Lisa B.'s Guide to Standalone DVD Player Compatibility

If you are tired of burning an AVI to disc, only to find out that it doesn't play in your standalone DVD player, then this is the guide for you!

Although I wrote this guide with the Philips 642 in mind, I will talk about just about every AVI feature that could possibly affect standalone playback, so it should be useful for anyone with a standalone DVD player.

There are really only two tools that you need to diagnose your AVI's - MPEG4Modifier and GSpot. The latest versions of these can always be downloaded at the great general-purpose video site, www.videohelp.com, in the Tools section. Make sure to download the latest Beta of GSpot, since it contains many features not in the latest stable version. You may also want to download VirtualDubMod^? from the same site.

Diagnosing your AVI with MPEG4Modifier

After launching MPEG4Modifier, simply click the browse button, then select and open your AVI.

A. Aspect Ratio

This should be "Square Pixels". If it is anything other than "Square Pixels", the Philips 642 will not play it. For other players, you may want to make a small test sample, burn to CDRW, and see what happens.

To change the Aspect Ratio to "Square Pixels", just click the radio button for "Square Pixels", click the "Save..." button, and you will be prompted for a new AVI name....it will take a few minutes as it saves the new, modified, AVI.

Keep in mind that MPEG4Modifier is not an encoder. When you save out a new avi, it is just changing header and/or packaging information, so there will be no loss of video quality.

B. Packed Bitstream

The Philips 642 has no problem with packed bitstream, so if you have a Philips 642, don't touch this option. Some other standalones have problems with packed bitstream...the problem has been described as a "stuttering" of the video. Keep in mind, though, there are other possible causes of "stuttering", so you'll want to eliminate the other possible causes first.

You should not unpack the bitstream unless you need to. Packed bitstream can help maintain audio synch after editing or remuxing, for example.

To unpack the bitsteam, just click the radio button for "Unpack", click the "Save..." button, and you will be prompted for a new AVI name....it will take a few minutes as it saves the new, modified, AVI.

C. User Data

This is not very important, but it can tell you what version of DivX^? or XviD^? was used to encode the AVI. You may also tell if someone has mistakenly changed the 4CC code of the file.

D. Interlacing

The Philips 642 has no problem with a properly interlaced AVI. That being said, I have yet to come across a properly interlaced AVI in all my roaming around the internet. By "properly interlaced", I mean that the original material was truly interlaced (not just telecined), and that the interlace was properly maintained from source to final encoded AVI.

Here is what happens when you take a progressive source and encode it as interlaced:

1. In the Philips 642, if the frame rate is not 29.97, then there will be a very jerky playback. If the framerate is 29.97, then the interlace has no effect.

2. In other standalones, interlaced avi's may not play at all, or they may look fine. This you'll need to test using the provided support files.

MPEG4Modifer cannot "uninterlace" an avi. If you are dealing with a jerky playing interlaced AVI (and this is not due to wrong field order), then you will need to re-encode it.

The other thing that can go wrong with an interlaced AVI is that the field order can be wrong. If the field order is wrong, you will have a very odd jerky movement which I can't quite describe, so refer to the support files.

If you need to change the field order, just click the radio button that is not currently selected (either "Top First" or "Bottom First"), click the "Save..." button, and you will be prompted for a new AVI name....it will take a few minutes as it saves the new, modified, AVI.

E. Video Info

This button supplies some additional important info. Click it, and look for the following features:

1. QPel - The Philips 642 will not play Qpel. Some standalones will. You may want to make a small test sample and see what happens.

QPel cannot be removed from an AVI. If your player doesn't play QPel, then you will have to re-encode the AVI.

2. GMC - in parenthesis, you will see how many "warp points" were possible. GMC is associated with S-VOPs. At the bottom of the window, there will be a statistical breakdown of how many warp points were actually used in the S-VOPs. The important thing to note is the following: if it uses only 1 warp point 100% of the time, then the AVI will play without problems in the Philips 642. If, on the other hand, some S-VOPs use more than one warp point, then the AVI will quit playing as soon as it hits a "multi-warp-point" S-VOP.

GMC cannot be removed from an AVI, nor can the number of warp points be modified. If your player doesn't play GMC, then you will have to re- encode the AVI.

3. Quant type - The Philips 642 will play "H.263" or "MPEG" quantization type. The Philips 642 has problems playing "Custom MPEG" quantization type, but there is a workaround.

When the Philips 642 tries to play an AVI using "Custom MPEG" quantization, then you will typically see all these pixellated, blocky, psychedelic colorings. This can be fixed by pressing the "System Menu" button (on the remote control) twice.

