need encoding help

tbush wrote on 12/3/2005, 6:02 PM
Hi,
I have a Pentium 4 dual processor with 2 gigs of ram. I was rendering a small video out of Vegas...making a wmv file to put on a data cd for my son to view. The video played fine on my computer, but played very choppy on his. He said it was because my computer was fast and his was slower. His computer is a Pentium 3, but is lacking in memory. I tried to play it on my ibook and the same thing happend,,,it played but it was choppy. That doesn't make sense to me. If I render something out then it should play on another computer without being choppy. It was only about 250 mb. Can anyone give me any suggestions? When I encode to a DVD into Architect...it plays fine on my sons computer. I would like to fix this problem, but I am not sure how. Thank you, Tara Bush

Comments

jrazz wrote on 12/3/2005, 6:21 PM
1. Copy the file from the cd to the computer and it should play a lot faster. There are a lot of different variables to take into consideration. The CD drive could be slow (it is a pentium 3 therefore the cd drive could be slower in speed), couple that with low system memory, a lot of background programs running and resources being eat up trying to decompress the wmv file on the fly and it could very well be choppy. So, first try copying it to the hard drive from the cd to see if that speeds things up, close out background programs on the taskbar (to the right- all the icons next to your system clock). If he is running windows xp and it only has 128mb of ram, then everything should be slow and it would be very beneficial to step up the amount of ram that he has.

2. You could try encoding it at a lower bitrate.

Hope this helps,

j razz
tbush wrote on 12/4/2005, 10:12 AM
Thank you very much for the suggestions. Could someone tell me if there is a direct relationship re: encoding on a fast computer and playback problems on a slower computer....I mean does it matter whether or not you are encoding on a fast computer or not? I have to send clients video documentation on a data cd, and I need to make sure they are going to be able to play it back without problems, and I don't know how fast their computers are.
MH_Stevens wrote on 12/4/2005, 10:31 AM
The rendered file does not "know" what type or speed of machine made it. As told you above bit rate will be significant especially if your clients or relatives wish to play the video from the CD rather than the HD. Experiment rendering with different bit-rate setting. Have you tried to play the DVD on your computer as opposed playing it from your HD? I have a fast machine with a fast DVD player and I can not play a smooth "wm9" rendered at the default settings except from the HD.

Chienworks wrote on 12/4/2005, 10:40 AM
Generally, if i know the video will be played from a CD i try to keep the bit rate around 2500Kbps max. If it will be played from a data DVD i try to keep it at 3500Kbps max. Most of the computers i've used for playback can have difficulty keeping up full speed playback without stuttering if i go above these rates. If i need to use a higher bitrate i'll copy the file to the playback computer's hard drive first. From the hard drive anything faster than a 700MHz cpu should be able to handle bitrates of 15,000Kbps or more.
tbush wrote on 12/4/2005, 3:38 PM
I am not sure if this message will be posted twice, but the first time I replied it didn't show up. I just wanted to thank you so much for the responses. It is really a big help. I will experiment with the different bit rates to see what works best. Best regards, Tara Bush
tbush wrote on 12/7/2005, 6:49 AM
Hi again, I am trying to experiment with the bit rates when rendering out of Vegas. Say I wanted to encode a short video to send over the web for someone to download. Would I use the encoding bit rate suggestions given before for computer hd playback? Also, when I am at the render as window, and I select the WMV template.......actually, I am not quite sure what to select. Which mode is best for downloading from the web and computer playback...CBR, CBR (two pass), bit rate VBR (Peak), quality VBR, or bit rate VBR. Each of these gives me different selections. Only the CBR modes allow me to chose a selection out of the bit rate window and none of these go down to 15,000Kbps or below.....the lowest is 22,000. I know this is a lot to ask, but I really can't find much help in the Vegas help section. Can you lead me to a publication that might explain more of the encoding for Vegas. I bought the Vegas Seminar Series, but I am not finding any of that information there either. Thanks for your help, Tara Bush
Chienworks wrote on 12/7/2005, 7:06 AM
First of all, be mindful of the "K" in "Kbps", which means 1,000. 15,000Kbps = 15,000,000bps and 22,000bps = 22Kbps. So 15,000Kbps is much higher than 22,000.

When you are posting something on the web you need to decide if you want them to be able to watch it in a timely fashion and sacrafice a lot of quality, or if you want them to spend a few days downloading it to get DVD quality. 10 minutes of video at 256Kbps will create a file about 19MB. 10 minutes of video at DVD quality (around 6000Kbps) will be around 456MB. 19MB can be downloaded in a couple of minutes on a broadband connection and probably in half an hour over dialup. 456MB could take 30 to 60 minutes on broadband and probably 20 to 40 hours over dialup. Depending on where and how you post your video on the web, you may not have space available or be able to afford a 456MB file.

What i do is choose the WMV template that is close to my desired output, usually 256 Kbps for web or 3 Mbps (M = 1000000) for CD. Then under the Custom / Video tab i choose Bit rate VBR (Peak). Under this selection you can type in the bitrate you want to use. Average bit rate will determine the size of the file. For 15,000Kbps you can type in "15 M", or for 6000Kbps type in "6 M", or for 500Kbps type in "500 K". I usually set the peak rate to be twice the average rate.

Lower bitrates result in a fuzzier image with more artifacts. In many cases 250 K is sufficient for web video. If you have a lot of action or fine details then 500 K may be useful but it will also double the file size. If you have lots of fine details but very little action you can consider reducing the frame rate to half speed. This will allow twice as many bits for each frame without having to increase the overall bit rate.

If you want the person on the other end to get a very high quality video and they don't mind spending many hours downloading it, and you can find a place that will cheaply let you post huge files, then by all means go for higher bitrates. If you want people to browse to your website and see some clips in real-time, then keep the bitrates very low.
tbush wrote on 12/7/2005, 7:17 AM
O.K. Thank you so much for your help. I will get started experimenting again with your suggestions.