Poor Quality of AVI -> VCD

[Quin]

I have a 45min AVI that I am trying to put onto a CD-R to play in my home DVD player. I used TMPGenc to convert it to a VCD format and then used Nero to burn it onto a CD.

I played around with the bitrate settings and that VBR/CBR selection in TMPGenc trying to improve the quality. I was finally able to get the software to output an MPG file that I could live with. In Windows Media Player, the video quality was somewhat reduced, but within acceptable levels.

However, when I put the burned CD into the DVD player, the video quality is borderline watchable. Its almost like it is out of focus. And, the faster the action, the worse the quality.

Any idea what I might be doing wrong? Or, would it be a fair characterization to say that VCD has a sub-VHS quality and I should not expect any better? Any ideas or suggestions would be greatly appreciated!

[junkmalle]

There is only one valid video bitrate for VCD, 1150 kbps CBR. Anything you make that doesn't conform to that will be non-standard. You're DVD/VCD player may or may not play it properly. The audio is fixed for VCD too: 44100 Hz, 224 kbit/sec MPEG-1 Layer2. Using anything other than that can also effect playback on VCD players.


Try using SVCD which allows for variable bitrate MPEG 2. Although the frame size is twice as large you can usually fit a ~45 min video on one CD in SVCD with Ok quality.

[Quin]

Thanks for the reply!

There is only one valid video bitrate for VCD, 1150 kbps CBR. Anything you make that doesn't conform to that will be non-standard. You're DVD/VCD player may or may not play it properly.

Interesting thought. I did this a couple of days ago and I don't recall what the final settings were that I used to burn. I will have to give it another go to see what results I get using those settings. I have found this newbie guide helpful in deciphering how this works.

The audio is fixed for VCD too: 44100 Hz, 224 kbit/sec MPEG-1 Layer2. Using anything other than that can also effect playback on VCD players.

Other than extracting the audio into a seperate WAV file for TMPGenc to recognize it, I did not fiddle with any of the audio settings.

Try using SVCD which allows for variable bitrate MPEG 2. Although the frame size is twice as large you can usually fit a ~45 min video on one CD in SVCD with Ok quality.

I tried SVCD and got even worse results. I am using the free version of TMPGenc which only includes a 30 day trial of MPEG-2 encoding. Either the trial doesn't work properly or I have codec issues or something. I've tried various bitrates and resolutions, but the left half of the screen doesn't get encoded correctly.

[junkmalle]

If you use TMPEGEnc's Project Wizard for VCD or Super VideoCD (VBR standard format) it will adjust all the settings and do whatever conversions are necessary. The only things you may have to adjust manually is the aspect ratio and maybe the minimum bitrate (some SVCD players don't like very low minimum bitrates).

If your AVI is from a DV camcorder with shakey, low light (grainy) footage you won't get results as good as from a DVD source.

A lot of DVD players don't support SVCD, and some don't support VCD, even when the CDs are completely within spec. Check the list of players here to see if others have had problems.

[Cole]

Quin, I am wondering that when you burned the original VCD using Nero, if it wasn't standard VCD settings then Nero may have re-encoded it to standard. There may be an issue there as Nero is reputed to be a poor encoder.

[mats.hogberg]

if it wasn't standard VCD settings then Nero may have re-encoded it to standard

That's my guess too. Nero is infamous for spontaneously (and without telling) reencoding (and butchering) even perfectly fine source material. I suggest authoring with VCDEasy, which will warn you for out of specs sources, but leave it at that.

/Mats

[guns1inger]

The long delay before burning is usually a give away.

[Quin]

if it wasn't standard VCD settings then Nero may have re-encoded it to standard

Nero is infamous for spontaneously (and without telling) reencoding (and butchering) even perfectly fine source material. I suggest authoring with VCDEasy,

Thanks for the responses! I definitely didn't do anything special in Nero to burn the CD, and certainly received no errors or warnings.

I will give VCDEasy a shot. I had tried to install VCDEasy a couple of weeks ago and had some problem with the installation. Don't recall what the issue was, so I will have to go back and revisit the installation.

Thanks for all of your help!

[Quin]

Well, I've now tried a couple of different things ...

(1) I've taken my original .mpg VCD that I created in TMPGEnc the other day and burned it using VCDEasy rather than Nero. I can see no appreciable difference in the quality between the two. One thing I did notice right away was the option between VCD 1.1 and VCD 2.0 in VCDEasy. I chose VCD 2.0, assuming this would be of a better quality. I do not recall that option in Nero; does anyone know which one Nero uses? Regardless, from my perspective, the VCD format is still a sub-VHS quality picture. Am I expecting too much from VCD or is this just the way it is?

