[FFmpeg-user] ffmpeg - splitting, overlaying and selecting time range in multiple input/outputs with complex video filter producing empty output

Josep Carner Marsal jcm807 at nyu.edu
Tue Oct 10 17:37:46 EEST 2017


I am trying to use ffmpeg to apply multiple filters -single input, multiple outputs- . In concrete, I am splitting the output in two, then applying an overlaying patch to one of those streams, split again and select a time range. The command I am using is:

   ffmpeg \
    -i ./dataset_test/videos/jz_10_huron_barstow.mkv \
    -an \
    -sn \
    -loglevel error \
    -filter_complex \
    -map [F_0] -an -sn ./out/jz_10_huron_barstow/F/0_F.mp4\
    -map [F_1] -an -sn ./out/jz_10_huron_barstow/F/1_F.mp4\
    -map [L_0] -an -sn ./out/jz_10_huron_barstow/L/0_L.mp4\
    -map [L_1] -an -sn ./out/jz_10_huron_barstow/L/1_L.mp4\
For some reason, 0_F.mp4 is empty and 1_F.mp4 is cropped. My intuition is that it has something to do with applying splitting + overlaying + selecting. I think at some point some filter before select is changing the PTS of the frames in some way select is not properly discarding them, but I honestly don't know how to solve it. Some insights:

1) L_0 and L_1 are fine (no overlay is used in those two)

2) If I supress L outputs everything works fine (no "split" is needed at the beginning)

Could someone provide some light? I've beens stucked with this for two days and I don't really know what else to try. 

Many thanks,


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