capturing at 20fps decrease file size

[cypher_soundz]

hi i have been capturing at 20 fps just to see what would happen , i use VD and select lock audio , everything seems fine , if i had done more than a test i.e a long capture say 30mins would the sound go out of sync? my source (tv pal) is 25fps , but if this works i cant see any reson except quality, to not capture at a lower frame rate. sugestions? :confused:

[Koepi]

I didn't really test it since i was wathcing some trailers which were encoded "artificially" lower-fps than the source, and the result is quite unpleasant:

if there is motion, it gets "jerky". Other than that I don't think you'll run into synch issues or get any other problems.

You may want to set your monitor refresh rate to multiples of 20 (fps) then btw, in order to prevent banding from that strange framerate.

Regards
Koepi

[^^-+I4004+-^^]

>hi i have been capturing at 20 fps just to see what would happen , i use VD and select lock audio , everything seems fine , if i had done more than a test i.e a long capture say 30mins would the sound go out of sync? my source (tv pal) is 25fps , but if this works i cant see any reson except quality, to not capture at a lower frame rate. sugestions?

you can use that for SOME materials (some slow paced sitcoms
come to my mind) but surelely not for sports or so...
benefit is that the codec will have higher "relative bitrate"
(i don't know if this term exists,but anyhow..)
ie. it's better image quality divx on 20FPS&1200kbit/s than
25FPS&1200kbit/s.....
disadvantage is jerky motion when camera moves....
i think "locked audio" is not needed as sync is kept (at least on me and win98)

lately i don't use anything lower than 25 as only that is fluent motion,and
i used lower FPS rates only on Erazor3 on some stuff that didn't needed full motion,and because that card drops frames....
(although (when i think of it) if i put it to 25 and drop or put it to 24 and not drop result is really simillar..only dropping on 25 fps is random and on 24 drops less and therefore it has constant "jerk" on motion)

if you can capture 25FPS,use it,and if you have some material that doesn't need it then you can experiment
(although i gave up on bitrate saving (as that can be regarded as one way of saving) alltogether.......)
for example if you capture tv-presenter and camera is still all the time,then 15FPS is enough,as camera doesn't move so you see no
jerking...

lowering the FPS rate is generally regarded as a poor idea,as then
you don't have original thing that was broadcasted....
(and that's true for the most of the time...)

i don't think monitor refresh rates are of any concern,as
there were no problems when i watched any framerate (15,17,19,20,23,24FPS) on any res. really....

[cypher_soundz]

Thanks for the replies , i now see it would be a bad idea unless I’m capturing the "Yule tide burning logs" channel :D lol .I might experiment just a little , it would be good if there could be a codec that have VFR (variable frame rate) could detect low motion scenes and lower frame rate and bit rate :D