MKV Demuxing Problems

[Justin123]

Heya - Used the search function and read through a bit of the archives
I've got a simple problem that I'm not sure how to fix
Demuxed an AVC/MKV file and to my surprise the DAR is different to the original file, the framesize and resolution are still the same though.

According to Media Info the original file was:

Width : 704 pixels
Height : 480 pixels
Display aspect ratio : 16/9
Frame rate : 23.976 fps
Resolution : 24 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.231


And the demuxed file is:

Width : 704 pixels
Height : 480 pixels
Display aspect ratio : 1.467
Frame rate : 23.976 fps
Resolution : 24 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.243

Obviously something was lost or changed during the demuxing. Has the file been converted from anamorphic to square pixels or something?

Someone mentioned encoding the flagging back into the file, but I wouldn't have the slightest idea how to go about that in VirtualDubMod.
Would I just be better trying to convert the original file in VirtualDubMod? because I'm going to need to convert the file to something like MJPEG anyway.
Actually, I've forgotten how to even do that,

I do not want to encode it after I finish editing the footage, I need this to be consistant with my other assets.

Okay to summarise:
According to mediainfo DAR was changed from 16:4 to :1.467 - Usining VDM how can I set the flagging back to W/S 16:4
I need to reencode the file to MJPEG, but have forgotten the script for MKV serving into VDM (could I just put the AVC file into an AVI container so VDM could read it...or would I lose any information doing so?

Sorry if this post is incoherent, its late at night and I am exhausted.
I thank you for your time and help.

[poisondeathray]

Okay to summarise:
According to mediainfo DAR was changed from 16:4 to :1.467 - Usining VDM how can I set the flagging back to W/S 16:4
I need to reencode the file to MJPEG, but have forgotten the script for MKV serving into VDM (could I just put the AVC file into an AVI container so VDM could read it...or would I lose any information doing so?

Sorry if this post is incoherent, its late at night and I am exhausted.
I thank you for your time and help.

1) You might be able to use mpeg4modifier after the fact (if you are using xvid or divx to encode) , or use the AR encoding in XVID (doesn't work with all players)

Another option is to resize with square pixels , but then you need ~848x480 for 16/9 DAR , which would require more bitrate to encode because larger dimensions)


2) You can use

DirectShowSource("video.mkv")
or
FFMpegSource2("video.mkv", atrack=-1)

[Justin123]

I've noticed that after encoding a file that was served from an MKV (into VDM via Avisynth) the video doesn't come out right at all, square patches of the video flickers and flash about different scenes and colours. Though if I were to view the Avisynth file in MPC, before serving it into VDM I get the same problem.
Is that normal, or have I screwed up some things with the filters and decoders?

Resizing the video file to 848x480 sure fixed my DAR problems.
For the moment I've just resorted to demuxing both the video and audio, placing the video file into an AVI container, opening it in VDM and re-adding the audio stream and lastly, encoding the video to MJPEG. Doing it that way was also a ton faster than Re-encoding the original MKV file. Is there a more efficent way I can do things?

Again, your reply was really helpfull, thankyou.