The "System Menu" fix is a cheap fix, and you will still notice some funky color smearing throughout the film. This is mild enough that it is acceptable to many people. To get the best results, though, all AVI's with "Custom MPEG" should be re-encoded for proper playback on the Philips 642.

There is also a minor incompatibility between the Philips 642 and the "MPEG" quantization type, which is noticeable in certain kinds of scenes. This is why I do all my own encodes using H.263. See the support files for more details.

4. N-VOPs - This is the rather interesting thing I discovered, that, to my knowledge, no one else has discovered. The Philips 642 seems not to recognize N-VOPs...in other words, it just skips right over them. This leads to audio synch problems. The audio can be brought back in synch by fast forwarding or rewinding a few frames, but then it will go back out of synch the next time it encounters more N-VOPs.

Look at the number of N-VOPs. Keep in mind that everytime the player hits an NVOP, the audio will get out of synch...if your avi has more than 1 or 2 N-VOP's, you'll probably want to re-encode the AVI if you want it to play back in synch on the Philips 642.

If you have a different player, it may play N-VOP's just fine, so test it out with the file that I supply in the support files.

Don't use GSpot to figure out if you file has N-VOP's...GSpot will say that all packed bitstream AVI's have N-VOP's whether they do or not!

Diagnosing your AVI with GSpot

MPEG4Modifier is great, but the one thing it doesn't tell you about is how your AVI is interleaved. Interleaving tells you how the audio is mixed with the video. This isn't important for playback from a hard drive, but it is important when you are playing it off of a CD or DVD. GSpot will tell you how your AVI is interleaved.

A. Audio

Look in the "Codec" field and see whether your AVI has MP3 or AC3 audio. If the audio is something else, then you will have to re-encode the audio if you want to play the AVI on the Philips 642. Re-encoding audio is easy, but is beyond the scope of this guide.

B. Container

The container should be either "AVI v1.0" or "OpenDML (AVI v2.0)". If it is anything else, then you should re-mux the avi.

There should be a line labeled "Interleave:". If there is not, then your audio is not interleaved with your video and you need to re-mux the avi.

"preload" should be around 500. If it is 300-600, then great. If it is not, then you should re-mux the avi.

The other part of the interleave parameters depends on what kind of audio you have.

1. MP3 Audio

For MP3 Audio, it should be set to "1 vid frame"

2. AC3 Audio

For AC3 Audio, it could be set to "1 vid frame", but this is not preferred, and may or may not lead to "stuttering" at various points in the film.

For AC3 Audio, it should be set to "64 ms"

Re-muxing your AVI with VirtualDubMod^?

1. Open AVI in VirtualDubMod^?. 2. If you get some kind of warning about VBR header, and it asks the question "Do you want to rewrite the header?", then say "No". 3. Select "Video - Direct Stream Copy" (i.e., direct stream copy in the "Video" menu) 4. For AC3 audio, select "Streams - Stream List"...Right-Click on the AC3 audio stream...Select "Interleaving..." from the pop-up menu...choose to interleave audio every 64 ms (remember to click the "ms" radio button). Then exit out of the dialog and the stream list (i.e., hit "OK" twice). 5. Select "File - Save As..." 6. Specify a new file name, and click OK.

Making a test sample of your AVI with VirtualDubMod^?

There's no need to burn the whole AVI just to test it out in your standalone -- make a sample! Keep in mind though, that the sample is "re-muxed", so just because it plays perfect in your standalone doesn't mean that you don't need to check the interleaving of the original AVI with GSpot!

1. Open AVI in VirtualDubMod^?. 2. If you get some kind of warning about VBR header, and it asks the question "Do you want to rewrite the header?", then say "No". 3. Select "Video - Direct Stream Copy" (i.e., direct stream copy in the "Video" menu) 4. Select "Video - Select Range"...in the "Frames" column, set the length to 3000, then exit out of the dialog (i.e., hit "OK"). 5. Select "File - Save As..." 6. Specify a new file name, and click OK.

Re-encoding your AVI

This isn't difficult, but is beyond the scope of this guide. One day I'll write a re-encoding guide!

Support Files

I have a variety of little avi clips that will let you test your standalone, and see examples of various AVI problems and incompatibilities. Information is in a separate read-me file.

Tips

1. If you have more than 1 physical hard drive in your computer, then when you modify an avi, or re-mux an avi, you should choose a destination folder which is not on the same physical hard drive as the source. This will make the process a lot faster.

2. Unless you do a lot of encoding, you probably want to go into the VDubMod^?'s preferences and set "Direct Stream Copy" as the default video processing mode...that way you won't have to set that option every time.

About the Guide

A lot of this I learned from an awful lot of trial and error. I hope you guys find this to be useful information!

Lisa B.

-- KevinJarnot - 21 Jun 2005
to top