how to set conversion rate of Kb/s in Virtualdub?

[texas1]

i have a massive video file about 600gb+ captured in AVI by Amarectv on my hard drive.
I want to reduce this to about 25-30gb by setting at 15000kb/s or 15mb/s.
I downloaded the x264vfw codec which vdub recognizes but the section about bit rate is greyed out.

So how do we set the bitrate when doing a "Save AVI"?

thanks

[El Heggunte]

but the section about bit rate is greyed out.

Are you sure of that?

[texas1]

where did you get that version of x264 ? I got mine from Sourceforge http://sourceforge.net/projects/x264vfw/

mine looks very different from yours

[texas1]

nevermind -- it's the ABR (not ratefactor based CRF) setting that is the key that allows for choosing the bitrate.
thanks much for your help!

[manono]

nevermind -- it's the ABR (not ratefactor based CRF) setting that is the key that allows for choosing the bitrate.
thanks much for your help!

Okay, but ABR encoding is a very poor choice. Either do two-pass encoding for an average bitrate or choose CRF single-pass encoding. Unless you don't care much for quality and speed is your only concern.

[texas1]

the default CRF single pass encoding set to 23.0 resulted in a very low bitrate. What is a proper setting to equate to 15mb/s?

does two pass encoding really make that big of a difference in quality? Only reason I ask is i've tried 2 pass in handbrake but didn't see any improvement over the regular 1-pass in handbrake. Just curious if it really improves anything.


-- just checked -- there is no "two pass" for X264 , only single pass or "multipass". And how many passes in multipass??

[jagabo]

In CRF mode you pick the quality and the encoder uses whatever bitrate is needed to deliver that quality. In bitrate mode you pick the bitrate and the encoder delivers whatever quality it can for that bitrate. They are two sides of the same coin.

With multipass bitrate based encoding you "encode" twice (or more times). First select the first pass and encode (the encoder just examines the video during the first pass), then select the N'th pass and encode (producing output from what it learned in the first pass). You can further refine the encoding with a third pass, forth pass, etc. (all N'th passes). You get very little improvement with more than two passes though.

[texas1]

In CRF mode you pick the quality and the encoder uses whatever bitrate is needed to deliver that quality. In bitrate mode you pick the bitrate and the encoder delivers whatever quality it can for that bitrate. They are two sides of the same coin.

With multipass bitrate based encoding you "encode" twice (or more times). First select the first pass and encode (the encoder just examines the video during the first pass), then select the N'th pass and encode (producing output from what it learned in the first pass). You can further refine the encoding with a third pass, forth pass, etc. (all N'th passes). You get very little improvement with more than two passes though.

thanks, the Multipass has 3 choices

Multipass - 1st pass
Multipass - 1st pass (fast)
Multipass - Nth pass

but how to control the N ? I don't want 13 or 14 passes obviously, just 2 is fine. How to tell it to only do 2 passes?

[jagabo]

VirtualDub doesn't automate mutipass encoding so you control the number of passes by manually running the number of passes you want. If you want a 2-pass encode you run the first pass (you might as well use the fast option as there's very little difference in quality when using fast or non-fast) then you run an Nth pass. That's two passes, you're done. If you want a third pass you run another Nth pass. If you want four passes you run Nth pass again. Etc. The encoder updates the log file with each pass so (theoretically) the resulting video gets progressively better and better with each pass. In reality there's not much difference beyond 2 passes.

[texas1]

thanks, I am running the Multipass - 1st pass option right now (not the "fast" one). I tried the Nth pass first but errored with can't find "stats" file or something which I believe is because I never ran the first pass.

One thing is that I aborted a test first pass.. and the resulting file only had audio . I suppose that is because the first pass is simply an "investigation" type thing that vdub goes through as you indicated. I have to do an N pass to get the actual video right? If i just stop after the 1st pass then all I have is an audio file I presume, correct?

[jagabo]

I tried the Nth pass first but errored with can't find "stats" file or something which I believe is because I never ran the first pass.

That is correct.

One thing is that I aborted a test first pass.. and the resulting file only had audio . I suppose that is because the first pass is simply an "investigation" type thing that vdub goes through as you indicated.

Yes.

I have to do an N pass to get the actual video right? If i just stop after the 1st pass then all I have is an audio file I presume, correct?

Yes.

[texas1]

thanks, I aborted the first pass and redid the first pass (fast) - per your advice.

Also set the bitrate to 15000 kb/s but the "projected file size" indicates 2677 mb which is just about 2.6GB but I need it to be 25-30GB since the original file is 600GB+ and about 4 hours of video which i know from past experiennce at 15mb/s translates to about 25GB.

Will the file actually expand to 25GB after the first pass (fast)? It's as if vdub is ignoring the 15000kb/s setting, is it?

[jagabo]

Since the video is not saved during the first pass the file will be small. And the bitrate during that pass is meaningless.

During the second pass you should start seeing the video grow to the expected size. But note that the projected size by VirtualDub may not be accurate until near the end. It only knows how many frames it sent to the and the encoder and how many bytes it output. It projects the final file size based on that. It has no idea what the encoder is going to do later in the video. So, for example, if your video starts out with all black frames then a bunch of still logos, all of which compress down to nearly nothing, VirtualDub will initially project a small final size.

[texas1]

well it finally finished at 25.3GB but no audio!! I wonder what I did wrong.

I then tried the Single Pass ABR bitrate method, to simplify things, but even that had no audio. What is my mistake?

[jagabo]

Did VirtualDub recognize the audio in your source file (File -> File Information)? Did you disable it (Audio -> No Audio)?

[texas1]

yes, seems to be there in File Information

-------------------

Video:
Frame size, fps (µs per frame): 1280x720, 59.940 fps (16683 µs)
Length: 1063396 frames (4:55:40.99)
Decompressor: UtVideo YUV422 BT.601 VCM (ULY2)
Number of key frames: 1063335
Min/avg/max/total key frame size: 116068/672889/1219012 (698737394K)
Min/avg/max/total delta size: 0/0/0 (0K)
Data rate: 322646 kbps (0.00% overhead)

Audio:
Sampling rate: 48000Hz
Channels: 2 (Stereo)
Sample precision: 16-bit
Compression: PCM (Uncompressed)
Layout: 12994 chunks (0.00s preload)
Length: 851568000 samples (4:55:41.00)
Min/avg/max/total frame size: 235008/262141/262144 (3326438K)
Data rate: 1536 kbps (0.01% overhead)

[texas1]

my original file 600GB+ renamed LARGE.avi. I ran a Single Pass bitrate based ABR (pictured) but had a bizarre result as 2 files were saved as output



1) a 31GB file with no audio named "vdub" as per my specifications in the picture (path not shown) (NO AUDIO has Video)
2) a 3gb file with no video that I had called "trial" and initiated when we do the Save as AVI to start the encoding. (NO VIDEO has Audio)


I had the video in Full Processing Mode, same with Audio which was no compression PCM. Should it be Mp3?

I just want a simple encode but this is much too complicated for simple tasks. What are the right configurations?

[jagabo]

Did you set x264vfw to output to VFW or to a file? If you did the latter you will get no audio in that file. VirtualDub should have saved the audio in another file.

[texas1]

yes, after I posted my last post a few minutes ago I realized the mistake that you also just indicated. That is why I had 2 files, one audio and one video (a much too complicated scenario for a novice)

So, I set everything to Load Default settings and am retrying now and it's going much faster.

I guess with so many options on Vdub, it can be confusing for a newbie, but so many options can also be a strongpoint of the application.

[jagabo]

The file produced directly by x264vfw can only contain video because the video codec doesn't receive any audio.