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• How to configure FFMPEG to generate position independent code on IOS

  8 juillet 2013, par madadi

  I am developing an app on iOS which makes use of FFMPEG for video decoding. I want to get 'position independent code' of FFMPEG working on my app. --enable-pic option in the FFMPEG configuration generates position independent code only if I set --disable-asm. I concluded this when I ran the otool on my app(otool -hv 'appname'). Below are the details :

  If I set --enable-pic alone, below is the output with otool :

  magic     cputype  cpusubtype  caps  filetype  ncmds  sizeofcmds  flags
  
  MH_MAGIC  ARM      V7          0x00  EXECUTE   29     3724        NOUNDEFS DYLDLINK TWOLEVEL WEAK_DEFINES BINDS_TO_WEAK

  If I set --enable-pic and --disable-asm below is the output with otool,

  magic     cputype  cpusubtype  caps  filetype  ncmds  sizeofcmds  flags
  
  MH_MAGIC  ARM      V7          0x00  EXECUTE   51     5520        NOUNDEFS DYLDLINK TWOLEVEL WEAK_DEFINES BINDS_TO_WEAK **PIE** 

  Below are my configuration settings for FFMPEG(build-ffmpeg-ios.sh) :

  if [  `uname` =  "Darwin" ]; then
  
    SEDCMD="sed -i '' "
  
  else
  
    SEDCMD="sed -i "
  
  fi
  
  
  
  
  
  make clean
  
  ./configure \
  
      --prefix=$PREFIX \
  
      --enable-version3 \
  
      --enable-static \
  
      --disable-shared \
  
      --disable-doc \
  
      --disable-ffmpeg \
  
      --disable-ffplay \
  
      --disable-ffprobe \
  
      --disable-ffserver \
  
      --disable-avdevice \
  
      --disable-avfilter \
  
      --disable-postproc \
  
      --enable-small \
  
      --cross-prefix="$DEVROOT/usr/bin/" \
  
      --enable-cross-compile \
  
      --target-os=darwin \
  
      --arch=$ARCH \
  
      --cpu=$CPU \
  
      --cc="$CC" \
  
      --as="$AS" \
  
      --extra-cflags="$CFLAGS" \
  
      --extra-ldflags="$CFLAGS" \
  
      --disable-symver \
  
      --disable-debug \
  
      --disable-indevs \
  
      --disable-encoders \
  
      --disable-bsfs \
  
      --enable-pic \
  
      --disable-filters \
  
      $CONFIGURE_FLAGS || exit 1;
  
  $SEDCMD 's/HAVE_INLINE_ASM 1/HAVE_INLINE_ASM 0/g' config.h
  
  make install || exit 1;

  And below is the make file I use(iOS.mk) :

  FFMPEG_LIBS := libavcodec.a libavformat.a libavutil.a libswscale.a
  
  
  
  IOS_ARMV7_FFMPEG_LIB := $(addprefix build/ios/armv7/lib/, $(FFMPEG_LIBS))
  
  
  
  IOS_UNI_FFMPEG_LIB := $(addprefix build/ios/universal/lib/, $(FFMPEG_LIBS))
  
  
  
  
  
  
  
  IPHONE_SDK_VERSION := "5.0"
  
  IPHONE_DEPLOY_SDK := "3.2"
  
  
  
  ALL_IOS_LIBS := $(IOS_UNI_FFMPEG_LIB) 
  
  
  
  build/ios/universal/lib/%.a : build/ios/armv7/lib/%.a
  
      mkdir -p build/ios/universal/lib
  
      lipo -create -output $@ $^
  
  
  
  
  
  
  