(2) I've played around with the TMPGEnc settings for SVCD. By choosing NTSC Film, rather than NTSC, my problems with the left half of the picture have for the most part gone away. I chose NTSC originally because this is a recording of a TV cartoon rather than a film. If I correctly understand, the difference between these two sources is the framerate. My original .AVI is a DIVX at 29.97fps. My understanding is that VCD and SVCD are also 29.97fps. So, why do I get a better SVCD picture if the framerate isn't changing? My assumption is that it has something to do with the "Inverse Telecine" filter that gets used. The filter says that it is converting to 24fps; however, my input and output are both 29.97fps. So, is it converting to 24 and then back again? I am finding this issue rather confusing to say the least.

(3) The default (or is it standard?) SVCD resolution appears to be 480x480 pixels. My source .AVI has a 512x384 resolution. When I used the default resolution, the result (when played in Windows Media Player) is everything is all stretched out and everybody is really, really tall. If I change this resolution (after loading the unlock template), the picture looks better/normal. However, AVICodec then reports that the resulting .MPG is a 16:9 aspect ratio. I've tried both 512x384 and 480x384, with the same results. I've also fiddled with the Video Arrange Method and gotten the same results for "Full Screen" and "Full Screen (Keep Aspect Ratio)" As I don't have a widescreen TV, I have not yet tried burning this one. Should I even be concerned with what AVICodec is reporting on my output file? I realize that DVD players are different, but should I even be concerned with the resolution for the .MPG file?

(4) Lastly, how do you know if the source is interlaced or non-interlaced? I've tried both and not noticed any difference in the result. Does it really matter what you specify here?

Thank you for taking the time to read what has turned out to be a rather lengthy post. I really appreciate any assistance that you have to offer!

[mats.hogberg]

1) The quality is 100% governed by the encoding process, not how it's authored. Sub (or close to) VHS quality is what can be expected from VCD, yes. Best results with "perfect" source material like DVD. AVIs have mostly already been compressed once, and the best is already taken out of it.
3) 480*480 is the SVCD resolution. Period. Alternative could be 352*480 (CVD). It can be displayed 4:3 or 16:9. WMP seldom gets anything right.
When encoding, you should set source aspect ratio to 1:1, and video arrange to "full screen, keep aspect ratio"

/Mats

[junkmalle]

A 512x384 AVI file is probably not interlaced. The best way to tell is to open the file in VirtualDub and step through frames where there is some motion. If you see interlace comb lines it's interlaced. Also, if the frame rate is 23.976 it should be progressive. Don't rely on any software to tell you if it's interlaced -- software often gets it wrong. And be careful using media players, they often deinterlace on-the-fly so you can't tell for sure.

While your looking at the file with VirtualDub, use File -> File Information to check the frame rate. You can also use programs like GSpot and AVICodec.

Assuming your source is 512x384, 4:3 picture aspect ratio (1:1 pixel aspect ratio), progressive 23.976 fps you should do the following in TMPGEnc:

1) Select the Super VideoCD option from the Project Wizard. Use the 2-pass VBR Standard Format template.

2) Select the source AVI file. The Expert Setting For Source should be set to Non Interlace, 1:1 VGA, Film Movie.

3) Before encoding, go to the Settings dialog. On the Advanced tab make sure the Video Source Type is Non-interlaed (progressive). Source Aspect Ratio is 1:1 (VGA), and VIdeo Arrange Method is Full Screen.

4) On the same dialog, under the Video tab make sure the Encode Mode is 3:2 pulldonw when playback.

After encoding you will have a 480x480 MPEG 2 file. Depending on what you use to play this on your computer it may or may not display with the proper 4:3 picture aspect ratio (it may display a square picture). A set-top SVCD player should desplay it properly, stretched out to fill the full 4:3 picture aspect ratio.

[Quin]

Sub (or close to) VHS quality is what can be expected from VCD.

It looks like I am going to give up on VCD because of the poor quality.

480*480 is the SVCD resolution. Period. WMP seldom gets anything right.

I figured this one out the hard way. I tried burning my 480x384 SVCD. No picture when I tried playing on my home DVD player (sounded good, though). I then re-encoded it at 480x480. Even though it looks funny in WMP, it is watchable on the DVD player.

I'm still not real happy with the quality, though. While the SVCD is certainly watchable, it can get a little rough around the edges, especially during fast motion. If my terminology is correct, I think it is called "macroblocking". I don't know, maybe I am just being too picky.

