Creating a video file with FFMPEG using a single image (Mask)

[GoldenMeanie]

Hey folks, first off I apologize if this question is in the wrong place, but I am not sure where else to post it.

I'm creating a mask for a chromakey blend and I wanted to retain as good a quality as I can of the resulting video file, so I was going to use FFMPEG. The resulting video file has to be 7276 frames of the same image.

I have the script for making a video file from a batch of images, and it works fine. But I wanted to build a video without having to duplicate and rename 7276 frames! I tried just taking in the incremental variable from the original batch script, but it doesn't work that way. So I basically need to know of some way to tell FFMPEG to just use the same image 7276 times.

Thanks in advance for your help!

[poisondeathray]

Hey folks, first off I apologize if this question is in the wrong place, but I am not sure where else to post it.

I'm creating a mask for a chromakey blend and I wanted to retain as good a quality as I can of the resulting video file, so I was going to use FFMPEG. The resulting video file has to be 7276 frames of the same image.

I have the script for making a video file from a batch of images, and it works fine. But I wanted to build a video without having to duplicate and rename 7276 frames! I tried just taking in the incremental variable from the original batch script, but it doesn't work that way. So I basically need to know of some way to tell FFMPEG to just use the same image 7276 times.

Use -loop 1 with -t for duration (in hh:mm : ss : ms notation) and -r for fps

e.g. lets say you wanted 2 seconds of a 23.976 fps sequence derived from a single still image - this would yield 48 frames . You would have to calculate adjust the parameters for your case, according to the fps you wanted

ffmpeg -loop 1 -r 23.976 -i input.jpg -t 00:00:02 -vcodec qtrle -an output.mov

If the fps doesn't matter for your particular purpose (or you can interpret the fps in your other application), you can use 1 fps or -r 1 , the -t would be 2:01:16 for 7276 frames , because 2:01:16 is 7276 seconds, and at 1 frame per second = 7276 frames . I wouldn't use fractional fps, because it can cause problems with interpreting in other programs . You don't mention what other program you're using , but it's usually easier to import the still directly in other programs and generate the layer that way, and the filesize will be much smaller

[GoldenMeanie]

I get the same result. One frame is recorded. Here's my script...
c:\ffmpeg\ffmpeg -i c:\rawvideo\mask.bmp -loop 1 -r 29.97 -s 720x480 -aspect 4:3 -t 00:04:05 -vcodec mjpeg -vb 11261600 -an c:\rawvideo\fullmask.avi

[poisondeathray]

I get the same result. One frame is recorded. Here's my script...
c:\ffmpeg\ffmpeg -i c:\rawvideo\mask.bmp -loop 1 -r 29.97 -s 720x480 -aspect 4:3 -t 00:04:05 -vcodec mjpeg -vb 11261600 -an c:\rawvideo\fullmask.avi

are you using a relatively recent ffmpeg binary ? It works here (I didn't use -vb, but it shouldn't make a difference)

http://ffmpeg.zeranoe.com/builds/

[GoldenMeanie]

I was a build from April but installed the latest and it still gave me the same result. It still renders a file with no errors. It's just a single frame of the .bmp image, not the four minutes and five seconds I need.

[GoldenMeanie]

Okay I copied the syntax exactly as you had it but with my variables. This worked. Gonna take some tweeking. I wanted the higher bitrate in there but that might have been tripping it up. Not sure, but this does work now. Thank you!

[poisondeathray]

<deleted>

ok I see you got it working now, nevermind

[poisondeathray]

Okay I copied the syntax exactly as you had it but with my variables. This worked. Gonna take some tweeking. I wanted the higher bitrate in there but that might have been tripping it up. Not sure, but this does work now. Thank you!

It worked when I added -vb as well .

Another option is to use quantizer encoding instead of fixed with mjpeg . -v:q <some value> . Lower values yield higher quality, larger filesizes

You said you wanted "retain as good quality as I can", but note mjpeg is lossy compression, even at the lowest quantizer or highest bitrate . But lossless compression can cause the filesize to balloon (that's why most people import the still into their compositing application instead, especially since it's a static image)