Video Compression

Anyone know the best way/program to use to to reduce the file size of a video but still keep decent quality? a 20 minute video I upload is average 300mb. But I've seen 40min long 300mb videos with same quality.

Any advice?

winavi. Keep your bitrate no less then 2000 and keep the aspect ratio the same as the file to be shrunk.

This will give acceptable results, bigger the bit rate, better the quality but larger the file, but experimant, depends what your shrinking from, mvk, dv, avi, wmf

(30-09-2012 22:14 )mellover Wrote:  winavi. Keep your bitrate no less then 2000 and keep the aspect ratio the same as the file to be shrunk.

2000 bitrate seems enormous. I'm not familiar with tv sources but from what I've seen most webstream vids on here are encoded around 600-800kb/s.

It may be a little outdated now but this thread has been pretty useful for me in the past.
http://babeshows.co.uk/showthread.php?tid=29356

It would help if you at least tell us which operating system you are using if you want software recommendations.

I used avidemux for my vids, available for both windows and linux. It has pretty good options for controlling the output, and you can cut the vid as you encode, and even set it to split the output file into multiple files of a given size.
Currently, I try to use MeGUI on windows, but it doesn't handle all vids I try it on.
Handbrake is another good freeware offering, but I never really got along with it, and it has limited output options which don't really work for me.
On windows, Super is another one worth a look. it is plain ugly to look at, and can take some time to work out the right settings, but when you get it right, it can do a decent job.

The biggest factor on file size/quality will be the codec you use. I always used xvid as it is pretty universal, and gives good compression, and I have some older kit here that needed an older codec like this, but most people nowadays are using H264 which should give better results.

(30-09-2012 23:49 )oklahoma001 Wrote:  2000 bitrate seems enormous.

Not really, but if you want good quality without the blocky look, your really went that. Web streams and stuff are quite poor quality.

I suggest this to you. down load a large MKV file at least a gig.

Put it in winavi. Bitrate 2000, ratio 1280X720 (for wide screen), audio 320 and you'll see it will reduce it in half with very little loss of quality.

(01-10-2012 02:22 )mellover Wrote:  ...
I suggest this to you. down load a large MKV file at least a gig.

Put it in winavi. Bitrate 2000, ratio 1280X720 (for wide screen), audio 320 and you'll see it will reduce it in half with very little loss of quality.

Maybe so, but what is the bitrate and codec of the incoming file, and what is the codec being used for the outgoing file? If the bitrate and codec of the incoming file are the same, then it won't reduce at all.
Those files you are downloading at that kind of size are probably encoded to a high quality (at a guess, 10000kbps and 1920), which means that yes you can most likely re-encode them to a lower quality with little noticeable loss (depending where you are playing them back), but that won't be the case with all vids.

(01-10-2012 07:45 )munch1917 Wrote:  

(01-10-2012 02:22 )mellover Wrote:  ...
I suggest this to you. down load a large MKV file at least a gig.

Put it in winavi. Bitrate 2000, ratio 1280X720 (for wide screen), audio 320 and you'll see it will reduce it in half with very little loss of quality.

Maybe so, but what is the bitrate and codec of the incoming file, and what is the codec being used for the outgoing file? If the bitrate and codec of the incoming file are the same, then it won't reduce at all.
Those files you are downloading at that kind of size are probably encoded to a high quality (at a guess, 10000kbps and 1920), which means that yes you can most likely re-encode them to a lower quality with little noticeable loss (depending where you are playing them back), but that won't be the case with all vids.

I'm using Windows Vista. I record straight from TV and get the following;

File type: MPEG Movie
Image Size: 544 x 576
Pixel Depth 32
Frame Rate: 25
Average Data Rate: 244kb / second

(01-10-2012 07:45 )munch1917 Wrote:  abut that won't be the case with all vids.

I never said it did, but the op gave no imformation so i gave general advice.

I shall be quiet from here on in and leave it to you.

I use Ashampoo® Movie Shrink & Burn 3 & it's bloody cool

If you want i can give you the codes for it!

(01-10-2012 09:08 )techniques Wrote:  I'm using Windows Vista. I record straight from TV and get the following;

File type: MPEG Movie
Image Size: 544 x 576
Pixel Depth 32
Frame Rate: 25
Average Data Rate: 244kb / second

244kbps is quite low bitrate, that's more like the sort of bitrate you'd expect from a webstream.
If you can, I'd try increasing that slightly at the recording phase. Some of the vids I have here from other people are from 600 up to 1000kbps. That will give you a better quality to start with, and then you can work on reducing the file size and maybe even reduce that bitrate as you re-encode. Thing is, you can reduce the bitrate to get a smaller file with a slight reduction in quality, which may not be too noticeable, but in my experience, you can't increase a low bitrate to improve quality when you re-encode. (not strictly true, there are ways and means of 'improving' a vids quality, but that is really beyond the scope of this discussion, just start with the best you can and work down from there. it's easier)

So, whatever the bitrate, I'd generally recommend don't try to re-encode it with anything higher than what it already is, and if it's that low, leave it as is, don't want to take it any lower.
As mentioned before, the real thing here is the codec. Your info doesn't mention which codec you are using there.
You might want to get MediaInfo :
http://mediainfo.sourceforge.net/en

This handy util gives information on the codecs used in media files on your pc (goto the download page and select the version without installer, as I recall they package it with those pesky IE toolbars or some other crapware).

To re-encode, I'd suggest you have a good read of this thread about avidemux ;

http://www.babeshows.co.uk/showthread.php?tid=26385

That gives a very good guide to get you started, though you may need to tweak the settings still to get best results with your files. Avidemux is available as a portable app for windows, no installation necessary, so it won't cause any harm to your pc, just unpack it and run.

To tweak the settings, when you have chosen the codec, you click the configure button. The main thing is in the General tab, under 'encoding mode'.
The default is usually single pass, with a slider below that you use to configure the quality level. I usually switch to Average Bitrate (two pass) to give a better quality, but this takes longer to process. You also need to set the bitrate then. In your case, start with the same bitrate as the original file. Alternatively, you might want to play with the other options instead and see what works for you.
With avidemux, you can select only part of the file to encode, so you can experiment by selecting just a few minutes of a vid to work with, rather than process the entire file. Use the default settings and copy the file somewhere safe, then change some settings and encode again, and compare the result with the default. Keep playing with settings, comparing the quality of the resulting file, as well as the relative file sizes until you get something that works for you, then try it on the whole file.