Understanding MKV files

[carlmart]

I use my LG BD390 bluray player to stream mkv files from my computer to my plasma TV.

The problem is that lately most mkv files are refusing to play, and I need to remux them again in order to do so.

That seemed to work in the past, but that was not so usual. Now sometimes I need to re-convert the AC3 file before remuxing.

On one forum dealing with LG BD390 owners it was suggested that the header compression might be turned on, and the hardware could not deal with that.

Can someone explain to me what does that mean and why mkv files are not always the same, coding wise?

[davexnet]

Header compression, which apparently has always been in the spec was not used often uintil recently.
MKVtoolnix started using it by default, but it can be set to "off" permanently by modifying the preferences.

Hardware devices, and their firmware, were taken by surpirse and didn't support it.
Same devices in most cases are getting firmware updates....

[carlmart]

And where is that header information?

This is what Mediainfo shows me for one of my files

General
Complete name                    : H:\Download\file.mkv
Format                           : Matroska
File size                        : 887 MiB
Duration                         : 42mn 1s
Overall bit rate                 : 2 952 Kbps
Writing application              : x264.exe
Writing library                  : mkv2rls x264-tv version built on 2011. febr. 17

Video
ID                               : 1
Format                           : AVC
Format/Info                      : Advanced Video Codec
Format profile                   : High@L3.1
Format settings, CABAC           : Yes
Format settings, ReFrames        : 5 frames
Muxing mode                      : Container profile=Unknown@3.1
Codec ID                         : V_MPEG4/ISO/AVC
Duration                         : 41mn 58s
Bit rate                         : 2 509 Kbps
Width                            : 1 280 pixels
Height                           : 720 pixels
Display aspect ratio             : 16/9
Frame rate                       : 23.976 fps
Resolution                       : 24 bits
Colorimetry                      : 4:2:0
Scan type                        : Progressive
Bits/(Pixel*Frame)               : 0.114
Stream size                      : 753 MiB (85%)
Writing library                  : x264 core 115 r2008 4c552d8
Encoding settings                : cabac=1 / ref=5 / deblock=1:0:0 /  analyse=0x3:0x113 / me=umh / subme=8 / psy=1 / psy_rd=1.00:0.00 /  mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 /  deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=18 /  sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 /  constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=2 / b_bias=0 /  direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 /  keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf  / mbtree=1 / crf=19.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 /  ip_ratio=1.40 / aq=1:1.00

Audio
ID                               : 2
Format                           : AC-3
Format/Info                      : Audio Coding 3
Codec ID                         : A_AC3
Duration                         : 42mn 1s
Bit rate mode                    : Constant
Bit rate                         : 384 Kbps
Channel(s)                       : 6 channels
Channel positions                : Front: L C R, Surround: L R, LFE
Sampling rate                    : 48.0 KHz
Stream size                      : 115 MiB (13%)
Title                            : English
Language                         : English

[jagabo]

I don't know of any tools that shows whether or not "header removal compression" is used in an MKV file. In MMG select File -> Options. Enable the "disable header removal compression..." setting. Remux any files that aren't working. MMG remembers this setting so you only have to make the change once. I think you need to exit MMG and restart it for the change to take effect.

MKV, like any complex file format, has many options, some of which are not compatible with some devices. About a year ago the default in MMG changed from not using header removal compression to using it. I think it was stupid to enable it because it only makes a tiny difference in file size. Like 1/20 of a percent.

[carlmart]

My MKVmerge version is 3.1.0 and it doesn't show any "disable header removal compression..." option.

I never upgraded to newer versions because there were too many reports of merges made with newer versions not working in this player.

Though I never tried that myself. Maybe it's time I should.

[jagabo]

Yes, 3.1.0 was before header removal compression became the default.

[kukkamies]

Forget about mkvtoolnix. When you open your mkv file with mediainfo (free software) you will see "(Header stripping)" at the end of audio info if your file has that.

