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• Does anyone find this useful ? - Compiling FFMPEG on Windows with Cywin and NDK r5 [closed]

  5 avril 2017, par protectedmember

  Does anyone find this information useful in anyway ?

  I’ve been trying to compile this thing for a while now and I know of the numerous posts floating around the internet offering help. I have read and tried most of the suggestions and wanted to colate my success into this single post for others to benefit from.

  Since I don’t have a blog, I thought it wouldn’t hurt to post on here instead.

  I have managed to compile FFMPEG 0.10.3 (Freedom) on Windows 7 (32 bit) using NDK r5 and Cygwin. The steps :

  1 - Download/install Cygwin in the root of your C drive. I’m not going to give instructions on this, it’s simple enough and there are plenty of tutorials on this.

  2 - Download NDK r5 from here and extract to the root of your C drive.

  3 - Download FFMPEG 0.10.3 from here and extract to the root of your C drive.

  4 - Open the file ’configure’ in the root of the FFMPEG directory in a text editor.

  5 - Comment out lines 2073, 2074 and 2075.

  6 - Below 2075, add the following line :

  TMPDIR=c :/cygwin/tmp

  7 - Download this script (thankyou roman10) and place it inside your FFMPEG root directory. Rename the file to

  build_android.sh

  8 - Open the script in a text editor and edit line 17 to read

  c :/android-ndk-r5

  9 - Click start > run and type "bash" (without the speech marks) and press enter.

  10 - Type the following and press enter :

  cd /cygdrive/c/ffmpeg-0.10.3

  11 - Type the following and press enter :

  dos2unix build_andoird.sh

  12 - Type the following and press enter :

  ./build_android.sh

  13 - Sit back and wait... libffmpeg.so will soon appear in your "c :\ffmpeg-0.10.3\android\" directory (where is defined in the bottom of the script from roman10’s blog). The default architecture is armv7-a.

  The script from roman10’s blog will actually compile quite a large shared object (.so) file. The compiler flags can be adjusted to suit your needs in the script from roman10’s blog.

• FFMPEG multi-channel conversion (dts -> ac3) reverts to 2 channel when also adding AAC stereo stream. Why ?

  12 avril 2020, par JTC

  Assume the origin file contains 2 streams, one HD video and other DTS-MA multi-channel audio. The following produces a functioning .mkv with copied video and 5.1 AC3 soundtrack. The -map statements are optional in this case.

  



  ffmmpeg -i input.mkv -map 0:0 -map 0:1 -c:v copy -c:a:0 ac3 -ac 6 output.mkv


  



  Now add the aac stereo downmix stream...

  



  ffmmpeg -i input.mkv -map 0:0 -map 0:1 -map 0:1 -c:v copy -c:a:0 ac3 -ac 6 -c:a:1 aac -ac 2 -b:a:1 256k output.mkv


  



  This outputs the two audio streams, but both are two-channel stereo. Omitting the downmix "-ac 2" argument restores 6 channels to both audio streams, but this isn't what I want. The final downmix specifier seems to be controlling both codecs. Is this a bug, or is there a commandline error ?

  


• ffmpeg broken pipeline error when push stream to rtmp server

  18 janvier 2024, par tsang

  enter image description here

  


  I was trying to push stream to a rtmp server. firstly, I use obs,it works ok. then I decide to use ffmpeg to do it. below is the command I use.

  


  ./ffmpeg -re -stream_loop -1 -i input.mp4 \
 -vcodec libx264 \
 -r 60 \
 -b:v 10000k\
 -vf scale=1920*1080\
 -c:a aac\
 -b:a 160k -ar 48000 -ac 2\
 -f flv\
 -flvflags no_duration_filesize\
 -chunk_size 4096\
 rtmp://txy2.live-push.bilivideo.com/live-bvc/?streamname=live_423756438_27609488&key=***************&schedule=rtmp&pflag=1
  #rtmp://192.168.3.2:1935/live/test


  


  all the options above refer from the network packages catched by wireshark when push video with obs as the screenshot shows below.
enter image description here

  


  I've already tried my best. help needed.