FFmpeg: How to split video efficiently?
FfmpegFfmpeg Problem Overview
I wish to split a large avi video into two smaller consecutive videos. I am using ffmpeg.
One way is to run ffmpeg two times:
ffmpeg -i input.avi -vcodec copy -acodec copy -ss 00:00:00 -t 00:30:00 output1.avi
ffmpeg -i input.avi -vcodec copy -acodec copy -ss 00:30:00 -t 00:30:00 output2.avi
But according to manpage of ffmpeg, I can make more than one ouput file from one input file using just one line:
ffmpeg -i input.avi -vcodec copy -acodec copy -ss 00:00:00 -t 00:30:00 output1.avi \
-vcodec copy -acodec copy -ss 00:30:00 -t 00:30:00 output2.avi
My question is, does the later approach save computation time and memory?
Ffmpeg Solutions
Solution 1 - Ffmpeg
The ffmpeg wiki links back to this page in reference to "How to split video efficiently". I'm not convinced this page answers that question, so I did as @AlcubierreDrive suggested…
echo "Two commands"
time ffmpeg -v quiet -y -i input.ts -vcodec copy -acodec copy -ss 00:00:00 -t 00:30:00 -sn test1.mkv
time ffmpeg -v quiet -y -i input.ts -vcodec copy -acodec copy -ss 00:30:00 -t 01:00:00 -sn test2.mkv
echo "One command"
time ffmpeg -v quiet -y -i input.ts -vcodec copy -acodec copy -ss 00:00:00 -t 00:30:00 \
-sn test3.mkv -vcodec copy -acodec copy -ss 00:30:00 -t 01:00:00 -sn test4.mkv
Which outputs...
Two commands
real 0m16.201s
user 0m1.830s
sys 0m1.301s
real 0m43.621s
user 0m4.943s
sys 0m2.908s
One command
real 0m59.410s
user 0m5.577s
sys 0m3.939s
I tested a SD & HD file, after a few runs & a little maths.
Two commands SD 0m53.94 #2 wins
One command SD 0m49.63
Two commands SD 0m55.00
One command SD 0m52.26 #1 wins
Two commands SD 0m58.60 #2 wins
One command SD 0m58.61
Two commands SD 0m54.60
One command SD 0m50.51 #1 wins
Two commands SD 0m53.94
One command SD 0m49.63 #1 wins
Two commands SD 0m55.00
One command SD 0m52.26 #1 wins
Two commands SD 0m58.71
One command SD 0m58.61 #1 wins
Two commands SD 0m54.63
One command SD 0m50.51 #1 wins
Two commands SD 1m6.67s #2 wins
One command SD 1m20.18
Two commands SD 1m7.67
One command SD 1m6.72 #1 wins
Two commands SD 1m4.92
One command SD 1m2.24 #1 wins
Two commands SD 1m1.73
One command SD 0m59.72 #1 wins
Two commands HD 4m23.20
One command HD 3m40.02 #1 wins
Two commands SD 1m1.30
One command SD 0m59.59 #1 wins
Two commands HD 3m47.89
One command HD 3m29.59 #1 wins
Two commands SD 0m59.82
One command SD 0m59.41 #1 wins
Two commands HD 3m51.18
One command HD 3m30.79 #1 wins
SD file = 1.35GB DVB transport stream
HD file = 3.14GB DVB transport stream
Conclusion
The single command is better if you are handling HD, it agrees with the manuals comments on using -ss after the input file to do a 'slow seek'. SD files have a negligible difference.
The two command version should be quicker by adding another -ss before the input file for the a 'fast seek' followed by the more accurate slow seek.
Solution 2 - Ffmpeg
Here's a useful script, it helps you split automatically: A script for splitting videos using ffmpeg
#!/bin/bash
# Written by Alexis Bezverkhyy <[email protected]> in 2011
# This is free and unencumbered software released into the public domain.
# For more information, please refer to <http://unlicense.org/>
function usage {
echo "Usage : ffsplit.sh input.file chunk-duration [output-filename-format]"
echo -e "\t - input file may be any kind of file reconginzed by ffmpeg"
echo -e "\t - chunk duration must be in seconds"
echo -e "\t - output filename format must be printf-like, for example myvideo-part-%04d.avi"
echo -e "\t - if no output filename format is given, it will be computed\
automatically from input filename"
}
IN_FILE="$1"
OUT_FILE_FORMAT="$3"
typeset -i CHUNK_LEN
CHUNK_LEN="$2"
DURATION_HMS=$(ffmpeg -i "$IN_FILE" 2>&1 | grep Duration | cut -f 4 -d ' ')
DURATION_H=$(echo "$DURATION_HMS" | cut -d ':' -f 1)
DURATION_M=$(echo "$DURATION_HMS" | cut -d ':' -f 2)
DURATION_S=$(echo "$DURATION_HMS" | cut -d ':' -f 3 | cut -d '.' -f 1)
let "DURATION = ( DURATION_H * 60 + DURATION_M ) * 60 + DURATION_S"
if [ "$DURATION" = '0' ] ; then
echo "Invalid input video"
usage
exit 1
fi
if [ "$CHUNK_LEN" = "0" ] ; then
echo "Invalid chunk size"
usage
exit 2
fi
if [ -z "$OUT_FILE_FORMAT" ] ; then
FILE_EXT=$(echo "$IN_FILE" | sed 's/^.*\.\([a-zA-Z0-9]\+\)$/\1/')
FILE_NAME=$(echo "$IN_FILE" | sed 's/^\(.*\)\.[a-zA-Z0-9]\+$/\1/')
OUT_FILE_FORMAT="${FILE_NAME}-%03d.${FILE_EXT}"
echo "Using default output file format : $OUT_FILE_FORMAT"
fi
N='1'
OFFSET='0'
let 'N_FILES = DURATION / CHUNK_LEN + 1'
while [ "$OFFSET" -lt "$DURATION" ] ; do
OUT_FILE=$(printf "$OUT_FILE_FORMAT" "$N")
echo "writing $OUT_FILE ($N/$N_FILES)..."