Assuming your source is 512x384, 4:3 picture aspect ratio (1:1 pixel aspect ratio), progressive 23.976 fps

My source is a DivX .AVI at 512x384, 4:3 aspect ratio, progressive(?) 29.970fps, with a 911 bitrate. This is as reported by AVICodec.

To convert it, I used the SVCD/NTSC-Film template in TMPGEnc. I set my source to non-interlace, 4:3 display, film movie. The video arrange method was "Full Screen (Keep Aspect Ratio)". I used a VBR 2-Pass bitrate of Avg: 1907 Max:2520 Min:1150. I had to lower the average to 1907 to fit it on a single 74 minute CD. I also changed the motion search precision to "Highest Quality (very slow)". The encode mode defaulted to 3:2 pulldown when playback.

The inverse telecine filter is also required to make this work. Which makes absolutely no sense to me. If the source .AVI is 29.97 and the resulting .MPG is 29.97, then why do I need a filter to convert it to 24fps? But, if it isn't run through this filter, then the left side of the video is toast.

[TaoTeWingChun]

Welcome to the world of encoding, Quin. The one thing you will learn quickly around here is that if you start with an inferior source to begin with, you shouldn't get your hopes up too high for good quality results. The old 'Garbage In, Garbage Out' motto is never more panfully apparent than in video editing/authoring.

Good luck with your project, I see tons of valuable advice have been offered!

Cheers!

[DarrellS]

I would suggest buying a cheap DivX DVD player and just leave the file as a DivX file. Not really sure why everyone is still wasting their time with low quality VCD.

I can either play my AVIs from a CD-R or from a Data DVD using my Philips DVP642.

[Quin]

The one thing you will learn quickly around here is that if you start with an inferior source to begin with, you shouldn't get your hopes up too high for good quality results. The old 'Garbage In, Garbage Out' motto is never more panfully apparent than in video editing/authoring.

You are 100% correct about the GIGO principle! But, the AVI that I have looks pretty darn good in Windows Media Player; a lot better than anything I have created using TMPGenc. Are you saying that DivX AVI's, by there very nature, will never produce a quality result, no matter the tool or the process? Or do I just need to find a better AVI with which to experiment?

I would suggest buying a cheap DivX DVD player and just leave the file as a DivX file.

This is certainly a very good suggestion. Unfortunately, this isn't an option for me. You could not have known this, because I have never clearly stated my intentions with this little project.

My goal isn't to get this particular file to play on my home DVD player. But rather, my goal is to learn and understand the process of encoding and authoring before I go spend the money on the new hardware that I will need. Eventually, I will be purchasing a capture card and be working with those streams. The only reason this is a DivX file is that, up until a week ago, I was under the mistaken impression that DivX and AVI were synonymous.

Thanks!

[DarrellS]

This is certainly a very good suggestion. Unfortunately, this isn't an option for me.

I don't know. I think anyone that has a PC ought to have a DivX player.

My goal isn't to get this particular file to play on my home DVD player. But rather, my goal is to learn and understand the process of encoding and authoring before I go spend the money on the new hardware that I will need. Eventually, I will be purchasing a capture card and be working with those streams. The only reason this is a DivX file is that, up until a week ago, I was under the mistaken impression that DivX and AVI were synonymous.

If you are interested in capturing and editing video, I would suggest going ahead and jumping in and doing it. A good capture card doesn't cost a whole lot and the best way to figure it out is by doing it yourself. I mean, you can get ideas from people but until you do it yourself, you'll never really know for sure.

As for the AVI thing, a lossless compression is what you want to capture at to get the best capture without filling up an 800GB HD. As to what you decide to do with the file after that is up to you.

AVI is audio video interleave. DivX, XviD, Indeo, I263 etc... are different types of compressions used in encoding these AVI.
XviD is the best compression for good quality small file size AVI but you can use whatever compression you want as long as you have the codecs installed.

[junkmalle]

My source is a DivX .AVI at 512x384, 4:3 aspect ratio, progressive(?) 29.970fps, with a 911 bitrate... To convert it, I used the SVCD/NTSC-Film template in TMPGEnc. I set my source to non-interlace, 4:3 display, film movie... The encode mode defaulted to 3:2 pulldown when playback... The inverse telecine filter is also required to make this work. Which makes absolutely no sense to me.

You shouldn't have to convert from 29.97 to 23.976 fps. Use Video Movie rather than Film Movie. No 3:2 pulldown, no IVTC.

VCD and SVCD are prone to macroblocks during high motion sequences. They just don't have enough bitrate. They formats were designed to get ~60 and ~30 minutes of video on a standard CD, not for quality. You can get decent Divx/Xvid to MPEG2 conversions if you use enough bitrate and your source is decent.

