gmane.comp.multimedia.matroska.devel

Re: Problem creating an infinite size segment withlibmatroska

Steve Lhomme — 2012-05-17T07:39:02

It's hard to tell without looking at the code, but normally setting
SetSizeInfinite(true) on the elements you want to make infinite (you
have to do it on upper level elements as well, otherwise it doesn't
make much sense) should suffice.

On Tue, May 15, 2012 at 7:39 AM, Markus Goetz <markus< at >woboq.com> wrote:

Haali Media Splitter: Track limitation & playbackissues

Ben Humpert — 2012-05-16T00:15:35

Hi everybody.

First i want to thank you guys for such great work (matroska, haali's
splitter, coreavc)!

I have some issues with haali's media splitter. The first is that
there is a limit of 32 tracks HMS handles. I have here a self-created
mkv file with one video track (H.264), five audio tracks (AC3) and 29
subtitles (VobSub). Everything is shown in Halli's Splitter / VSFilter
except the last three subtitles. If i remove two audio tracks from the
mkv (or create a new one) only the last subtitle isn't shown.

If i play the mkv in MPC (with internal mkv splitter) i can see all
video, audio and subtitle tracks.


The second issue i have is very confusing. The first mkv i created
(H.264 video + AC3 audio + VobSubs) worked like a charm in every
player (including WMP 12 :) and i continued creating mkvs the same
way. Then suddenly the newest file stopped working. Normally i use WMP
12 64-Bit + Haali Media Splitter 64-Bit + CoreAVC 64-Bit but with that
combination the file didn't worked so i tried the same config

Re: Problem creating an infinite size segment with libmatroska

Markus Goetz — 2012-05-15T05:39:16

It was the latest ones, libebml 1.2.2 and libmatroska 1.3.0

On 08.05.12 16:20, Steve Lhomme wrote:

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Re: practical limit on number of frames in a lace?

Steve Lhomme — 2012-05-12T06:53:46

Indeed if TrueHD has 1ms packets you may add more than 8 frames at
once in a lace.

I'd say the optimum duration of a lace would be between 1/2 of the
video frame duration and the whole frame duration, so there's always
enough audio packets the video but not too much so the video frame can
come at the right time. Of course that would be in a buffer limited
player (and no B frames) when you can hardly buffer anything.

On Thu, May 10, 2012 at 10:13 AM, Moritz Bunkus <moritz< at >bunkus.org> wrote:

Re: practical limit on number of frames in a lace?

Moritz Bunkus — 2012-05-10T08:13:59

Hey,

I honestly don't know where the practical limits are. libmatroska
(which is used by mkvmerge) limits the number to 8 which is rather on
the low side.

However, one thing to consider is that most players use the audio
track as the source for A/V synchronisation. Now laces usually have
long packet durations, and they get longer the more frames there are
in a lace (obviously). If a whole packet is ~ 1s long then A/V sync
can become quite bad -- if the player doesn't know how to handle such
situations.

This can be remedied on the player's side by taking the default
duration into account: frame_timecode = packet_timecode +
frame_number_in_lace * default_duration. However, that only works for
audio formats with a fixed  number of samples per packet (e.g. MP3,
AAC, AC3) but not with ones with varying number of samples per packet
(Vorbis) as those don't have a default duration (or the calculation
would be wrong).

So basically I'd say... don't try to make packet durations go over
200ms or something like that,

Re: practical limit on number of frames in a lace?

Pavel Koshevoy — 2012-05-09T20:40:44

Actually, what really happened is that I stuffed more than 256 frames 
into a lace and overflowed the number of frames counter multiple times.  
So, the problem is in my code.  Sorry to trouble you.

However, I am still interested in hearing the practical limit on the 
number of frames in a lace.

Thank you,
     Pavel.

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practical limit on number of frames in a lace?

Pavel Koshevoy — 2012-05-09T19:36:36

Hi,

In my matroska muxer I try to cram as many audio frames into the lace as 
I can before the next video frame comes along, then I start a new 
SimpleBlock (and new lace obviously).  However, when processing an audio 
only compression there are no video frames available to limit the audio 
lace from growing too large.  That is how I've made a 30 second MKA file 
with Vorbis audio, where 250 frames are stuffed into a single 
SimpleBlock in a lace.

