesn't always happen this way.
>
> Yes.
>
>> Quicktime in Private data: follows MP4 specifications of stsd atom.
>> But QDMC from AudioSampleEntry with size (4 bytes) and format (4 char)
>> before, and QDM2 from frma box (52 bytes later).
>
> Sounds about right.
>
>> DTS in SymplyBlock (A3): adds the whole header with included syncword
>> (HD also).
>
> True.
>
>> New problem:  MLP and TrueHd
>> MLP: includes complete Header in SymplyBlock. But it doesn't add more
>> data than the content in TrackEntry.
>> TrueHd:  impossible for my to find the relationship between the data
>> of SymplyBlock and the specifications.
>
> MLP and TrueHD are handled the same way. They contain the whole header
> in the blocks.
>
>> Does somebody have an audio sample of TrueHd?
>
> http://www.bunkus.org/mtx-test-data/vob/vc1_truehd_eac3.evo contains
> TrueHD and EAC3 audio tracks. If you don't know how to demux the TrueHD
> track from it then merge with mkvmerge and extract the TrueHD track from
> the resulting Matroska file with mkvextract.
>
> Regards,
> mosu
>
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