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• ffmpeg disconnects with different audio sample rate

  11 juillet 2017, par HRG

  Am using ffmpeg transcoder tool to convert a streaming audio input to another format.The raw audio data comes from a input device in wav format (.wmv) which can be accessed via server port (ex.8080) . The audio format is in wav with 16bits/sample and sample rate of 6000 hz.
  When I use ffmpeg to read this audio input with above specs and convert to another format it works fine.

  Ex.
  ffmpeg -f s16le -ar 6000 -ac 1 -i http://local:8080/sampleaudio.wmv -f webm out.webm

  But if i use fmmpeg to read the audio input at sample rate of 4000hz (other than the actual rate) ,it disconnects from the server always .

  Ex.
  ffmpeg -f s16le -ar 4000 -ac 1 -i http://local:8080/sampleaudio.wmv -f webm out.webm

  The error in the ffmpeg console is "Stream ends prematurely at 194604, should be 4800044"

  I know the input rate at which ffmpeg is reading and the actual audio output is different .But am curious to know

  why ffmpeg is disconnecting from the server ,what is happening behind the scene.

  Also how to enable logs for network connections(http,sockets..)

  Thanks

• ffmpeg batch convert and automator on mac - automator won't complete script

  24 février 2021, par Penarth Sounds

  Please forgive me for my lack of knowledge, i've written a short shell script for the mac in order to convert files in a folder using ffmpeg. it outputs them after conversion to a different folder, and puts the original in another folder. it all works fine in Terminal :

  


  This is the code :
&#xA;1 #! /bin/bash&#xA;2 srcExt=$1&#xA;3 destExt=$2&#xA;4&#xA;5 srcDir=$3&#xA;6 destDir=$4&#xA;7&#xA;8 opts=$5&#xA;9&#xA;10&#xA;11 for filename in "$srcDir"/<em>.$srcExt; do&#xA;12&#xA;13        basePath=${filename%.</em>}&#xA;14        baseName=${basePath##*/}&#xA;15&#xA;16        ffmpeg -i "$filename" -af loudnorm=I=-16:TP=-1.5:LRA=11 -ar 48000 -c:a libmp3lame -b:a 192k "$destDir"/"$baseName"."$destExt";&#xA;17 mv "$filename" /Users/Documents/ps_source/&#xA;18 done

  


  And this is how i run it :
./ffmpeg-ps.sh wav mp3 /Users/Documents/ps_toconvert/ /Users/Documents/ps_toconvert/ps_converted/

  


  I'm trying to use Automator to automatically run this script when a file drops into a folder. It does that ok, and sends the original to the ps_source folder, but it doesn't do the conversion or output a file to the ps_converted folder.

  


  Can anyone tell me what i'm doing wrong ? Banging my head against a wall here.

  


  Thanks heaps.

  


• how to encode videos for the web and mobile phones using ffmpeg

  3 février 2012, par Arnar Yngvason

  I'm running a website where users can upload their videos and they are all trancoded to the same format (mp4 a.t.m.). Up until now I've been using zencoder (transcoding as a service). But I want to start transcoding the videos on my own server.

  What I would like to know is :

  • Which formats should I transcode to and which sizes are needed for the videos to play on most mobile phones ?
  • Do I actually need webm ?
  • Which is better : CRF or VRF ?
  • I would like the videos to have the same bitrate/quality as the originals. Can I set a max ?
  • Is there a max bitrate I should not exceed if I want to videos to play everywhere ?

  If someone would be so kind to write down the commands I need and explain how they work and what they do, I would be very thankful :)