VHS to DivX procedure

[mhs]

Hi

I´ve been trying to convert some vhs movies to divX.
My basic procedure is:
1. capturing with AVI_IO and PicVideo codec (mjpeg) quality 19, 640x480, 29.970 fps (My HD doesn´t have much space)
2. In Vdub I recompress to apply the following filters :Smart deinterlace, Crop and Noise reduction. In this step I use PicVideo again with the same settings.
3. In Vdub I compress with Divx 5, one pass quality based 85%,
MP3 128kpbs for audio.
My goal is to produce movies with satisfactory quality, record them in CDs and play them in my pc in full screen mode.

Now , I have some doubts:

1. Is it a nice procedure?
2. When we use filters, they are applied before or after the compression?
3. If they are applied before the compression, I think I can eliminate the second step and apply the filters during the divx compression, right?

Thankx for the help

[khp]

Your second step does seem a bit unnessesary, as you said, you may just as well apply the filters in the 3 step.

2. When we use filters, they are applied before or after the compression?

I'am not entirely sure what you mean by this, but basically recompression with filtering in virtualdub works as follows

1. uncompress source frame
2. apply filters to uncompressed frame
3. compress frame

3. In Vdub I compress with Divx 5, one pass quality based 85%,

I probably would'nt use quality based encoding, IMHO 2-pass encoding is the way to go.

[mhs]

Thank you khp, you cleared some doubts.

"I probably would'nt use quality based encoding, IMHO 2-pass encoding is the way to go."

Why don´t you use quality based encoding?
What is IMHO 2-pass encoding?
Doesn´t the 2-pass entire process take a longer time?

[khp]

Qualitybased encoding uses a fixed quantizer, which means that all frames will be encoded at the same quality level, but because quality issues are more noticeable durring low motion scenes than high action scenes, it's usually a good idear to use higher quality frames on low motion than high action scenes. 1 and 2-pass bitrate controlled encoding will give more quality to the low action scenes, while it also gives us a measure of filesize predictability, which is impossible with quality based encoding.

IMHO is short for 'in my humble opinion'.

And yes ofcause 2-pass encoding takes longer, but given the quality gains, I consider it to be time well spent (I usually let my pc do the encoding while I'am sleeping or at work, so I don't really care how long it takes)

[mhs]

Thankx again
Since I´m not familiar to 2-pass encoding, I have some doubts yet:
Do I have to maintain the same settings for video and audio in both phases?
In which pass are the filters applied?

[Enchanter]

With DivX5 2-pass, the only major thing you can change is the bitrate. Pretty much the rest (eg. resolutions, brightness, etc.) should remain unaltered.

The filters are applied on both passes.

[mhs]

I have done some encoding tests with 5-minutes clips captured from vhs and I think there is no difference in quality between 1-pass, 1-pass-quality-based and 2-pass encoded files with THE SAME SIZE.

So, could anyone answer me:

1. Do I have to check my eyes? or...
2. It is right, because the low quality of the source (vhs) I´m not able to see difference between them.

[Enchanter]

Sometimes you can hardly see a difference in quality between 1-pass and 2-pass, but for most of the other time, 2-pass is always superior because it can take away bits from low-motion scenes that do not require much and give them to high-motion scenes, which will definitely require much.

In your case, it is probably the low-quality (as you said) of the source. It is low-quality so that the codec does not have much difficulty compressing it. However, if you have the time, I always recommend the use of 2-pass because it ensures maximum quality within the smallest amount of space.

[mhs]

Thanks for your reply enchanter.

If I understood, you mean that the differences will be noticed basically on fast motion scenes. Ok?

[Enchanter]

Most of the time, yes.