Original AVI to XVCD Duration time Difference.

[Teleport]

I'm puzzled.

I've just created a XVCD from a DivX using the guides on this site.

Encoded the mpeg using TMPGEnc as detailed here
https://www.videohelp.com/tmpgencxvcd.htm

Then burn using Nero a detailed here.
https://www.videohelp.com/neroxvcd.htm

Before I try to view it on my DVD player I thought I'd just have a look at it on my computer using WinDVD.

Something strange. The original duration of the DivX (and indeed the mpeg created by TMPGEnc) movie was 1hr 29m 31s when played using windows media player. But according to WinDVD it's now 1hr 16m 20s.

Both the beginning and the ending or the movie are there and the A/Vsync is fine.

Can anyone tell me whats going on please?

Also the mpeg I created with TMPGEnc had a file size of 761MB but still burnt to 700MB CD using Nero (video CD) with no errors.

Whats happenning?
Has it cut a portion out of the middle or something?
Am I going mad?

Thank you

[mats.hogberg]

To me, that sounds like you've encoded the movie at a higher frame rate than the original AVI. I'd guess original frate is 25, and you encoded at 29.976 fps?
As to how much space there is on a CD: 80 min CD holds about 800 MB data. Using it as a regular data disc, adds a lot of error correction bits&bytes, giving you about 700 MB left for the actual data. The way a VCD is burned, this error correction overhead is not used, so all available space can be used for data.

/Mats

[Teleport]

Thanks for the reply Mats.

Thanks for the info about the CD storage capacity. You learn something new every day . WOW a normal Data disc uses a whole 100MB for error correction! Seems a lot.

No, I used the correct frame rate (checked it in Gspot)

I did use VBR though. Would this account for the difference?
This shouldn't bother me as the XVCD sems to work (will test in DVD player tonight), but I just need to know whats happenning.

[mats.hogberg]

Well, if you've encoded at the same frame rate as the AVI (which you must have, I now see, as WMP reports the same duration both as mpg and avi), and nothing is missing, then either WMP or WinDVD is reporting the wrong value. VBR might confuse WinDVD, but not affect actual duration.

Time to take out the stop watch!

/Mats

[Teleport]

Ok, thanks Mats.

I'll premiere the movie tonight, set the stopwatch and keep an eye on the DVDs timer display.

Maybe it is winDVD at fault. I'll post with my findings.

One more thing. The original DivX audio Bitrate is 128. I have encoded it as 224. Is this a waste of space or a necessary measure to ensure my DVD player reads it correctly?

Cheers

[energy80s]

You are probably best to encode the audio at 224kbps - it is something of a standard in VCD terms (even though you are making an Xvcd) and the amount of space you would save in reducing it doesn't really warrant the possibility of the audio not playing correctly on the final disc.

[mats.hogberg]

Yes, 224 kbps audio is the VCD standard, but I often trade audio bitrate for video bitrate when trying to get as much quality as possible on one CD. Never lower than 128 kbps tho...
As my stand alone plays almost anything, I'm free to experiment to my hearts content.

/Mats

[Teleport]

Thanks both of you.

I think I'll give using a lower bitrate a try on a CD-RW.

I think I have now figured it out by looking at this page
https://www.videohelp.com/xvcd.htm

What you said about framerate matching kind of gave me a clue Mats.

The mpeg I encoded with TMPGEnc was 23.976fps but the standard for MPEG is 25fps so When I burn a Non-Compliant VCD with Nero it must be
fooling the player hence the descrepency.

What do you think?

[mats.hogberg]

I'd say: If your player / TV handles "anything", always encode at the same frame rate as the original. By far the least problems. If your TV and or player is NTSC or PAL only, and the AVI has "the opposite" frame rate, then you'll have to be prepared for some kind of frame rate conversion.
23.976fps is a valid VCD frame rate - NTSC Film.
The times I've done frame rate conversion (to/from NTSC Film from/to PAL) I've just changed the frame rate using avifrate (speeding up/slowing down the overall movie by about 4%) and shorten / stretch the audio (extracted as WAV before adjusting the frame rate) by the same amount.

/Mats

[Teleport]

My player can handle PAL or NTSC.

Where does this leave me with interlacing Mats?

[mats.hogberg]

Ouch! Really, I don't know! I've done one DVD rips that turned out looking awful, but after a little experimenting with different mehods for deinterlace on the Advanced tab in TMPGEnc (I's really beautiful - just go to a frame that suffers heavily from interlacing and select different deinterlacing methods until it looks fine!) it went away. Fortunately this was a music video, and I encoded each track separately.
That leads me to the rule: Always encode a short piece and check the result before starting a lengthy encoding pass!

/Mats

[Teleport]

sorry Mats,

What I meant is will I get better quality if I select Interlace or non-interlace as the encode mode in TMPGEnc?

[mats.hogberg]

Oh - I think (X)VCD (MPEG1) doesn't allow for interlace - this is one reason for MPEG2/SVCD. I maight be wrong tho... However, I've never given it any thought, actually.

/Mats

[Teleport]

LOL.

BUT WILL USING ENCODING WITH INTERLACE GIVE ME BETTER QUALITY PLAYBACK ON MY STANDALONE PLAYER?

[EddyH]

It's probably reading "disc" time rather than "playing" time... if you're really so bothered about it, play the video and use a stopwatch to see how long it takes the DVD program to count up, eg, from 5m00 to 6m00... likely it will take a minute and a couple of seconds, rather than 60s dead.

My DVD player does this a lot, with lower-rate CBR, or VBR material (in which case it goes both slower, *and* upto 2x faster in complex scenes - if you've used VBR then choose your test point with care, you may have to use the whole movie ).... the counter (for VCD anyway) wouldn't be able to go beyond 99 minutes even if it counted play time. I don't worry about it, the best I can do is to use the timer as a "percent progress" meter instead of absolute time. As it all evens out in the end, I just, say, instead of searching to 30m00 out of a 120m film, search to 20m - 1/4 of the 80m disc just as 30m is 1/4 of two hours. It's not brilliantly accurate if I'm using average BR ~750k instead of CBR ~750k, but does the trick.