id	summary	reporter	owner	description	type	status	priority	component	version	resolution	keywords	cc	blockedby	blocking	reproduced	analyzed
2101	-start_number is missing documentation	norman_hendrich	llogan	"Hi guys,

I just wasted a couple of hours of my life reading broken 
ffmpeg documentation. A friend sent me a nice script
to create a time-lapse video from existing JPEGs using
ffmpeg, but it didn't work.

Documentation was a complete disaster, and error-messages
misleading. Debugging with strace finally showed what the
stupid thing was doing. Adding one line of documentation 
will fix this.



Summary of the bug:
How to reproduce:

What my friend sent me:

ffmpeg -f image2 -r 60 -i mod_image%d.jpg -r 60 -vcodec libx264 video.mp4

What I have:
Ubuntu 12.04 LTS with most recent upstream ffmpeg (0.8 something).

trial-005-camera0.jpg
trial-006-camera0.jpg
trial-007-camera0.jpg
...

this didn't work out-of-the-box. You may already suspect, why.

BUG 1:
What the online docs document: -pattern_type glob ...
This does NOT work on Ubuntu 12.04LTS. The option may have been added 
later, but it is not on the actual install. Online docs might mention 
that this option has only been added recently (if it is indeed working 
somewhere. I have my doubts this option will handle the start-index 
bug mentioned below).


BUG 2:
This particular ffmpeg version tells me that it is outdated,
and I should run avconv instead. No need to tell you, avconv
has the same options documented, but doesn't work on 12.04 either.



BUG 3:
I finally understood that foo-%d-bar.jpg was not supported.
Renaming all my files to the foo-%d.jpg pattern was easy.

Running the above script (with ""-i mod_image%d.jpg"") still tells 
me ""No such file"". Strace shows it checks 000 .. 004 and then gives
up. This is highly non-transparent to the unsuspecting user.

Please DOCUMENT that your s/f...../fine program REQUIRES the image numbering
to start with 0..4, or it will give up. Needless to say, my images
started with 005. That would add only one line in the online docs.

Another idea would be to have a ""start index"" option.
 
Probably affects all versions.


"	defect	closed	minor	documentation	git-master	worksforme					1	1