Quality vs. Compression
- Keeper of Hellfire
- Joined: Sun Jan 09, 2005 6:13 am
- Location: Germany
For my first vid I tried to get as small a possible and was proud to get a 3:16 min vid at around 18MB, including the audio. The quality of course isn't that good.
Now I make calculations on the amount of raw data. I use the formula "resolution x 24(bit RGB color depth) x fps". For example, a 512 x 384 vid at 24 fps gives 108 MBit/s raw data. With MPEG4 codecs like DivX or XviD a compression around factor 100 is possible without remarkable quality loss. In this case my first attempt would be 1 MBit/s. Depending on how it comes out, I would try up to factor 150 or down to factor 75.
For the audio compression I'd never go below 128 kBps MPEG3. For Rock/Pop, 160 kBps is enough. If I one day should decide to do something to classical symphonic music, I'd encode it with 320 kBps.
I'm thinking about making small resolution versions for dial up users too. But i have to find a place where I can host it.
Now I make calculations on the amount of raw data. I use the formula "resolution x 24(bit RGB color depth) x fps". For example, a 512 x 384 vid at 24 fps gives 108 MBit/s raw data. With MPEG4 codecs like DivX or XviD a compression around factor 100 is possible without remarkable quality loss. In this case my first attempt would be 1 MBit/s. Depending on how it comes out, I would try up to factor 150 or down to factor 75.
For the audio compression I'd never go below 128 kBps MPEG3. For Rock/Pop, 160 kBps is enough. If I one day should decide to do something to classical symphonic music, I'd encode it with 320 kBps.
I'm thinking about making small resolution versions for dial up users too. But i have to find a place where I can host it.
- Infinity Squared
- Mr. Poopy Pants
- Joined: Wed Aug 11, 2004 10:07 pm
- Status: Shutting Down
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Meh... one of my incentives for downloading videos nowadays seems to be towards a bigger file size (rather than the small one that many people seem to value more)...
Yeah, well, I have bandwidth to spare, so I figure, why not make use of it... we all know that downloading here is a gamble in terms of entertainment factor, but why degrade the experience further by not going for the bigger sized (and hopefully at least better quality) videos when you can anyway.
I'm a stickler for quality... as others have said here, I make more than one render for my videos... one that will fall under the limits in the org, and one or two others for my own personal viewing pleasure and perhaps for the convention scene.
Yeah, well, I have bandwidth to spare, so I figure, why not make use of it... we all know that downloading here is a gamble in terms of entertainment factor, but why degrade the experience further by not going for the bigger sized (and hopefully at least better quality) videos when you can anyway.
I'm a stickler for quality... as others have said here, I make more than one render for my videos... one that will fall under the limits in the org, and one or two others for my own personal viewing pleasure and perhaps for the convention scene.
- WhereNext
- Joined: Sat Nov 23, 2002 9:17 pm
- Location: Indpls, IN
320 kbps isn't really necessary, even for classical music. You can go down to 256kbps and the only frequency loss you get are typically frequencies the human ear has lost, considering they say by age 12 the hearing frequency range drops from 20 Hz- 20KHz, to 20 Hz- 16/17 KHz. And more often than not, you can drop your mp3 down to 192 kbps and not be able to hear the difference, plus there are tricks you can do to your audio to compensate for frequency loss so you can still get that full sound out of a smaller bitrate mp3(like EQs to boost the frequencies lost in the encode, normalize, and compression).Keeper of Hellfire wrote:For the audio compression I'd never go below 128 kBps MPEG3. For Rock/Pop, 160 kBps is enough. If I one day should decide to do something to classical symphonic music, I'd encode it with 320 kBps.
As far as my encodes go, i like to try and stay between 10-15 MB/min depending on what the video calls for, and 128-192 kbps Mp3 for the audio.
- FoxJones
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- Flint the Dwarf
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