Media Player Classic can't play this file.  Neither can ffmpeg.  mkclean 
(v0.8.6) segfaulted when I tried using it to remux the file.

The absolute limit on the number of frames in a lace is 256.  What is 
the practical limit?  Also, does anyone care to see this 360Kb file I've 
made?

Thank you,
     Pavel.

PS. As a workaround I've modified my muxer to limit the number of frames 
in a lace to 8.

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Re: Technical question about integrating matroska

Steve Lhomme — 2012-05-08T14:26:02

If you use Segment Linking Haali's Splitter or VLC should be able to
see it as one single stream.

On Sat, Mar 17, 2012 at 10:29 AM, Fedor Inochkin
<fedor.inochkin< at >gmail.com> wrote:

Re: mkv and 7.1 pcm

Steve Lhomme — 2012-05-08T14:22:47

Theoretically yes, that may be a problem in mkvmerge. Also for such
files the channel mapping may be undefined...

On Sun, Mar 25, 2012 at 6:41 PM, Dima R <dimar102< at >gmail.com> wrote:

Re: libmatroska or libmatroska2?

Steve Lhomme — 2012-05-08T14:21:21

They both work, also libmatroska2 is not finished and comes with even
less documentation...

On Thu, Mar 29, 2012 at 9:07 AM, 周彬 <zhakalamu< at >163.com> wrote:

Re: Problem creating an infinite size segment withlibmatroska

Steve Lhomme — 2012-05-08T14:20:16

What code base/library are you using ?

On Sat, Mar 31, 2012 at 12:19 PM, Markus Goetz <markus< at >woboq.com> wrote:

Re: H264 Codec Private Data in header

Moritz Bunkus — 2012-04-26T09:00:54

Hey,

On Thu, Apr 26, 2012 at 10:19, Wilson Ko <W.K.H.Ko< at >student.tudelft.nl> wrote:


It's the same format also used in MP4 files: a six-byte header
followed by all SPS NALUs followed by all PPS NALUs. The header is
roughly this:

  buffer[0] = 1;
  buffer[1] = sps.profile_idc;
  buffer[2] = sps.profile_compat;
  buffer[3] = sps.level_idc;
  buffer[4] = 0xfc | (m_nalu_size_length - 1);
  buffer[5] = 0xe0 | m_sps_list.size();

What do you mean by "packet size"? The length of the size field for
each packet? If so that is stored in the fifth byte as mentioned
above.

Kind regards,
mo
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H264 Codec Private Data in header

Wilson Ko — 2012-04-26T08:19:18

Hi,

I am from the Technical University of Delft. Currently I am working on a project which requires me to understand the MKV header of a H264 encoded file. In particular, I would like to know how this is encoded in the header file and where the packet size of the codec is specified, could you give me more information about this? It is really important for my project, so I hope to hear from you soon.

Regards,
Wilson Ko
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Haali splitter feature request (forced subtitles)

Robert Šusta — 2012-04-24T09:12:19

Hi.
I would like to have the forced tag on the subtitles stream accounted
when selecting the default audio/subtitle pins on initial graph
construction. The haali splitter has in its options/languages very
usefull audio and subtitle languages field. I use this string by default
'slo,off;cze,off;*,slo;*,cze;*,eng;*,off' to have Slovak or Czech audio
with no subtitles if possible, otherwise the default audio with subs i
can read and understand and no subs if there are no readable subs in the
container.
I was hoping for something like this:
'slo,SLO;cze,CZE;eng,ENG;slo,off;cze,off;*,slo;*,cze;*,eng;*,off' where
an uppercased entry means subtitle track with forced flag. It will allow
me to have appropriate forced track enabled by default when present. For
some movies (like the Stargate movie where some dialogues are spoken
with Goa'uld language or many other movies with occasional multilanguage
dialogues and where forced subs are available, but now you have to know
this and enable the subtitle stream after player

problem with Matroska Muxer Directshow filter

Almendrote Muñoz, Francisco Javier — 2012-04-23T11:36:12

Hi,

We are developing an application that allow us to save a video stream in mkv files. In order to do this, we are using the Matroska Muxer directshow filter. We are crafting a mkv file every minute, and normally it works fine, but sometimes we got an exception that hangs out our application. We cannot hand it and we notice it because we get the following .Net 2.0 Framework error in the eventviewer:

Faulting application indrarecorder.exe, version 2.0.4.0, stamp 4d5d5cce, faulting module matroskamuxer.ax, version 1.0.0.9, stamp 4120b973, debug? 0, fault address 0x00008599.

Do you know what could can cause this?

Thanks in advance.

Best regards,

Javier Almendrote


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Problem creating an infinite size segment withlibmatroska

Markus Goetz — 2012-03-31T10:19:59

Hello,

My goal is to write a small application that creates a straming MKV.

However I am having problems creating an infinite size KaxSegment.
I played around with WriteHead, SegmentSize, SetSizeInfinite etc..

I'm expecting to get 18 53 80 67 ff in my stream, but I only get 18 53 
80 67 80 (or a variation of that for different values for SizeLength, 
but always size 0 instead of all bits set).

Can someone post a small snippet that does what I want to achieve?

thanks a lot,
Markus
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Re: question about not linear track timeline

Moritz Bunkus — 2012-03-30T05:40:12

Hey,

this is perfectly normal for video tracks which use B frames. Their
timecodes are in "presentation order" while they're stored in the file
in "decoding order": the decoder decodes them in the same order
they're located in the file, but the decoder will then re-order them
according to certain criteria that are unique to each codec type
before actually displaying the decoded picture.

For h.264 the rules how to order the timecodes for output into a
Matroska file (or MP4 file for that matter -- they do the same thing
we do) are pretty complex. If you want to get an idea how mkvmerge
does it here's the code:
https://github.com/mbunkus/mkvtoolnix/blob/master/src/common/mpeg4_p10.cpp
function "cleanup". It buffers all frames between two key
frames/recovery points, sorts them by their criteria (see the h.264
standard documents as well), assigns timecodes (either retrieved from
a source container or calculated from the timing information if the
source doesn't provide enough timecodes), and sorts them back in
d

Re: question about not linear track timeline

Pavel Koshevoy — 2012-03-30T05:11:58


The frames are stored in decode order according to DTS timestamp, but 
DTS timestamps are not stored in matroska.  The timestamps you are 
highlighting are presentation timestamps (PTS).  Frames are not 
necessarily decoded and presented in the same order.

Please read this explanation about various frame types, in particular 
B-frames -- http://forum.doom9.org/showthread.php?t=19436

     Pavel.
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question about not linear track timeline

alexander — 2012-03-29T21:10:00

Dear Friends,

Please help me to understand one strange thing...

Some video files has not linear timeline, please look at attached pictures.

The files are playing fine, but If i repack such files they are playing not correctly.

If i recalculate time for problem frames and and make time linear, the movie decoding correct, but playing not smooth, with short delays.

The question is...     is it was an error in packing software, or all is correct and such not linear time is because of codec specifics?

Sincerely yours,
Alex._______________________________________________
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libmatroska or libmatroska2?

周彬 — 2012-03-29T07:07:16

Hello,
We plan to use matroska in our project, but we hava a question.
As steve Lhomme said in http://lists.matroska.org/pipermail/matroska-devel/2010-October/003816.html

"libmatroska is not developped anymore." 
Can you confirm about it? If yes, we may use libmatroska2 instead of libmatroska. 

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mkv and 7.1 pcm

Dima R — 2012-03-25T16:41:41

Hi,

Does MKV support 7.1 uncompressed PCM audio? My project works great when
used with M2TS container created using tsMuxerGUI using .264 and .w64
files. When I add my files to mkvmerge GUI 5.4.0 for example, it recognizes
the .w64 (wave64 7.1ch 24-bit 48kHz) as MPEG4 part 10 ES. When I tried
using MakeMKV to create an MKV from the same blu-ray project, the file
wouldn't play.
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