MKV to MPEG2 - Not dropping frames, but not smooth - think it's audio

[Shade00]

Ok, I have some 720p MKVs that I am trying to convert to MPEG2s. The reason is I am tired of trying to get hardware acceleration for h264 material on my Nvidia cards. My primary machine has a powerful enough CPU to play the MKVs without needing hardware acceleration, but my bedroom HTPC is a 1.2ghz Celeron 220 (Core 2 based) with 1gb DDR2 and a Geforce 6200. This machine will not play 720p MKVs smoothly. However, the same material in MPEG2 is hardware accelerated using Nvidia's Purevideo MPEG2 decoder, so the 1.2ghz system plays the files using the Geforce 6200 at 21-30% CPU usage, vs. the 100%+ of the MKVs.

So I've used HCenc to convert the MKV video to an MPEG2 elementary stream (.m2v), then I extract the audio using MKVextract. Finally, I mux it all back to MPG using ImagoMPEG muxer.

The problem is this: video looks fine visually, it plays back at 24~ fps, but every couple of seconds it'll sort of jump - I don't really know how to describe it. Playing back the .m2v in Media Player Classic results in smooth video playback. Once I mux the audio back in, though, it plays funky. The audio is AC3 six channel. I've tried using the Nvidia Audio Decoder, which distorts the audio, and results in the same playback. Ffdaudio decoder plays it fine, with the same behavior. AC3 decompressor exhibits the same behavior. I don't know what else to try. Any help will be greatly appreciated.

[guns1inger]

Use MediaInfo to confirm that the source was 23.976 fps, and not 25 fps

[Shade00]

Thanks for the useful program. I was looking for something like that.

Source is confirmed to be 23.976fps. The audio stream is 640kbps 6-channel AC3.

[guns1inger]

That is a stupidly high bitrate for 5.1 AC3. Most commercial discs are 384 or 448 kbps for AC3 5.1. Are you taking this into account in your bitrate calculations ?

Try this. Media Player Classic -> File -> Open File. Load your m2v in the Open field, and your AC3 audio in the Dub field. How does it play ?

Finally, you might try running the AC3 through AC3fix to see if it finds any problems with the audio stream.

[Shade00]

Interesting. I just muxed the file to .ts using tsmuxer and playback was great in MPC. Hardware acceleration was working with CPU usage between 3-8% (25-30% or more without HA), sound was in sync, and smooth playback. That seems to point me to Imago MPEG muxer as the culprit. Is there any other way to mux to MPG? I guess it wouldn't be a problem keeping the files in .ts format.

[Delta2]

Put in here the full information MediaInfo gives about your M2V converted video...

because I bet you made the same foolish mistake I did

quotes from a forum :

http://www.avi2iso.com/forum/avi2iso/mkv's-and-avi2iso/msg2628/#new

======
I completed my mkv conversion late last night (that CCE sure does work faster than anything else I have seen) and played the iso.

Big problem. The entire video stutters constantly and skipping frames.

I am running a pretty good system but do you think that this might have something to do with my graphics/sound card on the pc.

...

I know I'll have to try burning this to disc at some point to test it but this was by far the worst conversion I have seen. The VSO and DVDflick conversions played back perfectly apart from an approximate 0.5 sec audio sync issue. This latest conversion is completely unwatchable.

...
=========


it is very similar to your problem...and I made the same foolish mistake as you

after the fixing he replied :



========
Absolutely crystal clear picture, perfect sync and pretty damned good audio.

By far, and I do mean by FAR the best bit of conversion software I have found for this file type and I have done a lot of trials believe me.

The fact this is free, the support is second to none, and that it WORKS makes me send you a hearty thank you Delta.

Keep up the damned fine work my friend.
=======

[Delta2]

well...now..the foolish part : did you forgot to pulldown your M2V ? well, I forgot to do that, foolish mistake

http://avi2iso.planetaclix.pt/avi2iso.rar

http://fileforum.betanews.com/detail/AVI2ISO/1191447822/1

---------
second layer AIO M$ developer

[Shade00]

AVI2ISO does seem to work very well, but it only downconverts my files to DVD resolution. I want to retain their original resolution (i.e. 1280x528) for PC playback. I do not want to burn these to DVDs.

The .ts files I have created seem to be working great. However, I have a new problem: I have an .mkv file with a 16:9 pixel ratio (I think it's 960x528), but the horizontal resolution should have anamorphic pixels. However, in the conversion the MPEG2 headers apparently didn't get the memo. So they think that the resolution is still 16:9 instead of the appropriate aspect ratio. What program can I use to patch the headers and get the appropriate AR?

[guns1inger]

mkvextract (requires mkvtoolnix in the same folder) - demux the content. Then use mkvmerge to put the audio and video back into the mkv container with the correct settings. This usually works, although it depends just how screwed up the source is. I have seen some very weird mkv files.

[Shade00]

I tried your advice gunslinger, but unfortunately HCenc still sees the video as 960x528 instead of 1280x528. So I figure I have a couple of options:

1) find a program to change the .h264 file's information

2) find a program to change the MPEG headers (I have one called hdpatch, but it claims the .ts file has only 1 header)

3) is there a way to force a resolution or aspect ratio in my AVS script?

Thanks for your help guns1inger.

[Delta2]

Try FFMPEG instead of HCEnc, but I didn't tried

ffmpeg.exe -i VIDEO.MKV -vcodec mpeg2video -vtag MPG2 -b 5000 -minrate 200 -maxrate 9800 -dc 10 -aspect 16:9 -s 1280x528 -y video_teste.m2v

[Delta2]

I made only a single conversion with a sample of 1280x720, you must set the buffer size, which can be bigger

C:\AVI2ISO_DSV\dvdauthor\ffmpeg.exe -i eragon.mkv -vcodec mpeg2video -vtag MPG2 -b 5000 -minrate 200 -maxrate 9800 -r 23.976 -s 1280x720 -bufsize 20000 -dc 10 -aspect 16:9 -y video_teste.m2v

that will produce a huge Mpeg2 file at 1280x720

Muxman wont accept it, you must use MPLEX from DVDAuthorGui instead, or another muxer

lol...what a crazy conversion, I don't have a monitor for this, so huge, but if you want too...it is possible

but don't forget to pulldown 23.976 to 29.970 or change the rate directly in that command

whatever you stuck into......good luck

========
http://fileforum.betanews.com/detail/AVI2ISO/1191447822/1
AIO M$ Developer