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swingheim · 03-28-03, 06:30 PM

The other thread was getting quite long, and since this was not a complaint, I wanted to post it anew, and hope it might be of benefit to others.

-= section 1 =---------------
To increase the speed of the encoding, since we are doing multi-pass encoding, I would think that you would not have to re-encode the audio twice. So, ignore the audio options (do a straight copy) for the first pass, and then re-encode the audio on the second pass. That should save a little time. I haven't tested this yet... but will shortly.

-= section 2 =---------------
If you have a wide-screen movie that doesn't fit the 4:3 aspect ratio, you can add those black strips across the top and bottom of the video to get the 4:3 ratio.

Example:

Source video is 704x336, and I want the result to be 320x240. If I straight resize the video, everyone will look "squashed". So, lets add those black stripes above and below the video:

VirtualDub makes this easy to do. We simply calculate the resized video as such:

704:336 = 320:X
Solve for X: 320 * 336 / 704 ~= 152. In our RESIZE video filter, we say we want our video to be 320:152, then check the box below, and say we want the resultant video to be 320:240.

-= section 3 =---------------
Video will laaagg behind the audio when it cannot draw the frames fast enough.

I had a similar problem with my laptop: if I didn't have DMA enabled for the DVD drive, the DVD disc could not be read fast enough to keep up with real-time playback. It is similar with your Axim.

The solution? Free up system resources. Make sure no programs are running in the background, and check to make sure your unit has enough RAM to properly cache the video. If your video is lagging behind 15-20 minutes into your movie, odds are you don't have enough free RAM. Free some up.

I haven't thoroughly tested VirtualDUb yet, but a general rule of thumb: free up your machine's resources when encoding video. It is VERY CPU intensive, and if you are running other programs in the background, it could (again I haven't tested it yet) cause errors inyour encoding. Remember the early days of CD-burners? If you launched PhotoShop/Word/Excel/Quake3 while burning a CD, the read-ahead buffers would not get repopulated, and you would get a buffer-underflow error.

-= =-------------------
I have a 2.4 gHz machine with 1 GB RAM, and I am encoding video at around ~4x.

I know I might have touched on things in previous posts, and apologize if you feel this post was too repetitive.

03-28-03, 06:30 PM	#1 (permalink)
swingheim Aximsite Rookie DAP Freshman Join Date: Mar 2003 Location: Orem, UT Posts: 43 Thanked 0 Times in 0 Posts	More on DivX Encoding for the Axim The other thread was getting quite long, and since this was not a complaint, I wanted to post it anew, and hope it might be of benefit to others. -= section 1 =--------------- To increase the speed of the encoding, since we are doing multi-pass encoding, I would think that you would not have to re-encode the audio twice. So, ignore the audio options (do a straight copy) for the first pass, and then re-encode the audio on the second pass. That should save a little time. I haven't tested this yet... but will shortly. -= section 2 =--------------- If you have a wide-screen movie that doesn't fit the 4:3 aspect ratio, you can add those black strips across the top and bottom of the video to get the 4:3 ratio. Example: Source video is 704x336, and I want the result to be 320x240. If I straight resize the video, everyone will look "squashed". So, lets add those black stripes above and below the video: VirtualDub makes this easy to do. We simply calculate the resized video as such: 704:336 = 320:X Solve for X: 320 * 336 / 704 ~= 152. In our RESIZE video filter, we say we want our video to be 320:152, then check the box below, and say we want the resultant video to be 320:240. -= section 3 =--------------- Video will laaagg behind the audio when it cannot draw the frames fast enough. I had a similar problem with my laptop: if I didn't have DMA enabled for the DVD drive, the DVD disc could not be read fast enough to keep up with real-time playback. It is similar with your Axim. The solution? Free up system resources. Make sure no programs are running in the background, and check to make sure your unit has enough RAM to properly cache the video. If your video is lagging behind 15-20 minutes into your movie, odds are you don't have enough free RAM. Free some up. I haven't thoroughly tested VirtualDUb yet, but a general rule of thumb: free up your machine's resources when encoding video. It is VERY CPU intensive, and if you are running other programs in the background, it could (again I haven't tested it yet) cause errors inyour encoding. Remember the early days of CD-burners? If you launched PhotoShop/Word/Excel/Quake3 while burning a CD, the read-ahead buffers would not get repopulated, and you would get a buffer-underflow error. -= =------------------- I have a 2.4 gHz machine with 1 GB RAM, and I am encoding video at around ~4x. I know I might have touched on things in previous posts, and apologize if you feel this post was too repetitive. Last edited by swingheim; 03-28-03 at 06:35 PM.