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• IOS compile FFMpeg xcode 4.3 IOS5.1 Warning

  18 mars 2013, par user1589842

  Ld /Users/eric/Library/Developer/Xcode/DerivedData/iFrameExtractor-gqrehoaizgqylqfdiyfeasbifzbc/Build/Products/Debug-iphoneos/iFrameExtractor.app/iFrameExtractor normal armv7
  
      cd /Users/eric/Documents/iFrameExtractor
  
      setenv IPHONEOS_DEPLOYMENT_TARGET 5.1
  
      setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
  
      /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-gcc-4.2 -arch armv7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk -L/Users/eric/Library/Developer/Xcode/DerivedData/iFrameExtractor-gqrehoaizgqylqfdiyfeasbifzbc/Build/Products/Debug-iphoneos -L/Users/eric/Documents/iFrameExtractor/ffmpeg -L/Users/eric/Documents/iFrameExtractor/ffmpeg/libavcodec -L/Users/eric/Documents/iFrameExtractor/ffmpeg/libavdevice -L/Users/eric/Documents/iFrameExtractor/ffmpeg/libavformat -L/Users/eric/Documents/iFrameExtractor/ffmpeg/libavutil -L/Users/eric/Documents/iFrameExtractor/ffmpeg/libswscale -L/Users/eric/Documents/iFrameExtractor/ffmpeg/universal -L/Users/eric/Documents/iFrameExtractor/ffmpeg/lib -F/Users/eric/Library/Developer/Xcode/DerivedData/iFrameExtractor-gqrehoaizgqylqfdiyfeasbifzbc/Build/Products/Debug-iphoneos -filelist /Users/eric/Library/Developer/Xcode/DerivedData/iFrameExtractor-gqrehoaizgqylqfdiyfeasbifzbc/Build/Intermediates/iFrameExtractor.build/Debug-iphoneos/iFrameExtractor.build/Objects-normal/armv7/iFrameExtractor.LinkFileList -dead_strip -miphoneos-version-min=5.1 -lbz2.1.0 -framework Foundation -lavformat -framework CoreGraphics -framework UIKit -lavcodec -lavdevice -lavutil -lswscale -lz -o /Users/eric/Library/Developer/Xcode/DerivedData/iFrameExtractor-gqrehoaizgqylqfdiyfeasbifzbc/Build/Products/Debug-iphoneos/iFrameExtractor.app/iFrameExtractor
  
  
  
  ld: warning: ARM function not 4-byte aligned: ff_j_rev_dct_arm from /Users/eric/Documents/iFrameExtractor/ffmpeg/lib/libavcodec.a(jrevdct_arm.o)
  
  ld: warning: ARM function not 4-byte aligned: _ff_j_rev_dct_arm from /Users/eric/Documents/iFrameExtractor/ffmpeg/lib/libavcodec.a(jrevdct_arm.o)
  
  ld: warning: ARM function not 4-byte aligned: row_loop from /Users/eric/Documents/iFrameExtractor/ffmpeg/lib/libavcodec.a(jrevdct_arm.o)
  
  ld: warning: ARM function not 4-byte aligned: empty_row from /Users/eric/Documents/iFrameExtractor/ffmpeg/lib/libavcodec.a(jrevdct_arm.o)
  
  ld: warning: ARM function not 4-byte aligned: end_of_row_loop from /Users/eric/Documents/iFrameExtractor/ffmpeg/lib/libavcodec.a(jrevdct_arm.o)
  
  ld: warning: ARM function not 4-byte aligned: start_column_loop from /Users/eric/Documents/iFrameExtractor/ffmpeg/lib/libavcodec.a(jrevdct_arm.o)

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  Showing first 200 warnings only

• Write webcam video with avconv

  31 juillet 2012, par Jones

  Have problem to write video avi with avconv

  I try using

  avconv -v debug -f video4linux2 -i /dev/video1 frontal.avi

  but video not correct. I see this line [video4linux2 @ 0x8100b00] The v4l2 frame is 8160 bytes, but 614400 bytes are expected and I don't identify options to correct this.

  Output of debug

  avconv version 0.8.3-4:0.8.3-0ubuntu0.12.04.1, Copyright (c) 2000-2012 the Libav developers
  
    built on Jun 12 2012 16:37:58 with gcc 4.6.3
  
    configuration: --extra-version='4:0.8.3-0ubuntu0.12.04.1' --arch=i386 --prefix=/usr --libdir=/usr/lib/i386-linux-gnu --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --enable-runtime-cpudetect --enable-libfreetype --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i386-linux-gnu/i686/cmov --cpu=i686 --enable-shared --disable-static
  
    libavutil    51. 22. 1 / 51. 22. 1
  
    libavcodec   53. 35. 0 / 53. 35. 0
  
    libavformat  53. 21. 0 / 53. 21. 0
  
    libavdevice  53.  2. 0 / 53.  2. 0
  
    libavfilter   2. 15. 0 /  2. 15. 0
  
    libswscale    2.  1. 0 /  2.  1. 0
  
    libpostproc  52.  0. 0 / 52.  0. 0
  
  [video4linux2 @ 0x8100b00] [3]Capabilities: 4000001
  
  [video4linux2 @ 0x8100b00] Querying the device for the current frame size
  
  [video4linux2 @ 0x8100b00] Setting frame size to 640x480
  
  [video4linux2 @ 0x8100b00] The V4L2 driver set input_id: 0, input: Camera 1
  
  [video4linux2 @ 0x8100b00] The v4l2 frame is 8160 bytes, but 614400 bytes are expected
  
