Mpeg2 to .mkv unwanted Aspect Ratio Change

[Tom Saurus]

When my Hauppauge video capture card records I have it set at 720x480 and womble informs me the aspect ratio is 4:3. If I take this video and put it in Freemake Video Converter and use the 720x480 option for the .mkv file I end up with video that has a 3:2 aspect ratio. If I play the video in VLC, I can change the playback aspect ratio to 4:3 and it look like the original mpeg2 file. I still learning about .mkv files. I tried Handbrake, but it crops my video and screws it up, Freemake tends to want to do this as well, that is why I had to chose 720x480. Whether there are black bars at the top or bottom or not, my mpeg2 files are still 4:3, so I thought it best to carry that along into the .mkv file. Thanks in advance to anyone who can educate me on this matter.

[aedipuss]

dvd spec mpeg-2 doesn't use square pixels. mpeg-4 normally does. a 4:3 mpeg-2 should be encoded 4:3 like 640x480

[Tom Saurus]

aedipuss: Thank you for your response. I will give 640x480 a try and see what it looks like.

[jagabo]

Leave your video at 720x480 and specify 4:3 DAR or 10:11 PAR (called SAR in h.264) in your MKV file.

[aedipuss]

for hardware compatibility i always render 1:1 square pixel. for playing on a computer it doesn't matter as the software will honor the flags.

[jagabo]

I just make sure all the devices I buy respect aspect ratio flags. Every resize reduces quality.

[Tom Saurus]

jagabo: Thank you for this information. It looks like I will have to install Handbrake again and give it a try. Freemake Video Converter doesn't give me any options to selet 4:3 DAR or 10:11 SAR.

[davexnet]

You could always put it through mkvmerge after the file is created to set the DAR.

[aedipuss]

I just make sure all the devices I buy respect aspect ratio flags. Every resize reduces quality.

99.99% of what i convert is HD these days anyway so it just doesn't matter much.

[Tom Saurus]

I have installed Handbrake. Please instruct me on how to set the right settings so the .mkv file remains to the right dimensions. I assume you set these setting under the Picture tab. I have set the cropping by choosing Custom and putting 0 in all the boxes. The only way I select the box to keep the aspect ration is if I go to the Amaphoric tab and select Custom. I'm getting confused how to set this correctly in Handbrake. Once I get it figured out I will set a Preset. Thanks in advance for any help you can be in this matter.

[jagabo]

I would set handbrake to keep the original frame size (or just crop black borders) then:

https://forum.videohelp.com/threads/344902-Detelecine-decomb-issues?p=2151515&viewfull=1#post2151515

Use the same method of adding options to set the SAR to 10:11.

<edit>
I don't really use Handbrake. But it looks like the method of adding custom command line arguments won't work. Handbrake uses a colon to separate arguments. But the sar argument requires a colon between the x and y parameters (in x264 it's "--sar 10:11). Handbrake will get confused by that colon.

So you'll probably have to resize to a 4:3 frame size if you want to use Handbrake.
</edit>

[Tom Saurus]

jagabo: Thank you for taking the time to try to help me. Handbrake is a pretty complex program. Another thing I am finding I don't like is that when I check my encodes with that program it shows me the audio bitrate is variable. Audio bitrate should always be constant and I never intended it to be otherwise. I think I will go back to using Freemake Video Converter.

I find it disappointing that Freemake Video Converter even though they say on their website they want Feedback, they don't ever take the time to get back to a person when you offer suggestions that could improve the program; at least that has been my experience. This being said it is a great program.

[aedipuss]

vidcoder(gui for handbrake) may be a bit easier to learn than handbrake, and you can easily save your own presets.

[Tom Saurus]

aedipuss: I downloaded VidCoder and I get a security warning that the program doesn't have a valid security signature. Thanks for your advice, but I think I better not install the program when I am getting this warning.

[aedipuss]

that would be unique. it's clean.

[jagabo]

Free software doesn't come with security signatures since the author isn't going to pay for it. Not having one isn't anything to worry about. Just be sure you download from a reputable place and run an AV scan.

