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• VBR header created for CBR encoded mp3 when using ffmpeg with lame codec ?

  7 novembre 2012, par user784637

  When I run this command to perform a lossy-to-lossy transcode from a youtube video (audio encoded in either aac or vorbis) to mp3 at constant bit rate (cbr)..

  ffmpeg -y -i input.vid -vn -acodec libmp3lame -ab 128K -- output.mp3

  the resulting file has a Xing header (intended to be associated with variable bit rate, vbr, files) instead of CBR header. I do not know if this is an issue with ffmpeg or with the lame codec. How do I force a CBR header to be written instead of the Xing Header ?

  The reason I ask is because on some old software, the song loops perpetually and on older firmware of some mp3 players the song will cause the player to crash due to the header discrepancy.

  If it's not possible to force a CBR header to written, are there any linux command line tools that can change this header ? The only linux cli program I found was mp3val, however when I run the -f option it reports the file is just fine and dandy.

• Compiling x264 for i386

  28 novembre 2012, par user293895

  How would I compile the x264 library for the i386 architecture ? Usually to force an architecture I would use the follow command :

  ./configure CC="gcc -arch i386" CXX="g++ -arch i386"

  But it doesn't seem to work for x264.

  To compile x264 I configure it and make it, this produces an x86_64 library. When I attempt to use the above command to force the i386 architecture I receive the following message :

  Unknown option CC=gcc -arch i386, ignored Unknown option CXX=g++ -arch i386, ignored

  The configure script then prints that it is configured for the X86_64 platform. I want to see it configured for the i386 platform and to produce an i386 binary.

• Recording a window and streaming it over HLS

  18 mars 2021, par Jakob Tinhofer

  I am new to ffmpeg and trying to find a way to stream a window to a website with sound using a HLS stream and video.js. I found 2 good resources :

  


  

  • This SO post describing the process of window capturing.

  


  • This web tutorial on HLS streaming from an existing video.

  


  


  I tried to just connect these 2 commands :

  


  ffmpeg -f gdigrab -framerate 30 -probesize 42M -i title="Executables" out.flv


  


  and

  


  ffmpeg -i input_vid.mp4 \
-filter_complex \
"[0:v]split=3[v1][v2][v3]; \
[v1]copy[v1out]; [v2]scale=w=1280:h=720[v2out]; [v3]scale=w=640:h=360[v3out]" \
-map [v1out] -c:v:0 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:0 5M -maxrate:v:0 5M -minrate:v:0 5M -bufsize:v:0 10M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 \
-map [v2out] -c:v:1 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:0 3M -maxrate:v:0 3M -minrate:v:0 3M -bufsize:v:0 3M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 \
-map [v3out] -c:v:2 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:0 1M -maxrate:v:0 1M -minrate:v:0 1M -bufsize:v:0 1M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 \
-map a:0 -c:a:0 aac -b:a:0 96k -ac 2 \
-map a:0 -c:a:1 aac -b:a:1 96k -ac 2 \
-map a:0 -c:a:2 aac -b:a:2 48k -ac 2 \
-f hls \
-hls_time 2 \
-hls_list_size 3\
-hls_flags independent_segments \
-hls_segment_type mpegts \
-hls_segment_filename stream_%v/data%02d.ts \
-master_pl_name master.m3u8 \
-var_stream_map "v:0,a:0 v:1,a:1 v:2,a:2" stream_%v.m3u8


  


  into this command :

  


  ffmpeg -f gdigrab -framerate 60 -probesize 42M -i title="Executables" -b:v 3M \
-filter_complex \
"[0:v]split=3[v1][v2][v3]; \
[v1]copy[v1out]; [v2]scale=w=1280:h=720[v2out]; [v3]scale=w=640:h=360[v3out]" \
-map [v1out] -c:v:0 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:0 5M -maxrate:v:0 5M -minrate:v:0 5M -bufsize:v:0 10M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 \
-map [v2out] -c:v:1 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:0 3M -maxrate:v:0 3M -minrate:v:0 3M -bufsize:v:0 3M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 \
-map [v3out] -c:v:2 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:0 1M -maxrate:v:0 1M -minrate:v:0 1M -bufsize:v:0 1M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 \
-map a:0 -c:a:0 aac -b:a:0 96k -ac 2 \
-map a:0 -c:a:1 aac -b:a:1 96k -ac 2 \
-map a:0 -c:a:2 aac -b:a:2 48k -ac 2 \
-f hls \
-hls_time 2 \
-hls_list_size 3\
-hls_flags independent_segments \
-hls_segment_type mpegts \
-hls_segment_filename stream_%v/data%02d.ts \
-master_pl_name master.m3u8 \
-var_stream_map "v:0,a:0 v:1,a:1 v:2,a:2" stream_%v.m3u8


  


  but I got these errors :

  


  [gdigrab @ 000002eb554631c0] Found window Executables, capturing 1566x694x32 at (0,0)
Input #0, gdigrab, from 'title=Executables':
  Duration: N/A, start: 1616015266.388242, bitrate: 2086689 kb/s
  Stream #0:0: Video: bmp, bgra, 1566x694, 2086689 kb/s, 60 fps, 60 tbr, 1000k tbn, 1000k tbc
Stream map 'a:0' matches no streams.
To ignore this, add a trailing '?' to the map.


  


  My first thought was that gdigrab did not record any audio, so I tried to add it :

  


  ffmpeg -thread_queue_size 128 -f gdigrab -framerate 30 -probesize 42M -i title="Spotify Premium" -f dshow -i audio="VoiceMeeter Output (VB-Audio VoiceMeeter VAIO)" \
 -b:v 3M \
-filter_complex \
"[0:v]split=3[v1][v2][v3]; \
[v1]copy[v1out]; [v2]scale=w=1280:h=720[v2out]; [v3]scale=w=640:h=360[v3out]" \
-map [v1out] -c:v:0 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:0 5M -maxrate:v:0 5M -minrate:v:0 5M -bufsize:v:0 10M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 \
-map [v2out] -c:v:1 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:0 3M -maxrate:v:0 3M -minrate:v:0 3M -bufsize:v:0 3M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 \
-map [v3out] -c:v:2 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:0 1M -maxrate:v:0 1M -minrate:v:0 1M -bufsize:v:0 1M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 \
-map a:0 -c:a:0 aac -b:a:0 96k -ac 2 \
-map a:0 -c:a:1 aac -b:a:1 96k -ac 2 \
-map a:0 -c:a:2 aac -b:a:2 48k -ac 2 \
-f hls \
-hls_time 2 \
-hls_list_size 3\
-hls_flags independent_segments \
-hls_segment_type mpegts \
-hls_segment_filename stream_%v/data%02d.ts \
-master_pl_name master.m3u8 \
-var_stream_map "v:0,a:0 v:1,a:1 v:2,a:2" stream_%v.m3u8


  


  But I still got the same error, even though that when running this to an output file it worked fine (besides dramatic fps drops but I probably should ask that in another post). I am not even sure if you can connect these commands like this. Any help would be greatly appreciated.