[FFmpeg-user] Invalid stream specifier

Radu Grigorovici radu_grigorovici at yahoo.com
Fri Dec 12 11:22:58 CET 2014

Hi all,

I'm assembling in ffmpeg frames generated by a Python script, using Inkscape, representing some geometric animations. I need to get a smoother transition between the frames, so I'm trying to generate frames at a higher rate and blend them together. I intend to generate the frames at 100 fps and blend them in successive steps to 50 fps and then to 25 fps. The problem is i get an error saying "Invalid stream specifier: fps50" and don't know how to fix it.

This is the command:

ffmpeg -r 100 -i frame_%05d.png -filter_complex [0:v]tinterlace=mode=1[even1];[0:v]tinterlace=mode=2[odd1];[even1][odd1]blend=all_mode='average'[blend1];[blend1]fps=fps=50[fps50];[fps50]tinterlace=mode=1[even2];[fps50]tinterlace=mode=2[odd2];[even2][odd2]blend=all_mode='average'[blend2];[blend2]fps=fps=25 -r 25 out_fx.mp4

and the output:

Input #0, image2, from 'frame_%05d.png':
Duration: 00:01:00.00, start: 0.000000, bitrate: N/A
Stream #0:0: Video: png, rgba, 1280x720 [SAR 3543:3543 DAR 16:9], 25 fps, 25 tbr, 25 tbn, 25 tbc
[image2 @ 0293bda0] Invalid stream specifier: fps50.
Last message repeated 1 times
Stream specifier 'fps50' in filtergraph description [0:v]tinterlace=mode=1[even1];[0:v]tinterlace=mode=2[odd1];[even1][odd1]blend=all_mode='average'[blend1];[blend1]fps=fps=50[fps50];[fps50]tinterlace=mode=1[even2];[fps50]tinterlace=mode=2[odd2];[even2][odd2]blend=all_mode='average'[blend2];[blend2]fps=fps=25 matches no streams.

The command, for blending from 50 fps to 25 fps runs ok:

ffmpeg -r 50 -i frame_%05d.png -filter_complex [0:v]tinterlace=mode=1[even];[0:v]tinterlace=mode=2[odd];[even][odd]blend=all_mode='average'[blend];[blend]fps=fps=25 -r 25 out_fx.mp4


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