MPEG1 VCD authored as DVD work incorrectly?

[arminio]

I tried to author VCD MPEG1 video as DVD using DVDMaestro and resulting video is fine except playback problem (I tested playback on PowerDVD) in a botom part of screen - approx 1/3 of picture occasionally jitter during playback. Original VCD and MPG files used to author DVD are fine.

I also tried with Scenarist but it didn't want to open MPEG1 files at all...

Any ideas why this is happening?

[gircobain]

The DVD spec allows for MPEG1 video at 352x240/29.97fps (NTSC) and 352x288/25fps (PAL)
Things that won't work with this configuration: 16:9 AR, 3:2 pulldown for 23.976fps streams, VBR streams
Also, it seems that max bitrate for MPEG1 streams is 1856kbps
http://www.mpeg.org/MPEG/DVD/Book_B/Video.html
http://www.videohelp.com/dvd

[arminio]

I know all that... It is standard PAL VCD - MPEG1 352x288. I Re-encoded audio in standard AC3 (48Khz 224bps) . Maybe that is problem? Maybe audio need to stay MP2?

I dont know is MPEG file VBR or CBR...

Or DVDMaestro can't do this propperly?

I noticed that resultling IFO has info that video inside VOB is MPEG2 encoded instead MPEG1... I don't know how IFO need to look after this so I suspected that there is a problem and I changed that using IFOEdit but probem with playback is still present...

:(

[Delphin]

I know all that... It is standard PAL VCD - MPEG1 352x288. I Re-encoded audio in standard AC3 (48Khz 224bps) . Maybe that is problem? Maybe audio need to stay MP2?

I dont know is MPEG file VBR or CBR...

Or DVDMaestro can't do this propperly?

I noticed that resultling IFO has info that video inside VOB is MPEG2 encoded instead MPEG1... I don't know how IFO need to look after this so I suspected that there is a problem and I changed that using IFOEdit but problem with playback is still present...

:(

I know this thread is a little stale but for the benifit of anyone else experiencing a similar problem . . .

I had a similar issue with my PHILIPS stand-alone DVD player. This player can play just about everything including DIVX but when I tried 25 FPS MPEG2 authored to the DVD specs it would JITTER and STUTTER about once a second.

The solution was to un-mux the audio from the video and apply pulldown to the video stream to correct it to 29.97 using Donald Grafts excellent DGPulldown tool . . .

http://neuron2.net/dgpulldown/dgpulldown.html

This tool re-writes the time stamps in such a way that the duration of the video does not change, just the frame-rate, so you usually will not have to worry about your audio going out of sync:) Just re-mux the streams back together after the pulldown is applied and everything should be fine.

Not sure if this tool specifically would have helped in the above case because it can only process REAL MPEG2 streams, but I think that Aminio's suspicion about the player being fooled by the AC3 audio and treating the video as MPEG2 was probably correct.

MPEG1 video does NOT make provisions for pulldown so a few NTSC players will go ahead and do the frame rate padding for you on PAL vcd's, but apparently, because MPEG2 video DOES support pulldown, the same players may EXPECT that MPEG2 videos which look like they are in DVD format will be PULLDOWN corrected to 29.97fps.

STRANGE.

The above dgpulldown tool is one of the only ones I have found that can handle non-standard pulldown corrections like 25fpsPAL > 29.97fps NTSC so if you run into a similar problem give it a try.

[arminio]

I used pulldown but only on MPEG2 streams - never on MPEG1... interresting idea!
I'll try it. In the mean time, I used DVD-Lab for authoring - it work fine with MPEG1 videos...

[Delphin]

I used pulldown but only on MPEG2 streams - never on MPEG1... interresting idea!
I'll try it. In the mean time, I used DVD-Lab for authoring - it work fine with MPEG1 videos...

Sorry, I thought I mentioned that I did not think the DGPulldown tool will work with MPEG1 because the MPEG1 standard doesn't even support pulldown as far as I can tell. So I think you have to transcode to MPEG2 352x240 to use
DGPulldown, which would be as big a hassle as re-encoding the audio.

It's good to know that DVD-Lab worked for you. I am always interested in looking at a new authoring tool, though at the price they are quoting it's a bit more than I wanted to spend for a 'home authoring' tool.

