I'm using ffmpeg to convert a
PNG image sequence into a
.mov file with alpha channel for us in my NLE.
PNG sequence was rendered out of DashWare where it was generated in sync with a 4m35s (approx) 1080p50 video clip.
As expected the image sequence consisted of just over 13,750 images.
I used the following command to convert these into the required
PNG encoded, uncompressed
ffmpeg -i imageSeq-%06d.png -vcodec png -r 50 -pix_fmt rgb32 -y video.mov
And the file converted OK but it's duration came out at 9m10s - exactly double what it should have been.
By my reckoning 4m35s at 50fps is:
((4x60)+35)x50 which is 13750 frames/images. So why did the duration double in conversion with the above command?