Recherche avancée

Sur d’autres sites (4523)

• ffmpeg inconsistent speed results by version breaking large audio file into multiple pieces with -ss/-to positional parameters [closed]

  2 novembre 2024, par BenH

  I am trying to chop a large (12 hour+) audio file up into multiple segments using multiple -ss/-to positional operations.

  


  ffmpeg.exe -loglevel error -stats -i "C:\data\chapters\joined_output.mp3" -ss -1 -to 1159 -c copy "C:\data\chapters\001 - Chapter 1.mp3" -ss 1159 -to 1800 -c copy "C:\data\chapters\002 - Chapter 2.mp3" -ss 1800 -to 3181 -c copy "C:\data\chapters\003 - Chapter 3.mp3" ... output.mp3


  


  The '...' indicates that I have more than 20 of such repeated statements to break up into 20 or more chapter files.

  


  I arrived on this because using individual command were processing the entire file each time to parse out the section I wanted. I realize there is an option to place -ss/-to prior to the input file, and have since discovered that this appears to work quicker, but I have not found syntax to use this in a single command and therefore must create a separate command for each chapter.

  


  The above syntax appears to work fine, but was taking about 4 minutes to process. When I reverted to older versions this operation completes much quicker. About 20 seconds with version 6.1 and about 10 seconds on version 5.

  


  There is some discrepancy with how the old versions report the length of the file (it appears to show only about 6.5 hours processed in "out_time" value), but the resulting output files appear to be correct. I think it might be reporting out_time of only the longest section it is processing as the 6.5 hours appear to match the length of that output section.

  


  To be clear, version 5 using my above syntax appears to create all my output files correctly in 10 seconds.

  


  If I split them up into individual commands with -ss/-to before the input, then it actually takes longer with ffmpeg version 5/6 (about 45 seconds compared to 10-20 seconds).
With the latest version 7 it takes about 1 min, 15 secs. Much better than the 4 minutes using my syntax above but still well slower than using version 5/6 with that same syntax.

  


  So, in short, why am I able to (apparently) properly split this 12 hour file into about 25 different segments in about 10 seconds using the syntax above on version 5, but it takes 2x that long on 6, and 30x that long on 7 ? I assume there are just syntax changes I can't figure out or some changes to default behavior ?

  


• Fffmpeg drawtext filter creating large output file size and taking high cpu ?

  9 juillet 2019, par theburningfire

  I have a video input file on which i am drawing a user porvided text on it. I am able to draw text on video file using drawtext filter of ffmpeg and it works file, but main issue arises with ffmpeg command.

  That is when i run my ffmpeg command then three things happens :-
  1. The output video file size is larger then input file size.
  2. The output video file loses quality of video than input video file.
  3. The cpu is going very high.

  The ffmpeg command that is am using is-

  ffmpeg -i input1.asf -vf drawtext="fontfile=/path/to/font.ttf: \text='Stack Overflow': fontcolor=white: fontsize=24: box=1: boxcolor=black@0.5: \boxborderw=5: x=10: y=10" -codec:a copy IndVsNZ.asf

  for avoiding video quality lose i had use this parameter "-c:v libx264 -crf 20".

  what is am trying to achieve is that i can drawtext on my video file without losing quality,same output file size as input file and low cpu(because it hangs my system).

  I have tried various solutions on internet but cant found problem to this. If any link related to this please share. i am new to ffmpeg.

  Thankyou !

• Is the output ts file size when using ffmpeg convert rtmp to hls with adaptive bitrate too large ?

  21 juillet 2022, par bui the vuong

  I want to convert rtmp to hls that supports adaptive bitrate , when referencing in many sources I use this configuration , but I found the ts file size of 240 to 720 bitrates is larger than I thought , I thought src will have to be the maximum size or 720p , please explain to me why , and is it possible to reduce the file size ( does any option in ffmpeg increase it ) ? Thanks everyone.

  


  My ffmpeg command :

  


  ffmpeg -i rtmp://localhost:1935/$app/$name -async 1 -vsync -1
                    -c:v libx264 -c:a aac -b:v 256k -b:a 64k -g 2 -vf "scale=426:trunc(ow/a/2)*2" -tune zerolatency -preset ultrafast -crf 23 -f flv rtmp://localhost:1935/show/$name_240
                    -c:v libx264 -c:a aac -b:v 768k -b:a 128k -g 2 -vf "scale=720:trunc(ow/a/2)*2" -tune zerolatency -preset ultrafast -crf 23 -f flv rtmp://localhost:1935/show/$name_360
                    -c:v libx264 -c:a aac -b:v 1024k -b:a 128k -g 2 -vf "scale=960:trunc(ow/a/2)*2" -tune zerolatency -preset ultrafast -crf 23 -f flv rtmp://localhost:1935/show/$name_480
                    -c:v libx264 -c:a aac -b:v 1920k -b:a 128k -g 2 -vf "scale=1280:trunc(ow/a/2)*2" -tune zerolatency -preset ultrafast -crf 23 -f flv rtmp://localhost:1935/show/$name_720
                    -c copy -f flv rtmp://localhost:1935/show/$name_src;