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• Soft subtitles on iPhone

  12 novembre 2012, par forthrin

  I know this question (or similar ones) has been asked all over the Web, but I still can't find a straight answer :

  1. Is it possible to mux soft subtitles into an mp4 video file (quickly, without re-encoding the video stream) that iPhone will actually display on the screen ? I have tried ffmpeg, MP4Box, Subler, Submerge and mp4v2 and none of them were successful in producing mp4 file that would display subtitles on iPhone (though some of them had subtitles when playing the video in VLC or iTunes).

  2. If iPhone does not support soft subtitles in mp4 files, then is there any command line utility (like the ones mentioned in question 1) that will render hard subtitles onto the video stream ? (I guess then this process will take hours since the video will have to be re-encoded)

  3. Finally, if there is no command line utility that can do hard subtitles, what options are there for GUI-based utilities ? Is Handbrake the best option ?

  If possible, please supply a command line example.

• how to configure ffmpeg to transplant to iphone sdk 5.1 simulator and play h264 ?

  19 décembre 2012, par user1204703

  I use lastest "ffmpeg-1.0.1" and "ffmpeg-iphone-build",to transplant fffmpeg to iphone sdk 5.1 simulator.

  and use the build-i386 script in the "ffmpeg-iphone-build" project . also I add "—enable-decoder=h264" to the "CONFIGURE_OPTIONS".

  just this :

  CONFIGURE_OPTIONS="--enable-gpl --enable-postproc --enable-swscale --enable-avfilter --disable-asm --enable-cross-compile --enable-decoder=h264"

  then execute "./build-i386".
  and I also execute below batch :

  #!/bin/tcsh -f
  
  
  
  mkdir universal
  
  
  
  mkdir lib
  
  
  
  
  
  mkdir i386
  
  
  
  
  
  mv ffmpeg-i386/libavcodec/libavcodec.a i386/
  
  
  
  mv ffmpeg-i386/libavdevice/libavdevice.a i386/
  
  
  
  mv ffmpeg-i386/libavformat/libavformat.a i386/
  
  
  
  mv ffmpeg-i386/libavutil/libavutil.a i386/
  
  
  
  mv ffmpeg-i386/libswscale/libswscale.a i386/
  
  
  
  
  
  
  
  rm universal/*.a
  
  
  
  lipo -create -arch i386 i386/libavcodec.a -output universal/libavcodec.a
  
  
  
  lipo -create -arch i386 i386/libavdevice.a -output universal/libavdevice.a
  
  
  
  lipo -create -arch i386 i386/libavformat.a -output universal/libavformat.a
  
  
  
  lipo -create -arch i386 i386/libavutil.a -output universal/libavutil.a
  
  
  
  lipo -create -arch i386 i386/libswscale.a -output universal/libswscale.a
  
  
  
  rm lib/*.a
  
  
  
  cp universal/*.a lib/

  then I use the "iFreameExtractor" demo, modify the video file to "test.h264".
  code like :

  - (void)applicationDidFinishLaunching:(UIApplication *)application {    
  
      self.video = [[VideoFrameExtractor alloc] initWithVideo:[Utilities bundlePath:@"test.h264"]];
  
  }

  then run with IPhone 5.1 Simulator.
  but, fail with error :

  [h264 @ 0x91f1800] max_analyze_duration 5000000 reached at 5019130
  
  [h264 @ 0x91f1800] Estimating duration from bitrate, this may be inaccurate
  
  [swscaler @ 0x9203600] No accelerated colorspace conversion found from yuv420p to rgb24.
  
  2012-12-19 20:19:54.419 iFrameExtractor[52708:f803] video duration: -9223372036854.775391

  I think that the reason why it can not play h264 file that when I transplant the fffmpeg to the iphone simulator, and maybe do something wrong with the configure options.
  but I do not know how to fix it.

  Can you show the correct configure or other advices ?

  Thanks for your reply ??
  I am going to crash.

• How can i save a iphone uploaded video always horizontal by ffmpeg

  24 juillet 2013, par Ranjith Reddy

  I am using FFMPEG for uploading recording video from iphone and generating frames.

  case1 : recording video in horizontal (generating video and frames in horizontal).

  case2 : recording video in vertical (generating video and frames in vertical).

  But in above 2 case i want video and frames in horizontal only.

  FFMPEG COMMAND

  %x(cd "#{tmp_path}" && ffmpeg -i "video path" -r 1 -f image2 image-%4d.jpeg )