[FFmpeg-user] 3 points jpeg to timelapse issue

[jb]

Hi
Having a few issues converting a jpeg sequence to adequate video. Any form of guidance appreciated.

Frontmost problem is the great loss in quality/depth (huge visible contrast increase) that occurs when applying :
	ffmpeg -f image2 -r 12 -i FILE%04d.JPG -r 12 -s 864x648 -vcodec libx264 output.mp4	(original files are ~1.1MB, 2592 x 1944 jpegs)
also tried
	ffmpeg -f image2 -r 12 -i FILE%04d.JPG -r 12 -vcodec copy output.mp4 [with previously scaled jpegs – which isn't practical at all for me…]
with same problem.

I'm on mac os 10.8.5. A Quicktime conversion (H.264 multi-pass) gives a satisfying output, no significant contrast/range/depth loss, just blurr. Yet Qt isn't practical for me
I'm sure this is documented somewhere, so forgive me for not digging further, but I can't seem to get a 2-pass with ffmpeg to work in this case.
	ffmpeg -f image2 -r 12 -i FILE%04d.JPG -pass [[1/2]] -r 12 -s 864x648 -vcodec libx264 output.mp4	???
What would the correct syntax be?
And could a 2 pass run solve my quality issue? or have I got it wrong from the start?

Secondly, once I get the settings right, I need to process the content of multiple folders in the form 101MEDIA, 102MEDIA, etc.
Any way to tell ffmpeg to do this all at once, (190GB of data, and counting…), the output being 'one' big MP4 file?

Thanks for reading and any hints.
Regards,
J