  [rawvideo @ 0x8102920] err{or,}_recognition separate: 1; 1
  
  [rawvideo @ 0x8102920] err{or,}_recognition combined: 1; 1
  
  [video4linux2 @ 0x8100b00] Estimating duration from bitrate, this may be inaccurate
  
  Input #0, video4linux2, from '/dev/video1':
  
    Duration: N/A, bitrate: 147456 kb/s
  
      Stream #0.0, 0, 1/1000000: Video: rawvideo, yuyv422, 640x480, 1/30, 147456 k
  
  File 'frontal.avi' already exists. Overwrite ? [y/N] y
  
  Incompatible pixel format 'yuyv422' for codec 'mpeg4', auto-selecting format 'yu
  
  [buffer @ 0x81020c0] w:640 h:480 pixfmt:yuyv422
  
  [avsink @ 0x81022a0] auto-inserting filter 'auto-inserted scaler 0' between the
  
  [scale @ 0x81026e0] w:640 h:480 fmt:yuyv422 -> w:640 h:480 fmt:yuv420p flags:0x4
  
  [mpeg4 @ 0x81019a0] err{or,}_recognition separate: 1; 1
  
  [mpeg4 @ 0x81019a0] err{or,}_recognition combined: 1; 1
  
  [mpeg4 @ 0x81019a0] detected 1 logical cores
  
  [mpeg4 @ 0x81019a0] Unsupported bit depth: 0
  
  [rawvideo @ 0x8102920] err{or,}_recognition separate: 1; 1
  
  [rawvideo @ 0x8102920] err{or,}_recognition combined: 1; 1
  
  Output #0, avi, to 'frontal.avi':
  
    Metadata:
  
      ISFT            : Lavf53.21.0
  
      Stream #0.0, 0, 1/30: Video: mpeg4, yuv420p, 640x480, 1/30, q=2-31, 200 kb/s

• How to build and link FFMPEG to iOS ?

  30 juin 2015, par Alexander Tkachenko

  all !

  I know, there are a lot of questions here about FFMPEG on iOS, but no one answer is appropriate for my case :(
  Something strange happens each case when I am trying to link FFMPEG in my project, so please, help me !

  My task is to write video-chat application for iOS, that uses RTMP-protocol for publishing and reading video-stream to/from custom Flash Media Server.

  I decided to use rtmplib, free open-source library for streaming FLV video over RTMP, as it is the only appropriate library.

  Many problem appeared when I began research of it, but later I understood how it should work.

  Now I can read live stream of FLV video(from url) and send it back to channel, with the help of my application.

  My trouble now is in sending video FROM Camera.
  Basic operations sequence, as I understood, should be the following :

  1. Using AVFoundation, with the help of sequence (Device-AVCaptureSession-AVVideoDataOutput-> AVAssetWriter) I write this to a file(If you need, I can describe this flow more detailed, but in the context of question it is not important). This flow is necessary to make hardware-accelerated conversion of live video from the camera into H.264 codec. But it is in MOV container format. (This is completed step)

  2. I read this temporary file with each sample written, and obtain the stream of bytes of video-data, (H.264 encoded, in QuickTime container). (this is allready completed step)

  3. I need to convert videodata from QuickTime container format to FLV. And it all in real-time.(packet - by - packet)

  4. If i will have the packets of video-data, contained in FLV container format, I will be able to send packets over RTMP using rtmplib.

  Now, the most complicated part for me, is step 3.

  I think, I need to use ffmpeg lib to this conversion (libavformat). I even found the source code, showing how to decode h.264 data packets from MOV file (looking in libavformat, i found that it is possible to extract this packets even from byte stream, which is more appropriate for me). And having this completed, I will need to encode packets into FLV(using ffmpeg or manually, in a way of adding FLV-headers to h.264 packets, it is not problem and is easy, if I am correct).

  FFMPEG has great documentation and is very powerfull library, and I think, there won’t be a problem to use it. BUT the problem here is that I can not got it working in iOS project.

  I have spend 3 days reading documentation, stackoverflow and googling the answer on the question "How to build FFMPEG for iOS" and I think, my PM is gonna fire me if I will spend one more week on trying to compile this library :))

  I tried to use many different build-scripts and configure files, but when I build FFMPEG, i Got libavformat, libavcodec, etc. for x86 architecture (even when I specify armv6 arch in build-script). (I use "lipo -info libavcodec.a" to show architectures)

  So I cannot build this sources, and decided to find prebuilt FFMPEG, that is build for architecture armv7, armv6, i386.

  I have downloaded iOS Comm Lib from MidnightCoders from github, and it contains example of usage FFMPEG, it contains prebuilt .a files of avcodec,avformat and another FFMPEG libraries.

  I check their architecture :

  iMac-2:MediaLibiOS root# lipo -info libavformat.a
  
  Architectures in the fat file: libavformat.a are: armv6 armv7 i386 

  And I found that it is appropriate for me !
  When I tried to add this libraries and headers to xCode project, It compiles fine(and I even have no warnings like "Library is compiled for another architecture"), and I can use structures from headers, but when I am trying to call C-function from libavformat (av_register_all()), the compiler show me error message "Symbol(s) not found for architecture armv7 : av_register_all".

  I thought, that maybe there are no symbols in lib, and tried to show them :

  root# nm -arch armv6 libavformat.a | grep av_register_all
  
  00000000 T _av_register_all

  Now I am stuck here, I don’t understand, why xCode can not see this symbols, and can not move forward.

  Please, correct me if I am wrong in the understanding of flow for publishing RTMP-stream from iOS, and help me in building and linking FFMPEG for iOS.

  I have iPhone 5.1. SDK and xCode 4.2.