[Cornucopia]

And just guessing, but I'm pretty sure with a preset you can get handbrake to encode audio in cbr.

Scott

[Tom Saurus]

aedipuss: I downloaded Vidcoder the 64 bit version. I scanned it with Norton Anti-Virus and it has come up clean. The interface is simpler and I have been able to set a preset that the program remembers.

jagabo: The program says my mpeg2 files have a 8/9 aspect ratio. I fooled around a bit and it exports the same aspect ratio to the .mkv file. The resulting file when encoded and looked at in MediaInfo tells me it is 720x480 with a 4:3 aspect ratio. I am still disappointed that the audio is listed as variable, but I may be able to extract the audio at a constant rate in another program and patch that in as I believe that option is available.

Cornucopia: I hope I can discover a way to export the mp3 audio at a constant bit rate as that is ideal.

Thanks to you all for your advice. An interesting thing about VidCoder it is taking advantage of my quad core and using all four processor almost to full capacity.

[hello_hello]

Handbrake is a pretty complex program. Another thing I am finding I don't like is that when I check my encodes with that program it shows me the audio bitrate is variable. Audio bitrate should always be constant and I never intended it to be otherwise.

Who on earth told you that?
I've heard the argument for AVI.... it was never intended to hold VBR audio and doing so is a hack..... but while I don't personally think it's true, hack or not I've never once come across an AVI capable media player which didn't cope with VBR audio. It's fully supported and no doubt always will be and that's all that matters.

When it comes to newer container formats such as MKV or MP4.... well it's fairly obvious MP4s can contain VBR audio and the fact MP4 may include video as well doesn't change that in any way I know of, and it's certainly no problem with MKV.
I've never used Freemake Video Converter but most conversion programs I've used default to quality based encoding for AAC which is VBR.

If you use the anamorphic option in Handbrake it'll set the correct aspect ratio. without it, it'll convert the video to square pixels. Many encoding programs refer to setting the aspect ratio as some sort of "anamorphic" option. I'm not a Handbrake fan myself, I use MeGUI which is probably harder to learn, but Ripbot264 or ffcoder might be simpler alternatives. I've not used either myself in quite a while.

[hello_hello]

I tried Handbrake, but it crops my video and screws it up, Freemake tends to want to do this as well, that is why I had to chose 720x480. Whether there are black bars at the top or bottom or not, my mpeg2 files are still 4:3, so I thought it best to carry that along into the .mkv file. Thanks in advance to anyone who can educate me on this matter.

If you encode a 4:3 (or 16:9) display aspect ratio DVD or mpeg video, and you remove some of it while encoding, (or if the program crops the black bars automatically as some do) even if all you're removing is the black bars, the display aspect ratio must change. The 4:3 aspect ratio includes everything, active picture area, black bars and all. I don't know whether that's why you think the programs are screwing things up if they change the aspect ratio or not, but Freemake Video Converter might be doing the right thing until you manually select a resolution (I've never used it). Any decent encoder GUI will calculate the correct aspect ratio for you as you crop (or if it does the cropping automatically).
Likewise you could crop the black bars and resize the remaining video back to 720x480, but as you've resized it in order to do so the aspect ratio must change.

Of course if you don't crop anything, and encode it black bars and all, if you start with 4:3 you should end up with 4:3 (unless you convert to square pixels, 720x480 -> 640x480, for example). If that's what you're doing then I guess you can ignore this post.

[Tom Saurus]

hello_hello: Thank you for your input. My original mpeg2 files are from my Hauppauge Capture Card. They are 720x480 (4:3). I am just experimenting with .mkv video, I generally convert using Tmpgenc Xpress 4.0 using the home theater Divx profile. I burn the files to data disc and play them on my Phillips Ultra Divx player. I have abandoned making ultra divx discs because I find it far better to always be able access the original .divx files. My video captures are generally in stereo so I set VidCoder to encode to stereo .mp3 files. I think I will switch to ac3 stereo.

