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• Create and update HLS playlist programmatically

  26 février 2018, par Pierre P.

  I have a C++ application that records audio from my default input device, encodes it in AAC format and writes to a .aac file. I want to use HTTP Live Streaming to live stream this AAC file. According to this question, I have to create a FFMPEG script to split my audio file into several .ts files.

  # bitrate, width, and height, you may want to change this
  
  BR=512k
  
  WIDTH=432
  
  HEIGHT=240
  
  input=${1}
  
  
  
  # strip off the file extension
  
  output=$(echo ${input} | sed 's/\..*//' )
  
  
  
  # works for most videos
  
  ffmpeg -y -i ${input} -f mpegts -acodec libmp3lame -ar 48000 -ab 64k -s ${WIDTH}x${HEIGHT} -vcodec libx264 -b ${BR} -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -subq 7 -trellis 0 -refs 0 -coder 0 -me_range 16 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 200k -maxrate ${BR} -bufsize ${BR} -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 30 -qmax 51 -qdiff 4 -level 30 -aspect ${WIDTH}:${HEIGHT} -g 30 -async 2 ${output}-iphone.ts

  (It is slightly different in my case because I only work with audio)

  Can I do so programmatically in C++ and if so, do I have to use a third-part library or does macOS provide native functions to do so ?

• Encoding video settings with Transloadit and FFMPEG

  2 octobre 2015, par David Soler

  I’m using Transloadit to convert and compress videos from .mov to .ts format. I’m using the json templates but unfortunately the docs are not too extensive. The thing is the quality I’m getting rigth now is very poor and pixeled. If I do it through console with ffmpeg command and including some parameters as crf (Constant Rate Factor) the quality gets a lot better but I dont know how edit it in transloadit template to get the same result.

  This is the ffmpeg command I’m using to convert the video in console

  ./ffmpeg -i ../canales.mov -c:v libx264 -crf 23 -bsf:a aac_adtstoasc output.ts

  And this is the json template I’m using right now. I guess I should add parameters to ffmpeg hash but I don’t know which settings are allowed

  {
  
    "steps": {
  
      "file": {
  
        "robot": "/file/filter",
  
        "accepts": [
  
          [
  
            "${file.mime}",
  
            "regex",
  
            "video"
  
          ]
  
        ],
  
        "declines": [
  
          [
  
            "${file.size}",
  
            ">",
  
            "10485760"
  
          ],
  
          [
  
            "${file.meta.duration}",
  
            ">",
  
            "16"
  
          ]
  
        ],
  
        "error_on_decline": true
  
      },
  
      "segments": {
  
        "robot": "/video/encode",
  
        "preset": "iphone-high",
  
        "width": 1242,
  
        "height": 2208,
  
        "use": "file",
  
        "segment": true,
  
        "segment_duration": 10,
  
        "ffmpeg_stack": "v2.2.3",
  
        "ffmpeg": {
  
          "b": "1200K",
  
          "crf": 23
  
        }
  
      },
  
      "thumb": {
  
        "robot": "/video/thumbs",
  
        "use": "file",
  
        "count": 1
  
      },
  
      "store": {
  
        "robot": "/s3/store",
  
        "use": [
  
          "segments",
  
          "thumb"
  
        ],
  
        "key": "key",
  
        "secret": "Secret",
  
        "bucket": "bucket"
  
      }
  
    }
  
  }

• Building FFMPEG library for iOS6.0 ARMv7 Processor

  15 août 2013, par Jimmy

  WARNING :

  I was just informed by another user that there are some legal issues revolving around using FFMPEG for iOS, leaving the link here http://multinc.com/2009/08/24/compatibility-between-the-iphone-app-store-and-the-lgpl/

  I cleaned up my question a little bit, when I wrote it the first time I was flustered. Now I can be more clear after taking a small break.

  Edit : learned that you have to build for ARMv7, ARMv7s and iOS6.0

  I'm trying to use the FFMPEG library in an XCode 4.5.1 project. And I'm trying to build it for ARMv7. What I'm looking for is the exact process, and some explanation. I understand that this is not a well documented problem. But I know that other pople have had the same problem as me.

  What I have been able to do.

  I have been able to build the library for testing.

  1) I have been able to clone ffmpeg. For beginners this will get you started by creating a directory with the ffmpeg source. (Kudos to the guys who wrote it)

  git clone git ://source.ffmpeg.org/ffmpeg.git ffmpeg

  2) I have been able to write a config file that doesn't have any errors. We will go back to this part later. This is the command I attach to ./configure

  ./configure
  —disable-doc
  —disable-ffmpeg
  —disable-ffplay
  —disable-ffserver
  —enable-cross-compile
  —arch=arm
  —target-os=darwin
  —cc=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/llvm-gcc-4.2/bin/arm-apple-darwin10-llvm-gcc-4.2

  —as='gas-preprocessor/gas-preprocessor.pl /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/llvm-gcc-4.2/bin/arm-apple-darwin10-llvm-gcc-4.2'

  —sysroot=/applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk

  —cpu=cortex-a8
  —extra-ldflags='-arch=armv7 -isysroot /applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk'
  —enable-pic —disable-bzlib —disable-gpl —disable-shared —enable-static —disable-mmx —disable-debug —disable-neon —extra-cflags='-pipe -Os -gdwarf-2 -isysroot /applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk
  -m$thumb_opt :-no-thumb -mthumb-interwork'

  These are some things to note.

  • I had to download ( https://github.com/yuvi/gas-preprocessor ) copy the file gas-preprocessor.pl at /usr/local/bin. Set permissions to read write (777)
  • Make sure I'm using the right GCC compiler : /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/llvm-gcc-4.2/bin/arm-apple-darwin10-llvm-gcc-4.2
  • Make sure I'm using the right SDK : /applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk
  • —extra-cflags="-arch armv7" causes : error : unrecognized command line option “-arch”

  Here in lies the problem.

  I can include the library like so

  libavcodec/avcodec.h

  But when I started to write the encoder. I received this warning, and countless errors.

  ignoring file /Users/Jimmy/Development/source.ffmpeg/Library/libavutil.a, file was built for archive which is not the architecture being linked (armv7s) : /Users/Jimmy/Development/source.ffmpeg/Library/libavutil.a

  That means that I didn't build the right binary.

  What I'm looking for is someone whose done it before, to walk all of us through the process of building FFMPEG for iOS6.0 and ARMv7 and the majority of things to look out for. Thanks a ton.