The only final comment I would make is that it's a little risky to 'mix standards' (like using AC3 audio in a otherwise VCD compliant stream). I have done simalar 'mix and match' things in the past and it always seems to create problems later.

The big risk is that after you finally do get it to work with your current hardware, later that player dies and you find to your horror that you can't find a replacement player that will play any of your 'custom' encoded disks.

So whenever I change anything about how I author a DVD I always try the resulting disk out on SEVERAL PLAYERS looking for the best compatiblity.

I wonder, did DVD-Lab "save you from yourself" and quietly re-encode the audio track? Did you check the resulting VOB's to see if they are still 'mixed mode' with MPEG1 video but AC3 audio. (maybe DVD-Lab re-encoded the audio to the VCD audio spec?)

[arminio]

They are mixed but DVDlab marked video stream as MPEG2. Pretty interresting...
And during demuxing proces of original MPEG1 file, DVDLab asked me to re-encode audio (for 48Khz). I preffered AC3 and resulting IFOs are the same in both cases (marked as MPEG2 no mater if I used AC3 or MP2 audio).

I am aware of possible problematic playback on some players and without re-encoding into real MPEG2 stream, nothing is 100% sure.

[mpucoder]

There is nothing wrong with using AC3 and MPEG-1 video in a DVD. However once in DVD-Video format the framerate must match the television standard or the video will stutter. This is unlike VCD, which can do simple framerate conversions (repeat or drop a frame). So any stuttering is caused by a problem in the video, and not the audio.

Converting from mpeg-1 to mpeg-2 video is very simple and can be done "on the fly" to take advantage of mpeg-2 features, such as pulldown. This is probably what happened when DVDLab sensed that pulldown was needed.

[arminio]

>There is nothing wrong with using AC3 and MPEG-1 video in a DVD. However once in
>DVD-Video format the framerate must match the television standard or the video will
>stutter. This is unlike VCD, which can do simple framerate conversions (repeat or drop
> a frame). So any stuttering is caused by a problem in the video, and not the audio.

Drop-frame is normal way to convert NTSC to PAL during playback on lot of players and not only for VCD.

>Converting from mpeg-1 to mpeg-2 video is very simple and can be done "on the fly"

MPEG2 decoders shuold decode MPEG1 streams also - but who knows are they implemented that way in all players.

[Arky]

Don't forget that a further consideration when re-purposing VCD MPEG1 streams for DVD formatting is that VCD allows longer MPEG1 GOP lengths than DVD does, irrespective of frame size and bit-rate considerations. Many players will tolerate playback of VCD MPEG1 streams that have been muxed into DVD format VIDEO_TS folders, but others will choke when they realise that the GOP length is inappropriate for the muxed format, and thus that the multiplexed DVD is not Spec'-compliant.


Arky ;o)

[mpucoder]

MPEG2 decoders shuold decode MPEG1 streams also - but who knows are they implemented that way in all players.
All players are required to decode mpeg-1 at 352x240 (NTSC) or 352x288 (PAL). Other frame sizes of mpeg-1 are not permitted.

[arminio]

>All players are required to decode mpeg-1 at 352x240 (NTSC) or 352x288 (PAL). Other
>frame sizes of mpeg-1 are not permitted.

I know that - this is VCD standard. But I am not sure that all players are required to play VCD video authored as DVD...

[mpucoder]

I was talking about DVD-Video. VCD was added later to players, and not all players support it. But if it is a DVD-Video player it is required to play 352x240 or 352x288 mpeg-1

[Prodater64]

I was talking about DVD-Video. VCD was added later to players, and not all players support it. But if it is a DVD-Video player it is required to play 352x240 or 352x288 mpeg-1


In other words, mpeg1 352*240/288 "is dvd standard".

Allowable picture resolutions are:
MPEG-2, 525/60 (NTSC): 720x480, 704x480, 352x480, 352x240
MPEG-2, 625/50 (PAL): 720x576, 704x576, 352x576, 352x288
MPEG-1, 525/60 (NTSC): 352x240
MPEG-1, 625/50 (PAL): 352x288

http://www.dvddemystified.com/dvdfaq.html#3.4