To fix it just download haali media splitter. Install it, and run gsdemux.exe from it's install directory. Open .mkv file in it, you see streams, disable the ones you dont want to destination output file (ie. foreign subtitles etc.), choose save path and hit start.

U will have .mkv file without header stripping after. Rarely (had it like 1/100) it still shows (header stripping) mention there but it's not really there (bug perhaps.. but so rare I didnt bother to investigate more).

Alternative way is to get bdtoavchd which has file -> mkv option, that also "fixes" the crap. Enjoy.

[jagabo]

When you open your mkv file with mediainfo (free software) you will see "(Header stripping)" at the end of audio info if your file has that.

Thanks. I never noticed that before. I verified it correctly indicates the use of Header Removal Compression.

[carlmart]

Well, the problem seems to be more complicated that I thought it might be.

After reading your directions, I went find a file that refused to play on my LG BD390. Then I went back to my computer, downloaded the latest version of Mediainfo, and opened that problematic file. There's no header stripping on the audio info.

I haven't tried anything yet with this file, but usually merging the file again solves it. Sometimes I need to extract the AC3 file and remerge it with the old file. Even then, sometimes the video plays fine but the audio plays in slow motion, and I have to process it with avisynth to get a new AC3 file. Then re-merge it. Usually does solve the problem. I don't know what the problem is on this file yet.

What should I do now to see what might the problem?

[jagabo]

It sounds like you have several problems. Each one may require a different fix. Concentrate on one at a time. TVs are not know to be very robust media players.

[carlmart]

This is not a TV, it's an LG bluray player that can also be used as a media center.

What are the problems so I can concentrate at one at the time?

I already mentioned two fixes, one involving just a re-merge and the other involving audio processing, and then a re-merge.

But I would like to know where the problem is to see if there are other ways out.

[kukkamies]

This is not a TV, it's an LG bluray player that can also be used as a media center.

What are the problems so I can concentrate at one at the time?

I already mentioned two fixes, one involving just a re-merge and the other involving audio processing, and then a re-merge.

But I would like to know where the problem is to see if there are other ways out.

Well, why dont you just do like I said on earlier post. Run the mkv through "gsdemux.exe" (haali splitter), or bdtoavchd (file mode -> mkv to mkv) and strip everything you dont need. Both of them "normalizes" the file so it probably plays fine after on your lg br player. Try it and tell if it works?

[carlmart]

OK. I'm trying bdtoavchd as I write this. For now the only thing I don't like it that it's very slow. Pass 2 will take about 1 hour to process a 1Gb mkv file. Don't know how long will take the next step.

The processing I did before took about 15 minutes, which is still a lot considering I would have several files per day to process.

The problem seems to be the hardware, as LG stopped updating the firmware for this model.

I'm already considering buying a dedicated media center, as they usually update firmwares more often, even if the model is not the last one released, which is not what LG does.

Edit: definitely not the program for this processing. Next step was to take more than 3 hours!

[aca28]

Newbie question here so don't gang up on me. I tried searching with no avail.
Trying to play a MKV file on my BD690 (specs should be simular to the BD390)
It recognizes the file but when trying to play it states "Resolution not supported"
The file is from my JVC Everio GZ-HM650bu HD Cam. So I am thinking my camera is either recording to high or too
low of resolution for the DVD player. Does anyone know what the Max Resolution for playback on the BD390/690?

Thank you

[jagabo]

Newbie question here so don't gang up on me. I tried searching with no avail.
Trying to play a MKV file on my BD690 (specs should be simular to the BD390)
It recognizes the file but when trying to play it states "Resolution not supported"

So, what's the resolution of your files?

[aca28]

My HD CAM is s et to "XP" for video quality and x.x.Color is turned "On"
Ther is only one more setting higher then "XP" and that is "UXP" (There are two lower settings as well)
In The specs it states that XP is 1,220,000 pixels with AIS on.
The Cam itself has and HDMI out so I would assume it would be at least 1080p out but that does not nessarily mean the file is 1080p?

