[FFmpeg-user] Duplicated frames warnings when processing video after pipe concatenation but not when processing source files
joelz at pobox.com
Wed Feb 21 21:15:54 EET 2018
First of all, thanks to the ffmpeg developers and community
for this awesome software.
I'm using a two-pass workflow, where I pipe concatenate
source files in the first pass, then trim and process the
result in a second pass. I am not changing framerates.
Quoting from https://video.stackexchange.com/questions/20958/ffmpeg-dropping-duplicate-frames
FFmpeg duplicates or drops frames when the input and output framerates differ.
If I apply an ffmpeg command line to process a raw MTS file
from a camera, I do not get "More than 1000 frames duplicated"
warnings during processing.
However if I combine MTS files using pipe concatenation,
ffmpeg -i concat:"./00000.MTS|./00001.MTS" -codec copy ./00000.mp4
then run the same command line on the mp4 result, I get
plentiful duplicate frame warnings.
I'm using Jon Van Sickle's statically ffmpeg, to wit, ffmpeg-git-20180216-64bit-static/ffmpeg
The command line is:
ffmpeg -i ./00000.mp4 -to 3:31 -c:v libx264 -preset:v medium -profile:v main -tune:v film -s:v 640x360 -c:a aac -b:a 80k -ac 2 -ar 24000 -level 3 -strict -2 -copyts -ss 1:29 ../final/20180220-1.mp4
The rendered video appears okay, but I would like to
understand what is occurring before running a larger
Thanks for any suggestions.
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