Problems with interlaced/progressive on Simpsons DVDs

[zlep]

Ok, I have one last question (hopefully): How can I get correct the aspect ratio?
My source is PAL 4:3 so I added a custom line --sar 12:11 in MeGUI but MediaInfo says the aspect ratio is 5:4. I do not resize or anything, I just crop the little black borders which are on the original DVD (10 left, 6 right and 4 on the bottom and the top) so I get a file with 704x568.
Thanks again.

[jagabo]

MeGui must no be passing the --sar value to x264. I use the switch all the time with the x264 CLI encoder.

[zlep]

Hey jagabo, sorry, I don't understand what you mean. I tried the x264 CLI encoder but I guess I'm too inexperienced for this tool (guess it's just for the real experts, isn't it?).

[jagabo]

I tried the x264 CLI encoder but I guess I'm too inexperienced for this tool (guess it's just for the real experts, isn't it?).

No. It's pretty easy to use. I have several batch files like:

x264.exe --preset=slow --crf=18 --sar=8:9 --output %1.mkv %1

You need to provide the full path to x264.exe or put a copy of x264.exe in your \Windows\System folder.

I just drag/drop AVS scripts onto the batch file. I have some of the batch files in my SendTo folder so I can right click on an AVS script and select Send To ->x264_NTSC_16x8.bat, or whatever.

[zlep]

Ok, thanks. I will try this. But I guess I have to read some basic guides first.
Meanwhile, is there any chance to get the aspect ratio working correctly in MeGUI?

[jagabo]

Well, I just tried manually adding "--sar 12:11" to the custom command line options in MeGUI and the encoded .264 file showed the correct DAR in MediaInfo (720x576 video -> 4:3 DAR).

[zlep]

Hm, I don't get it.

This is the file I originally get. MediaInfo says it has an aspect ratio of 5:4 (and 1.239 on my Popcornhour):
http://files.videohelp.com/u/222746/ratio_5_4.mkv

I then changed the AR in MKVToolnix to 4:3. Played on my Popcornhour this gives me a bigger picture on my TV screen (and it says 1.3333). But it's the same size as the original file when I play it with the integrated media player of my Samsung TV:
http://files.videohelp.com/u/222746/ratio_4_3_mkvtoolnix.mkv

Both is 704x568 so I'm very confused right now.

[jagabo]

If you demux the video streams you'll find that MediaInfo reports both elementary streams as 4:3 DAR. I think what's happening is x264 has encoded the video streams with the specified SAR but MeGUI has flagged the wrong DAR (5:4) in the MKV header -- since it doesn't account for the x264 --sar flag. Some players will use the MKV header DAR, others will use the h.264 SAR.

[zlep]

Thank you for all your help. Very appreciated.
So that means it is basically correct encoded (4:3) but wrong flagged (5:4)?!
But which one is the correct one? The original DVD played on the PS3 has the same width as the 5:4 encoded file. But it actually looks a little bit too small. Does this mean the 4:3 one is correct? And if so, do I have to flag it with MKVToolnix or is there a way to flag it correctly with MeGUI?

Sorry, I guess my question is absolutely ridiculous but I'm really confused about this DAR and SAR

[jagabo]

So that means it is basically correct encoded (4:3) but wrong flagged (5:4)?!

Both are flags. One is in the h.264 data stream, the other in the MKV header.

But which one is the correct one? The original DVD played on the PS3 has the same width as the 5:4 encoded file. But it actually looks a little bit too small. Does this mean the 4:3 one is correct?

You're opening a big can of worms here.

The DVD spec refers to the MPEG 2 spec regarding aspect ratios. MPEG 2 only specifies the DAR (except in the case of 1:1 SAR, which isn't used for DVD). Of the three DARs suported by MPEG 2 only two are valid for DVD: 4:3 and 16:9 (2.21:1 is the other). The MPEG 2 spec clearly states that the entire frame contains the indicated DAR. Commercial DVDs nearly always use a full 720x576 (PAL) or 720x480 (NTSC) frame. This makes the SAR for 720x576 4:3 PAL DVD 12:11, 720x576 16:9 DVD 64:45.

Unfortunately, the ITU rec.601 spec for capturing standard defintition analog video defines the SAR differently. For 4:3 DAR PAL video the active picture is contained in a ~702x576 frame. Often a wider portion of the signal is captured, 720 pixels -- to be sure to get the entire picture in case it is broadcast slightly off center, or the capture is slightly off center. But that means the full 720 pixel wide frame is slightly wider than 4:3. In short, the SAR for 4:3 rec.601 PAL video is 128:117. Often, 12:11 is used as an approximation.

Here's a nice summary: http://forum.doom9.org/showthread.php?p=831046

The difference between these two specifications is usually ignored on DVD. DVDs made from analog tapes usually capture the tape with a 720x576 frame with rec.601 specs but encode as MPEG 2 as 4:3 DAR, ignoring the SAR difference. Digitized film DVDs might follow either spec.

Even DVD players are schizophrenic in this respect. Most upscaling players I've seen will scale the entire frame to the HDMI port. But they will output rec.601 at the analog ports.

In the end, to determine the correct DAR or SAR of any particular DVD you have to find something of known aspect ratio in the video, measure it, and do the math. Or you can arbitrarily choose to follow one of the conflicting specs. Unless you're measuring the picture on screen you won't usually notice the difference.

And if so, do I have to flag it with MKVToolnix or is there a way to flag it correctly with MeGUI?

I don't really use MeGUI so I'm not familiar with all its abilities. But as far as I've seen, there is no way to specify the DAR/SAR. By using the custom x264 flags you are bypassing MeGui's capabilities but the result is a file with conflicting AR flags.

[zlep]

Thank you very much for this explanation.

[theewizard]

"CLI" = command line interface

aka keyboard commands