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• FFMpeg generating screenshots drop frames

  6 octobre 2011, par Morgan

  I'm using FFMpeg to extract frames from a video file, and for most videos it works flawlessly. But certain videos it seems to have to seek to the position that I want to take the screenshot from, and drops all the frames on the way there taking quite a while if the position i'm generating a screenshot from is near the end of the video. Here is the command I'm using to extract my screenshot.

  ffmpeg -ss 60 -i input.mkv -vframes 1 -f image2 -an -r 1/5 output.jpg

  and the output I receive

  ffmpeg version 0.8.3, Copyright (c) 2000-2011 the FFmpeg developers
  
    built on Sep 20 2011 00:46:47 with clang 2.1 (tags/Apple/clang-163.7.1)
  
    configuration: --prefix=/Users/Morgan/Downloads/installed/ffmpeg --extra-libs=/Users/Morgan/Downloads/installed/lib/libfaac.a --enable-gpl --extra-cflags=-I/Users/Morgan/Downloads/installed/include --disable-ffplay --disable-ffserver --disable-shared --disable-debug --extra-ldflags=-L/Users/Morgan/Downloads/installed/lib --enable-libmp3lame --enable-libfaac --enable-libx264 --enable-nonfree --cc=clang
  
    libavutil    51.  9. 1 / 51.  9. 1
  
    libavcodec   53.  7. 0 / 53.  7. 0
  
    libavformat  53.  4. 0 / 53.  4. 0
  
    libavdevice  53.  1. 1 / 53.  1. 1
  
    libavfilter   2. 23. 0 /  2. 23. 0
  
    libswscale    2.  0. 0 /  2.  0. 0
  
    libpostproc  51.  2. 0 / 51.  2. 0
  
  [matroska,webm @ 0x7f9dd3007c00] Estimating duration from bitrate, this may be inaccurate
  
  
  
  Seems stream 0 codec frame rate differs from container frame rate: 47.95 (500000/10427) -> 23.98 (24000/1001)
  
  Input #0, matroska,webm, from 'input.mkv':
  
    Duration: 01:01:36.16, start: 0.000000, bitrate: 576 kb/s
  
      Stream #0.0(eng): Video: h264 (High), yuv420p, 1280x720, PAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
  
      Metadata:
  
        title           : Input Video
  
      Stream #0.1(eng): Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s (default)
  
      Metadata:
  
        title           : English Dolby Digital 5.1 AC3
  
      Stream #0.2(eng): Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
  
      Metadata:
  
        title           : Commentary
  
      Stream #0.3(eng): Subtitle: [0][0][0][0] / 0x0000 (default)
  
      Metadata:
  
        title           : English
  
  Incompatible pixel format 'yuv420p' for codec 'mjpeg', auto-selecting format 'yuvj420p'
  
  [buffer @ 0x106c10c00] w:1280 h:720 pixfmt:yuv420p tb:1/1000000 sar:1/1 sws_param:
  
  [buffersink @ 0x106c10e40] auto-inserting filter 'auto-inserted scaler 0' between the filter 'src' and the filter 'out'
  
  [scale @ 0x106c11140] w:1280 h:720 fmt:yuv420p -> w:1280 h:720 fmt:yuvj420p flags:0x4
  
  Output #0, image2, to 'output.jpg':
  
    Metadata:
  
      encoder         : Lavf53.4.0
  
      Stream #0.0(eng): Video: mjpeg, yuvj420p, 1280x720 [PAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 90k tbn, 0.20 tbc (default)
  
      Metadata:
  
        title           : Input Video
  
  Stream mapping:
  
    Stream #0.0 -> #0.0
  
  Press [q] to stop, [?] for help
  
  frame=    0 fps=  0 q=0.0 Lsize=      -0kB time=00:00:00.00 bitrate=   0.0kbits/s dup=0 drop=275    
  
  video:0kB audio:0kB global headers:0kB muxing overhead -inf%

• “Hook” libMMS to FFmpeg for iPhone Streaming

  8 novembre 2011, par Xie Xingwei

  These days, I was researching the software architechture for iPhone Streaming (Base on MMS protocol).

  As we know, in order to playback MMS audio stream, we should call libMMS to read wma stream data from remote media server, and then call FFmpeg to decode the stream data from wma format into PCM data buffer, and finally, enqueue the PCM data buffer into iPhone’s audioqueue to generate real sound.

  The introduction above just describe the working process of iPhone streaming. If we only need to implement this simple functionality, that is not difficult. Just follow the introduction above to call libMMS, FFMpeg and audioqueue step by step, we can achieve the streaming function. Actually, I have implemented the code last week.

  But, what I need is not only a simple streaming function ! I need a software architechture makes FFmpeg accessing libMMS just like accessing local filesystem !

