Help re-encoding mkv to fix display aspect ratio

[bowiebowie]

Hello!

I want to re encode a mkv video to fix the display aspect ratio. basically the original encoder put the Width value in the Height and the other way around.

Using VidCoder I got a bigger file even without encoding the audio track.

My question is how to adjust the settings so it re encodes the video and obtain the same file but with the correct aspect ratio.

Here is the MediaInfo:

Video
ID : 1
Format : MPEG Video
Format version : Version 2
Format profile : Main@Main
Format settings, BVOP : Yes
Format settings, Matrix : Custom
Format settings, GOP : M=3, N=12
Format settings, picture structure : Frame
Codec ID : V_MPEG2
Codec ID/Info : MPEG 1 or 2 Video
Duration : 2h 46mn
Bit rate mode : Variable
Bit rate : 2 959 Kbps
Maximum bit rate : 3 060 Kbps
Width : 352 pixels
Height : 576 pixels
Display aspect ratio : 4:3
Original display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 25.000 fps
Standard : PAL
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.584
Time code of first frame : 00:00:00:00
Time code source : Group of pictures header
GOP, Open/Closed : Closed
Stream size : 3.44 GiB (90%)
Default : Yes
Forced : No


Thanks in advance.

aa

[jagabo]

352x576 (352 wide, 576 tall) is half D1 resolution and is very common. It's also flagged as 4:3 display aspect ratio. So it's probably not a mistake. Maybe your player just isn't displaying it properly.

[bowiebowie]

Yes, I did notice it was set to display 4:3. The problem is my TV, so I need to re-encode.

I ended up with a 4.6 GB file from a 3.8 GB.

[jagabo]

I ended up with a 4.6 GB file from a 3.8 GB.

Use a lower bitrate.

file size = bitrate * running time

[bowiebowie]

I wondered if there is a way to replicate the original video, just changing the AR. I will lower the bit rate.

[Bernix]

Sorry to disturb you, but what if you change original aspect ratio in your original file to 2:3 ? Cant it helps ?

Bernix

[bowiebowie]

no problem Bernix.

how do you suggest i change the aspect ratio?

[Bernix]

Hm, I thought it is posible in MKVtoolnix. But you can try set width height to 704 576. I know that only some players supports it. But you can at least try it. Sorry I thought it is easy to change original AR.

Bernix

[bowiebowie]

No, my TV does not recognize these changes. I need to re-encode.

[jagabo]

It's an MPG file and it's already flagged as 4:3 DAR. If you're TV doesn't support DAR flags you'll have to resize adn reencode the video. Change the resolution to 640x480 and flag 1:1 sample aspect ratio. I'm assuming here that 4:3 is the correct display aspect ratio.

[bowiebowie]

Yes 4:3 is correct. Thanks for the help. I will lower the bitrate

[jagabo]

Oh, wait. You said it's an MKV file. If so, try demuxing the MPEG 2 video (and whatever the audio is) with Mkvtoolnix. Then mux the video (and audio) into an MPG container. The TV may understand the DAR flags in the MPG container. The free version of Tmpgenc might work for the muxing. Or ImagoMpeg-Muxer. Or even ffmpeg if you can deal with command line programs.

I just checked, MkvExtractGUI will extract the MPEG 2 video in an MPG program stream container (the audio will be in a separate file). You can test that MPG file to see if your TV displays it correctly. If so, then you can mux the audio and video together.

[bowiebowie]

Will test. Tomorrow I will post the results. Thanks!

[bowiebowie]

Oh, wait. You said it's an MKV file. If so, try demuxing the MPEG 2 video (and whatever the audio is) with Mkvtoolnix. Then mux the video (and audio) into an MPG container. The TV may understand the DAR flags in the MPG container. The free version of Tmpgenc might work for the muxing. Or ImagoMpeg-Muxer. Or even ffmpeg if you can deal with command line programs.

I just checked, MkvExtractGUI will extract the MPEG 2 video in an MPG program stream container (the audio will be in a separate file). You can test that MPG file to see if your TV displays it correctly. If so, then you can mux the audio and video together.

No, my TV didn't display it correctly.

In VidCoder under High Profile/ Settings / Video / Quality, I chose Avg Bitrate and it automatically calculated it. Worked perfectly! Thanks for the help.