Page 2 of 2
Re: Merge Videos Side-by-Side
Posted: 2013-08-18T08:19:05-07:00
by Rye
video 1 Birate: 2931 kBit/s (.avi) (1652kBit/s according to FFMPEG, rgb24 instead of yuv420p according to FFMPEG)
video 2 Bitrate: 2931 kBit/s (.avi) (1100KBit/s according to FFMPEG, rgb24 instead of yuv420p according to FFMPEG)
combined Bitrate 200 kBit/s... (.avi)
Re: Merge Videos Side-by-Side
Posted: 2013-08-18T08:26:07-07:00
by Rye
DELETE ME
Re: Merge Videos Side-by-Side
Posted: 2013-08-18T09:26:48-07:00
by snibgo
So you have doubled the number of pixels but divided the bitrate by at least ten. Other things (eg codec) being equal, that will significantly reduce quality.
Re: Merge Videos Side-by-Side
Posted: 2013-08-18T09:41:43-07:00
by Rye
By doubled you mean "put side by side ?"
What setting needs to be changed in order to get the picture nonblurry ?
Re: Merge Videos Side-by-Side
Posted: 2013-08-18T10:22:52-07:00
by snibgo
I haven't seen any of your videos, frames or commands, so can't diagnose any problems.
Each new frame contains twice as many pixels as either original. But your new video bitrate (measured in bits per second) is less than the original, by a factor of at least ten. Hence the compression (measured in bits/pixel) decreases by a factor of at least 20. Video compression is lossy, so this is almost guaranteed to reduce quality.
If you increase the bitrate, the quality may improve.
Re: Merge Videos Side-by-Side
Posted: 2013-08-18T10:35:16-07:00
by Rye
So… how do I have to change this code:
Code: Select all
ffmpeg -r 25 -b 2000 -i c%d.png combined.avi
in order to achieve higher bitrate ?
Since the pictures used right "before" the merge are crisp.
Re: Merge Videos Side-by-Side
Posted: 2013-08-18T11:13:57-07:00
by snibgo
Re-read the posts by rich2005 upthread. Also type "ffmpeg -h" for options.
Re: Merge Videos Side-by-Side
Posted: 2013-08-19T04:30:31-07:00
by Rye
Well even if I use this command (modified bitrate):
Code: Select all
ffmpeg -r 30 -b 2931 -i c%d.png test.avi
I still get a avi file with horrible quality. Not being comparable to the source stills used.
Re: Merge Videos Side-by-Side
Posted: 2013-08-20T06:49:46-07:00
by rich2005
As snibgo says there are many options that come with ffmpeg and 'avi' is just a wrapper format. Includes everything from uncompressed video thro' xvid to mp4's which unless you specify something, is what you get.
I have just popped IM into a Win7 VM and the ffmpeg that comes with it is more than adequate.
Tried a few options including motion jpeg, surprisingly that was not so good.
I would try a command line
ffmpeg -i c%d.png -r (your framerate here) -b 30k -qscale 1 combined.avi
the input -i imagefiles comes at the beginning now to allow the quality setting qscale to apply to the output. A syntax thing. The output file will be maybe 3 times larger than before but hopefully without those artifacts.