I am saving up for a LED TV to use as my computer monitor/television. I think I am going to buy a WD Player as well. I am learning more as I go along about .mkv files. I experimented yesterday with 1800 two pass bit rate and it did not look as good as videos I did at the same rate with Freemake Video Converter.

[hello_hello]

. I am learning more as I go along about .mkv files. I experimented yesterday with 1800 two pass bit rate and it did not look as good as videos I did at the same rate with Freemake Video Converter.

Which other program did you use which produced less satisfactory results? Both using the x264 encoder?
There could be lots of reasons for that, but in theory if you apply the same cropping/resizing/de-interlacing etc and use the same x264 encoder settings then you should get the same results. I've never used Freemake Video Converter and barely used Handbrake as I've never warmed to it (assuming it's the other program) so I couldn't guess "why".

Have you tried quality based x264 encoding? Most people do it that way these days. Officially I think it's called CRF (constant rate factor) encoding, but GUIs may refer to it as constant quality or something similar. The idea being you pick a quality rather than a bitrate or file size, and each encode should have pretty much the same quality relative to the original video (all other x264 settings being the same). Video can be harder or easier to compress for several reasons so for a given quality the bitrate and file size required can vary quite a lot.
Encoder GUI's generally seem to default to a CRF value of 20 which gives you a fairly high quality. Lower values increase the quality while increasing the bitrate/file size. Most people don't go below CRF 18 but some go down to around CRF 16, however the file sizes at that quality tend to be rather large.

When it comes to aspect ratios, the general idea is to encode without altering the "picture" aspect ratio (for want of a better description). Meaning the shape of objects in the video itself should remain unaltered. That'd really be the way to test whether a program is messing with the aspect ratio. If you open the original video using a media player, then open the encode using another instance of the same player and compare the two, the pictures should look identical. The display dimensions may be slightly different if the black bars were cropped (and probably should be as some of the video was removed), but ideally you won't see any "stretching" or distortion of the picture in the encoded version, even if it's no longer 4:3.
It's pretty easy to run two instances of MPC-HC to compare video.

[Tom Saurus]

hello_hello: I continued my experiments yesterday with VidCoder and got quite satisfactory results. I went back to mp3 sound as I found the ac3 sound was flawed by noise being introduced. The mp3 sound was flawless, exactly like the original. My encodes were at a 750kbs bit rate with 2 passes and on a 20 inch screen they looked fairly good. I am liking VidCoder quite a bit. The aspect ratio problem has been resolved the dimensions are 720x480 and the aspect ratio is (4:3). I liked that whatever I set the preset at the program saved that information and I used the batch encode feature yesterday and that worked out pretty good. Thanks for your additional input, as I have learned quite a bit from your responses and the responses of other videohelp members who have posted to this thread.

[Tom Saurus]

I found some instructions on the internet to go into the settings of VLC so that it can handle .mkv files better. There were quite a few instructions, but back before I performed this task, all the .mkv files no matter the bitrate were blocky and distorted at times when they played.

I noticed a setting in Handbrake and VidCoder in the Video Filters tab part of the programs and I didn't turn it on but I wonder what it means. It was referred to a deblocking. Please educate me about this feature. Thanks in advance for any information on this matter.

[hello_hello]

I noticed a setting in Handbrake and VidCoder in the Video Filters tab part of the programs and I didn't turn it on but I wonder what it means. It was referred to a deblocking. Please educate me about this feature. Thanks in advance for any information on this matter.

Encoders basically encode the video in "blocks". If you try to compress video too hard it becomes more and more noticeable. Usually you'll notice "blocking" in dark or low detail areas of the video first (where it's less important), but the more it's compressed the more it shows in high detail areas too. An extreme example would be something like this: http://www.rafanvids.com/quality/artifacts1.jpg

A debocking filter would attempt to "smooth out" those blocks, but like most filters they'll usually have adverse side effects too, such as smoothing out some of the detail you want to keep. It's probably not something you want to use unless you know you need to.

[Tom Saurus]

hello_hello: Thank you for this information.