  $(IOS_ARMV7_FFMPEG_LIB): 
  
      export PREFIX="`$(ABSPATH) build/ios/armv7`" && \
  
      export ARCH="arm" && \
  
      export CPU="cortex-a8" && \
  
      export IOS_BASE_SDK="$(IPHONE_SDK_VERSION)" && \
  
      export IOS_DEPLOY_TGT="$(IPHONE_DEPLOY_SDK)" && \
  
      export CONFIGURE_FLAGS="--enable-neon" && \
  
      export PATH="`$(ABSPATH) venders`:$$PATH" && \
  
      cd venders/ffmpeg && bash ../iphone-compile.sh arm7 ../build-ffmpeg-ios.sh

  Can someone please help me with getting the FFMPEG up and running with both 'pic' and assembly optimization enabled. Without assembly optimizastion, FFMPEG would not be helpful to me as the video decoding is extremely slow.

• Why does fluent-ffmpeg only work when it throws the error Output stream closed

  29 mars 2024, par volume one

  I am using fluent-ffmpeg to process a video file (and then upload that to Amazon S3). The code is very straightforward but it only works if :

  


  

  • pipe option {end: true} is set in .output()

  


  • which has a side-effect that causes the following console log output

  


  


  


  Processing : 19.261847354642416% done Processing :
32.365144874807335% done Processing : 48.80978326261429% done Processing : 78.35771917058617%
Processing : 91.49377493455148% done Processing :
99.91264359125745% done An error occurred : Output stream closed

  


  


  Despite that error, it seems the file is generated correctly and it gets uploaded to Amazon S3 fine.

  


  This is the fluent-ffmpeg code :

  


  import {PassThrough} from 'node:stream';
import FFMpeg from 'fluent-ffmpeg';

let PassThroughStream = new PassThrough();

             FFMpeg('/testvideo.mp4')
                    .videoCodec('libx264')
                    .audioCodec('libmp3lame')
                    .size(`640x480`)
                    // Stream output requires manually specifying output formats
                    .format('mp4')
                    .outputOptions('-movflags dash')
                    .on('progress', function (progress) {
                        console.log('Processing: ' + progress.percent + '% done');
                    })
                    .on('error', function (err) {
                        console.log('An error occurred: ' + err.message);
                    })
                    .on('end', function () {
                        console.log('FFMpeg Processing finished!');
                    })
                    .output(PassThroughStream, {end: true})
                    .run();

   // Now upload to S3
    try {
          await s3Upload({
              AWSS3Client: 'mys3client',
              Bucket: 'publicbucket,
              ACL: "public-read",
              ContentType: 'video/mp4',
              Key: 'whoever/whatever.mp4',
              Body: PassThroughStream
           });
    } catch (error) {
                    console.log(`s3Upload error`, error)
                }


  


  If I set the pipe output() option to {end: false} then there is no error from fluent-ffmpeg and I get "Processing: 100% done FFMpeg Processing finished!" as the final console log.

  


  BUT the problem is that the s3Upload() does not do anything. There are no errors. Just no activity.

  


  I feel very uncomfortable letting fluent-ffmpeg end in an error even if the code itself does the job intended. It will also cause testing to fail. What could be the issue ?

  


  The command line code is : ffmpeg -i https:/xxxbucket.s3.amazonaws.com/14555/file-example.mp4 -acodec libmp3lame -vcodec libx264 -filter:v scale=w=trunc(oh*a/2)*2:h=480 -f mp4 -movflags dash pipe:1

  


• Continously running a PHP script waiting for videos to trancode

  12 mai 2017, par Ian

  I’m making a transcoding server which uses FFMPEG to convert videos to flv. After user uploads a video it’s queued for processing in amazon Simple Queue Service. System is linux ubuntu.

  Instead of running CRON each 1min I wonder if it would be possible to continously run several PHP scripts (dowload queued files, process downloaded etc). Each of them would have its own queue which would be read every 10s or so looking for new tasks.

  My question is :

  How to detect if the script is already running ? I’d run CRON each 1min and if one of the programs would not be running I’d load it again. How stuff like that is done on linux ? PID files ?

  thanks for help,
  ian