[poisondeathray]

How did you get a mkv from your JVC? That is not the native recording format

You can use a program called mediainfo and identify resolution and characteristics of video files

[aca28]

I ran it through Medianfo. thanks. See below.

Video
ID : 4113 (0x1011)
Menu ID : 1 (0x1)
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.0
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Format settings, GOP : M=3, N=15
Codec ID : 27
Duration : 3mn 3s
Bit rate mode : Variable
Bit rate : 16.3 Mbps
Maximum bit rate : 17.0 Mbps
Width : 1920 pixels
Height : 1080 pixels
Display aspect ratio : 16:9
Frame rate : 29.970 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First
Bits/(Pixel*Frame) : 0.262
Stream size : 356 MiB (95%)

[aca28]

Sorry, I did not finish the answer to your question. BD690 does not recognized .MTS (Native from Cam)
I was reading another post on here that just changing the extension to MKV it would work. Which I did and my BD690 then recognozed the file. but I get the resolution error?

[jagabo]

Sorry, I did not finish the answer to your question. BD690 does not recognized .MTS (Native from Cam)
I was reading another post on here that just changing the extension to MKV it would work. Which I did and my BD690 then recognozed the file. but I get the resolution error?

Changing the extension is not the same as remuxing into an MKV container. I suggest you perform a proper remux into an MKV container. Otherwise, your video looks like normal 1080i.

[carlmart]

The LG player should play 1920x1080 files alright, but they should be legitimate mkv files.

mts files should be converted onto mkv, either by demuxing them, then muxing the files with Mkvmerge or by conversion.

[jagabo]

You can use TsMuxer to demux the MTS file to elementary streams.

[cal_tony]

For what its worth... MMG will allow you to add or remove parts of an existing MKV. You can remove DTS and replace it with AC3 for example.

However, many players balk at this. My WD player will take upwards of 20 sec. to play such a re-muxed MKV. My Seagate players will only play such a re-mux if it is shorter than 30 min.

I do not have any of these problems if I separate out the streams with one of the MKV de-muxing tools and individually insert them into MMG.

My software players don't seem to care but my hardware players are not so forgiving.

Tony

[carlmart]

I do not have such a problem with my mkv files, and I do that DTS fro AC3 replacements all the time, to make mkv files smaller so they can fit into SL or DL DVD disks. Never had a problem playing those files in my BD390.

[jagabo]

Maybe a "header removal compression" issue?

[carlmart]

The LGs seem to be tricky MKV players, and I thought those problems I described at the beginning that I had with my BD390 would be solved with the BD690 model, with newer firmwares.

Apparently that is not the case.

It's a pity because there are not that many separate MKV players and mkv is a great compression form. Don't you think?

[aca28]

Thanks for all the good info. and help. It would have been nice (and quick) to just transfer the Cam Files right to DVD player and play.
(without remuxing and all that first) I guess you still cant have your cake and eat it to? Thanks again.

[davexnet]

Has anybody called LG support to see what the situation is?

[carlmart]

Thanks for all the good info. and help. It would have been nice (and quick) to just transfer the Cam Files right to DVD player and play.
(without remuxing and all that first) I guess you still cant have your cake and eat it to? Thanks again.

But DVDs are SD, and your files are HD! Why would you do that?

[aca28]

I'm not actually wasting time on DVD's. I record Home movies via the JVC Cam (HD) and then put them on my BD690 Hard Drive. Thing is I have to down convert thenm to make them Play. (to save space I convert to MPEG-4 HD using Xillisoft). I'm just saying it would be nice if the BD690 could read the files straight from the JVC which puts them out in .mts. (BD690 wont even recognize .mts) but when I switch to mkv like someone here suggested on another feed the BD690 recognizes but states incorrect resolution?) I guess I'll have to wait for an update?? I am speaking with LG supprt (like that is really getting me somewhere.LOL) and will report anything new.