MPEG2/MPA audio doesn't sync with video...

[darknavi]

I capture using powervcr in MPEG2 format,then I use DJRumpy's DVD to XviD Conversion guide to convert the MPEG2 to avi(xvid) but when I try to add the audio,it doesn't go in sync with the video.

I followed everything on the guide except I am left with a .MPA file after using DVD2AVI. I open it using goldwave,time warp it to the same length as the video then save it as wav and finally add it to the encoded video(xvid) using vdub.

Can somebody please help?

[darknavi]

Can anyone help? I been waiting almost a month now

[iantri]

PowerVCR produces terrible non-compliant MPEG streams. If there are frame drops, it causes audio desync when edited. PVAStrumento can fix that. See step three of this guide.

I'm curious, however, as to why you would do this. PowerVCR has severe limitations (it can not capture the original interlaced video; it interpolates one field with great quality loss), and capturing to MPEG-2 will result in much loss of quality. The only time this would be desirable is if you want to do a quick one-off straight to DVD capture.

Why not just capture an AVI with huffyuv or an MJPEG codec, and then go from there?

[darknavi]

I want to capture in MPEG2 format since it kinda looks better and its smaller than AVI uncompressed although I capture MPEG2 at maxmium bitrate. I lose lots of frames whenever I capture with virtualdub. What is a good program to capture MPEG2 with?

[iantri]

In terms of technical quality (similarity to source), MPEG2 can never look better than uncompressed AVI. It may look better because the compression is masking the noise in the source, but this can be fixed with noise filters.

Capturing uncompressed AVI is extremely disk and processor intensive. Use the huffyuv or PicVideo MJPEG codec. huffyuv uses more disk space and is more processor intensive, but is non-lossy (it is compressed but in a way that retains the complete original image). MJPEG is similar to MPEG except compresses every frame equally. Settings of 18-19 in PicVideo give excellent (nearly identical to source) quality, with about 4gb/half hour disk usage. If you drop frames with huff, it may work better.

Virtualdub can be difficult to capture with. VirtualVCR (for WDM capture) or AVI_IO (for VfW capture) are both excellent.

If you still wish to capture MPEG-2, the Mainconcept Encoder is the way to go. It has a capture mode that allows capture in realtime to high quality MPEG-2. However, it is processor intensive. I can manage to capture 29.97fps 352x480 MPEG-2 video and MPEG-1 Layer II 224kbit audio with 0 dropped frames on an 850mhz Pentium 3, however I needed to tweak the quality settings down a bit.

Mainconcept encoder is USD$150 however.

A more powerful machine should be able to capture Full D1 (720x480). Just remember to set "top field first", which is what most capture cards are; MainConcept defaults to bottom field first.

[darknavi]

Whats the difference with "top field first" and "bottom field first"?

[iantri]

When the two fields that make up interlaced video are combined into one frame, they are interwoven with the one field being on odd lines, and the other field being on the even line, and so on.

Whether or not the first field goes on the odd or even lines depends on the capture card. Most capture boards are top field first. DV equipment is always bottom-field-first -- that is, the bottom (even) lines contain the field that goes first.

A visual aid (number represents which field is displayed first):

Top field first video: (field on odd lines displayed first)

1111111111111
2222222222222
1111111111111
2222222222222

Bottom field first video: (field on even lines displayed first)

2222222222222
1111111111111
2222222222222
1111111111111

Hmm.. all of a sudden this has gotten curiously off-topic for the audio forum .