[FFmpeg-user] ffmpeg cutting movies into multiple parts

blubee blubeeme gurenchan at gmail.com
Mon Jun 6 09:26:59 CEST 2016


Hi

Thanks for the reply but It seemed like I was just going about things all
wrong with my last attempt at the script. I totally rewrote the whole thing
from scratch using ffprobe to get the length and cut the video up into a
max of 10 minute chunks but also handle the cases where if the video was
less than 10 minutes long it would stop instead of just writing out junk
data.

Here's the code, there's probably excess variable declarations and stuff
but I can clean that up later, I am just glad that the whole program works
as expected on linux systems.

#!/bin/bash
DIR="/../../../*" #directory where the movie files are located
OUT_DIR="/../../../../" #directory where the processed movie files will be
exported
OUTPUT_FILE=""

file_duration_flat=0
file_duration_int=0
working_file_duration=0
default_chunk_size=600 #video length in seconds (10 minutes)
chunk_size=600 #video length in seconds (10 minutes)
video_pieces=0
video_pieces_hum_re=0
video_pieces_hum_re_cnt=0
counter=0
chunk_start_time=0
chunk_end_time=0
tt=10
end=10
iteration=0

#extract simple metadata from files
for f in $DIR
do
echo $f
file_duration_float=$(ffprobe -i "$f" -show_format -v quiet | sed -n
's/duration=//p')
file_duration_int=$( echo "($file_duration_float+0.5)/1" | bc )
working_file_duration_int=$file_duration_int
working_file_duration=$(expr $file_duration_int - $chunk_size )
echo $file_duration_int

#---------------------------------------------
# get the count of pieces to cut the file into
#---------------------------------------------
# echo $working_file_duration_int
while [ "$working_file_duration_int" -ge "$chunk_size" ]
do
working_file_duration_int=$(($working_file_duration_int - chunk_size))
video_pieces=$((video_pieces + 1 ))
video_pieces_hum_re=$((video_pieces + 1 ))
video_pieces_hum_re_cnt=$video_pieces_hum_re

# echo "cut video into $video_pieces pieces"
# echo "cut video into human readable $video_pieces_hum_re pieces"
# echo "cut video human readable c $video_pieces_hum_re_cnt pieces"
done
#---------------------------------------------

#---------------------------------------------
# determine the start and end time of each clip
#---------------------------------------------
while [ $working_file_duration_int -gt -1 ]
do
filename=$(basename "$f")
input_file="$filename"
filename=${filename::-4}" "
file_extension=${f: -3}
input_file_dir=$(dirname "$f")"/"


if [ $iteration -eq 0 ]
then
working_file_duration_int=$((file_duration_int - chunk_size))
chunk_start_time=$(($iteration * $chunk_size))
chunk_end_time=$(($chunk_start_time + $chunk_size))

echo "iteration $iteration video length left $working_file_duration_int
start time: $chunk_start_time end time: $chunk_end_time"

OUTPUT_FILE="$OUT_DIR$filename$iteration.mkv"
$(ffmpeg -hide_banner -loglevel panic -i "$f" -ss $chunk_start_time -t
$chunk_end_time [you're desired encoding] "$OUTPUT_FILE")
iteration=$((iteration+1))
fi
if [ $working_file_duration_int -le $chunk_size ]
then
# echo "break early because time is $working_file_duration_int"
chunk_size=$working_file_duration_int
working_file_duration_int=$((working_file_duration_int - chunk_size))
chunk_start_time=$chunk_end_time
chunk_end_time=$(($chunk_start_time + $chunk_size))

echo "early chunk size: $chunk_size iteration $iteration video length left
$working_file_duration_int start: $chunk_start_time end: $chunk_end_time"

OUTPUT_FILE="$OUT_DIR$filename$iteration.mkv"
$(ffmpeg -hide_banner -loglevel panic -i "$f" -ss $chunk_start_time -t
$chunk_end_time [you're desired encoding] "$OUTPUT_FILE")
iteration=0
chunk_size=$default_chunk_size
break
else
chunk_start_time=$chunk_end_time
chunk_end_time=$(($chunk_start_time + $chunk_size))
working_file_duration_int=$((working_file_duration_int - chunk_size))
echo "iteration $iteration video length left $working_file_duration_int
start: $chunk_start_time end: $chunk_end_time"

OUTPUT_FILE="$OUT_DIR$filename$iteration.mkv"
$(ffmpeg -hide_banner -loglevel panic -i "$f" -ss $chunk_start_time -t
$chunk_end_time [you're desired encoding] "$OUTPUT_FILE")
iteration=$((iteration+1))
fi
done
done

I've thrown a few different file types at this and it works, even with
blank spaces in the name. I've left out my fffmpeg function because that's
specific to the user. It could be as simple as just a straight copy or a
total re-encode.

On Sun, Jun 5, 2016 at 11:39 PM, Moritz Barsnick <barsnick at gmx.net> wrote:

> On Sun, Jun 05, 2016 at 11:56:52 +0800, blubee blubeeme wrote:
> > The line above "$OUT_DIR" doesn't work and throws a cryptic error.
>
> It may be cryptic to you, but if it comes from ffmpeg, it most likely
> has a meaning. And it's one of the two things you didn't tell us. ;-)
>
> More precisely: Please post the full command line (unscripted) and the
> complete, uncut console output.
>
> When running a bash script, you can dump the actually used command line
> by running with "bash -x".
>
> Moritz
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