Did you verify if your source was interlaced or deinterlaced? Interlaced video has things that look like this (extracted with VirtualDub):



On the left is a crop of picture at normal size, on the right a 4x enlargement of the golfer's head.

[Quin]

Did you verify if your source was interlaced or deinterlaced?

I looked at the AVI in VirtualDub, as you suggested. I did not see any comb lines. It also reports the framerate at 29.97fps.

You shouldn't have to convert from 29.97 to 23.976 fps. Use Video Movie rather than Film Movie. No 3:2 pulldown, no IVTC.

I am assuming that IVTC is inverse telecine. If I do not set this to Film Movie and use inverse telecine, it flat does not encode properly. The left side of the picture is garbage. As for the encode mode, I have never changed this from the default setting.

The inverse telecine filter is also required to make this work. Which makes absolutely no sense to me. If the source .AVI is 29.97 and the resulting .MPG is 29.97, then why do I need a filter to convert it to 24fps? But, if it isn't run through this filter, then the left side of the video is toast.

Frankly, this still baffles me.

VCD and SVCD are prone to macroblocks during high motion sequences. They just don't have enough bitrate. You can get ... conversions if you use enough bitrate and your source is decent.

I've given up on VCD as a viable format. As for SVCD, what kind of bitrate are you talking about? The default bitrate is 2520. I had to lower the bitrate down to 1907 to fit the 45 minutes onto a 74 minute CD. I guess the next thing that I can do is to use the source range filter to chop this thing in half so that I can up the bitrate. How high of a bitrate would you suggest? I am seeing quite a few macroblocks in high-motion sequences, with sporadic macroblocking during low-motion sequences.

BTW, I really do appreciate your time and patience trying to help me out with this. Thanks!

[junkmalle]

VCD and SVCD are prone to macroblocks during high motion sequences. They just don't have enough bitrate. You can get ... conversions if you use enough bitrate and your source is decent.

I've given up on VCD as a viable format. As for SVCD, what kind of bitrate are you talking about? The default bitrate is 2520. I had to lower the bitrate down to 1907 to fit the 45 minutes onto a 74 minute CD. I guess the next thing that I can do is to use the source range filter to chop this thing in half so that I can up the bitrate. How high of a bitrate would you suggest? I am seeing quite a few macroblocks in high-motion sequences, with sporadic macroblocking during low-motion sequences.

Sorry, 2520 kbps is the max for SVCD compatibility. I simply meant that you could get better MPEG2 results with a higher bitrate. For example you could go with 352x480 and much higher bitrates and still be compatible with the DVD spec (as Mats suggested earlier).

Another thing you might try: in an earlier message you indicated that you used an average of 1907, a max of 2520 and a min of 1150. Try reducing the minimum. The idea behind 2-pass VBR is to use less bitrate when it's not needed, and more where it is. By lowering the minimum you free up more bits for the scenes that require it.

(Paradoxically, some SVCD players will have problems with really low bitrates. The problem shows up in scenes that are mostly still, with just a tiny bit moving -- the little that's moving may show errors. I don't know exactly how low you have to go to get the problem -- but you can probably go as low as 500 or less.)

You can also encode one of your problematic scenes at 2520 kbps CBR. That will show you the best you'll ever see from SVCD. Then you'll know whether you want to persue SVCD or not.

Yes, IVTC is inverse telecine. I don't know why you can't go with a straight 29.97 fps SVCD encode. I don't have any problems with it. You could try frame serving from VirtualDub to TMPGEnc -- ie, use VirtualDub to decode the AVI and feed the decoded video into TMPGEnc. Thereby bypassing TMPGEnc decoding of the AVI, in case the problem stems from that. Or maybe you should just try another AVI file!

[Quin]

you indicated that you used an average of 1907, a max of 2520 and a min of 1150. Try reducing the minimum. ... you can probably go as low as 500 or less.

Lowering the minimum bitrate made a huge difference! There is still some macroblocking during high motion scenes, but you don't really notice it, per say, unless you are looking for it. Overall, much better picture!

You can also encode one of your problematic scenes at 2520 kbps CBR. That will show you the best you'll ever see from SVCD.

Excellent suggestion. I used the source range to convert a couple of minutes. Definetly a better picture.

Or maybe you should just try another AVI file!

Indeed I shall! I've found another DivX that has almost twice the bitrate as the one I've been playing with. We'll see how it looks after I'm done with it!

Once again, thanks for all of your help and guidance! I've actually learned a thing or two.