Video compression with Xvid codec

[limitless]

Hi I'm not sure if im posting in the right place because i just registered on this site so... please inform me if i should list the question elsewhere.

My problem is that Im trying to change the resolution of this avi file with virtualdub but in order to do that, I need to use the "Full process" mode in order to enable the filter "resize", after resizing and saved my new avi to a new file, i want to recompress the avi with xvid.

Under xvid video compression options it lets u select the desired bitrate, i've set my desired video bitrate to 169 kbps but and audio to direct stream, but after compression my video becomes 30 something kbps?

what did i do wrong?

Thanks in advance

[anonymez]

welcome to the forum http://img138.imageshack.us/img138/7017/smile6ku.gif

but after compression my video becomes 30 something kbps?

what indicates this?

[limitless]

hi thanks for the welcome, right click the avi and go to Properties it'll tell u the bit rate, I see it says 30 something kbps in the avi property yet i set my desired bitrate to 169 during the compression process ( in virtualdub, Video - Compression - xvid codec)

the reason i want to re-compress the video is because after changing the resolution, my 2 minute video with 5xx(H) by 3xx(V) resolution became 1.2 gb big, and in its properties it does not say bitrate no more, and i believe this indicates that the video is un-compressed, thus obviously i would want to compress it to contain it with a 15-20mb file.

[anonymez]

I see it says 30 something kbps in the avi property yet i set my desired bitrate to 169 during the compression process ( in virtualdub, Video - Compression - xvid codec)

that's windows media shell extension's info. i'm not sure how it calculates video bitrate, but it's incorrect. use something like mediainfo or virtualdub's file info for a more accurate value. your video is at 169kbps as you intended.

[celtic_druid]

Think you will find that the figure in properties should actually read kB since it appears to be the combined data rate in kiBytes not bits.

(169+128)*1000/1024*8=36kB

[anonymez]

just took a look, it also gives the "data rate" under the "video" headline, which most people would assume includes only video bitrate

[limitless]

Hi Celtic Druid, when i set the desired bitrate in xvid codec to 169 + original audio at 128, your formula have almost calculated the exact bitrate that was shown under the properties of the avi (properties from right clicking the avi), the actual bitrate shown was 37, but i think your formula is 100% correct !! or if i change it to (169+128)/8 = 37 exactly what i got!
however, i target for 169 kB/s *i know its BYTE now*, i changed the formula to
(X+128) / 8 = 169kB
X= 1224 kb *bits*
after reset the desired bitrate value during compression to 1224, it yield out 146kB in the avi's properties (a 23kB difference), i rechecked Xvid status after the compression (attached picture), it says Avg kbps magically became 1015 instead of the 1224 i have set. what went wrong??:evshock:
if i plug in the 1015 it indeed yield out around 146kB bitrate
(1015+128) / 8 = 143kB, but didnt i set it to 1224?

and anonymez i see only "frame rate" under video headline, no "data rate" tho

[varunb]

In order to confirm the bitrate of your avi, just open it In VirtualDub -> go to 'File' menu -> select 'File Information'. The dialog boxthat appears will show u the exact video & audio bitrate used by the avi.

[limitless]

video stream data rate "1058 kbps 0.43% overhead" lol, its still different than what i have set