Video File Sizes

there confusion, or questions, on why 1 video file format yields larger, or smaller file sizes, 1 does. answer is, on surface, simple, there many variables, make bit more difficult give definitive answer.

 

file size governed 2 factors, duration of timeline (how long "movie" is), , bit-rate of encoding. change in bit-rate directly affects perceived quality of file on playback, i.e. "visual quality." simple part.

 

however, 1 choosing codec encode/compress file. codec choice affect visual quality of output file, , resulting file size. duration set, bit-rate variable affect file size. codec's allow lower bit-rates (smaller file sizes), @ sacrifice of quality. there codec's, allow lower bit-rate, still provide adequate visual quality. few, divx , open source "cousin" xvid, plus mkv, job @ compressing file (lower file size), still providing quality. designed streaming media, , viewer must have them installed on computer, on in player, play resulting file. can drawback, if 1 in corporate office, add-ons must approved department.

 

another format/codec streaming video wmv (for windows computers, or mac's utility, such flip4mac installed), wmv allows compression without visual quality loss.

 

h.264 quite good, , more x-platform choice. again, viewer need have h.264 codec installed, becoming universal. players, apple's qt player (standard on mac, , installed free on pc) install codec. also, there several free players, vlc player , mediaplayer classic hc, contain h.264 codec, plus many more.

 

when choosing format , codec export/share, there many factors consider:

 

1. file size
2. quality desired playback
3. platform(s) file delivered
4. individual computers, on file need played
5. availability of codec viewer's computer

 

as can see, it's not quite simple, , 1 must make informed decisions, before choosing format, or codec. first two, file size , quality, think of them being on either side of balance scale. bit-rate goes higher, file size goes up, , quality. bit-rate goes down, quality, file size. since article addresses files output viewing, , not re-editing, editor can decide how far down quality, visual quality, can go, , still acceptable. choices myriad, results tied directly together.

 

for more details on codec's, see article: http://forums.adobe.com/thread/546811?tstart=0

 

for more details on output formats/codec's, see article: http://forums.adobe.com/thread/878590?tstart=0

 

remember, talking files being output viewing, , not re-editing. codec's provide visual quality @ lower bit-rates, , resulting smaller file sizes, divx/xvid, mkv, wmv, etc., not choices, if additional editing ever need done. viable options on files, re-edited, see article: http://forums.adobe.com/message/4556586#4556586

 

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