ffmpeg -i "$IN_FILE" -vcodec copy -acodec copy -ss "$OFFSET" -t "$CHUNK_LEN" "$OUT_FILE"
let "N = N + 1"
let "OFFSET = OFFSET + CHUNK_LEN"
done
Solution 3 - Ffmpeg
In my experience, don't use ffmpeg for splitting/join.
MP4Box, is faster and light than ffmpeg. Please tryit.
Eg if you want to split a 1400mb MP4 file into two parts a 700mb you can use the following cmdl:
MP4Box -splits 716800 input.mp4
eg for concatenating two files you can use:
MP4Box -cat file1.mp4 -cat file2.mp4 output.mp4
Or if you need split by time, use -splitx StartTime:EndTime:
MP4Box -add input.mp4 -splitx 0:15 -new split.mp4
Solution 4 - Ffmpeg
http://ffmpeg.org/trac/ffmpeg/wiki/Seeking%20with%20FFmpeg may also be useful to you. Also ffmpeg has a segment muxer that might work.
Anyway my guess is that combining them into one command would save time.
Solution 5 - Ffmpeg
> does the later approach save computation time and memory?
There is no big difference between those two examples that you provided. The first example cuts the video sequentially, in 2 steps, while the second example does it at the same time (using threads). No particular speed-up will be noticeable. You can read more about creating multiple outputs with FFmpeg
Further more, what you can use (in recent FFmpeg) is the stream segmenter muxer which can:
> output streams to a number of separate files of nearly fixed duration. Output filename pattern can be set in a fashion similar to image2.
Solution 6 - Ffmpeg
Here is a simple Windows bat file to split incoming file into 50 parts. Each part has length 1 minute. Sorry for such dumb script. I hope it is better to have a dumb windows script instead of do not have it at all. Perhaps it help someone. (Based on "bat file for loop" from this site.)
set var=0
@echo off
:start
set lz=
if %var% EQU 50 goto end
if %var% LEQ 9 set lz=0
echo part %lz%%var%
ffmpeg -ss 00:%lz%%var%:00 -t 00:01:00 -i %1 -acodec copy -vcodec copy %2_%lz%%var%.mp4
set /a var+=1
goto start
:end
echo var has reached %var%.
exit
Solution 7 - Ffmpeg
Didn't test ist, but this looks promising:
It is obviously splitting AVI into segments of same size, which implies these chunks don't loose quality or increase memory or must be recalculated.
It also uses the codec copy - does that mean it can handle very large streams ? Because this is my problem, i want to break down my avi so i could use a filter to get rid of the distorsion. But a whole avi runs for hours.
Solution 8 - Ffmpeg
Split video from:
-i - Input video file
-ss - starting time
-t - duration of split video
-c - (codec)
-c - copy (copy the codec with no changes)
ffmpeg -i input.mp4 -ss 00:00:50.0 -codec copy -t 30 output.mp4
Solution 9 - Ffmpeg
Here is a perfect way to split the video. I have done it previously, and it's working well for me.
ffmpeg -i C:\xampp\htdocs\videoCutting\movie.mp4 -ss 00:00:00 -t 00:00:05 -async 1 C:\xampp\htdocs\videoCutting\SampleVideoNew.mp4 (For cmd).
shell_exec('ffmpeg -i C:\xampp\htdocs\videoCutting\movie.mp4 -ss 00:00:00 -t 00:00:05 -async 1 C:\xampp\htdocs\videoCutting\SampleVideoNew.mp4') (for php).
Please follow this and I am sure it will work perfectly.
Solution 10 - Ffmpeg
one simple way is to use trim option with publitio url-based api.
once you get your video uploaded, just set start offset and end offset in url (so_2,eo_2) like so:
https://media.publit.io/file/so_2,eo_2/tummy.mp4
this will create instantly new videos starting from 2nd second and 2 seconds in length. you can split videos this way anyway you like.