  Does anybody know how to hook the libMMS interfaces like mms_read/mms_seek onto FFmpeg filesystem interfaces like av_read_frame/av_seek_frame ?

• Compiled file for ffmpeg - iphone audio

  3 avril 2012, par Sreekumar Kalarikkal

  I would like to build an iPhone application which streams internet radio stations which includes .wma files also. So I found that in-order to play wma files, we need FFMPEG compiled files. I tried to build FFMPEG for iPhone, but having errors. I followed the guide here,

  I can able to build ffmpeg, but when I run the project using that library, I am getting the following error.

  Ld /Users/sreekumar/Library/Developer/Xcode/DerivedData/WunderRadio-akpvnvqfzqleafaxhbibliqszxbp/Build/Intermediates/WunderRadio.build/Release-iphoneos/WunderRadio.build/Objects-normal/armv6/WunderRadio normal armv6
  
  cd "/Volumes/DISC/Radio App/Running copy/WR1.9/WunderRadio"
  
  setenv IPHONEOS_DEPLOYMENT_TARGET 3.0
  
  setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
  
  /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 -arch armv6 -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.3.sdk -L/Users/sreekumar/Library/Developer/Xcode/DerivedData/WunderRadio-akpvnvqfzqleafaxhbibliqszxbp/Build/Products/Release-iphoneos -L/Volumes/TUNEAGE/Projects/Debug-iphoneos -L/Volumes/TUNEAGE/Projects/Debug-iphonesimulator "-L/Volumes/DISC/Radio App/Running copy/WR1.9/WunderRadio/../Common/build/Release-iphonesimulator" "-L/Users/sreekumar/Downloads/WR1.9 4/Common/build/Release-iphoneos" "-L/Volumes/DISC/Radio App/Running copy/WR1.9/WunderRadio/MMS/build/MMS.build/Release-iphoneos/libmms.build/Objects-normal/armv6" "-L/Volumes/DISC/Radio App/Running copy/WR1.9/WunderRadio/MMS/build/MMS.build/Release-iphoneos/libmms.build/Objects-normal/armv7" "-L/Volumes/DISC/Radio App/Running copy/WR1.9/WunderRadio/MMS/build/Release-iphoneos" "-L/Volumes/DISC/Radio App/Running copy/WR1.9/WunderRadio/../../../Compiled frameworks MMS and ffmpeg/WR1.9/MMS/build/Release-iphoneos" "-L/Volumes/DISC/Radio App/Running copy/WR1.9/WunderRadio/../../.." "-L/Volumes/DISC/Radio App/Running copy/WR1.9/WunderRadio" -F/Users/sreekumar/Library/Developer/Xcode/DerivedData/WunderRadio-akpvnvqfzqleafaxhbibliqszxbp/Build/Products/Release-iphoneos -filelist /Users/sreekumar/Library/Developer/Xcode/DerivedData/WunderRadio-akpvnvqfzqleafaxhbibliqszxbp/Build/Intermediates/WunderRadio.build/Release-iphoneos/WunderRadio.build/Objects-normal/armv6/WunderRadio.LinkFileList -dead_strip -ObjC -Wl --allow-multiple-definition -all_load -miphoneos-version-min=3.0 -framework MessageUI -framework Foundation -framework UIKit -framework CoreGraphics -framework SystemConfiguration -framework AudioToolbox -framework QuartzCore -framework MediaPlayer -weak_framework AVFoundation -framework CoreLocation -framework CFNetwork -lffmpegLib -llibmms -lCommon -lz -o /Users/sreekumar/Library/Developer/Xcode/DerivedData/WunderRadio-akpvnvqfzqleafaxhbibliqszxbp/Build/Intermediates/WunderRadio.build/Release-iphoneos/WunderRadio.build/Objects-normal/armv6/WunderRadio
  
  
  
  ld: warning: directory not found for option '-L/Volumes/TUNEAGE/Projects/Debug-iphoneos'
  
  ld: warning: directory not found for option '-L/Volumes/TUNEAGE/Projects/Debug-iphonesimulator'
  
  ld: warning: ignoring file /Volumes/DISC/Radio App/Running copy/WR1.9/Common/build/Release-iphonesimulator/libCommon.a, file was built for archive which is not the architecture being linked (armv6)
  
  ld: duplicate symbol _fourxm_decoder in /Volumes/DISC/Radio App/libffmpegLib.a(4xm.o) and /Volumes/DISC/Radio App/libffmpegLib.a(4xm.o) for architecture armv6
  
  collect2: ld returned 1 exit status
  
  Command /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 failed with exit code 1    

  So I think anybody of you may be successfully compiled and used this. If yes please give me some instructions to do this.

  Or if you can find the solution for the error. please let me know.