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• ffmpeg for android build - is it complete

  3 février 2015, par Robert Rowntree

  //EDIT save time and refer to the SF project . IMO, it may save a ton of work getting up to speed.....

  after more work on this issue :

  added a git project

  build is easier with custom toolchain installed so that you can invoke compiler the easy way

  sample stdout from ndk-build

  —
  originally used ubuntu 12.04 inside vmplayer on windows vista. IMO linux is better for builds than cygwin.

  I follow these instructions getting a indeterminant outcome in which the following conditions exist.

  build_android.sh seems to exit normally
  config.log has error where confirming gcc from crosstoolchain
  all the static libs are built ok
  (./libavfilter, ./libavcodec etc )
  ffmpeg.o is there and executes ok
  no ./android directory as per the prefix setting to config

  it looks like i can just push the binaries to my phone and test in a shell. If that’s ok then i can look to a jni wrapper for the static libs.

  But why didn’t the build write anything to —prefix=./android/armv7-a ??
  that path does not exist at the conclusion of the build

  Details :

  config log what was processed :

  FFMPEG_CONFIGURATION='--target-os=linux --prefix=./android/armv7-a 
  
  --enable-libvpx --enable-libvorbis --enable-pthreads --logfile=config.log
  
  --enable-cross-compile --extra-libs=-lgcc --arch=arm 
  
  --cc=/home/rob/src/android-ndk-r8/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc 
  
  --cross-prefix=/home/rob/src/android-ndk-r8/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi- 
  
  --nm=/home/rob/src/android-ndk-r8/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-nm 
  
  --sysroot=/home/rob/src/android-ndk-r8/platforms/android-14/arch-arm/ --extra-cflags='"'"' -O3 -fpic 
  
  -DANDROID -DHAVE_SYS_UIO_H=1 -Dipv6mr_interface=ipv6mr_ifindex -fasm -Wno-psabi -fno-short-enums 
  
  -fno-strict-aliasing -finline-limit=300 -mfloat-abi=softfp  -marm -march=armv7-a -mtune=cortex-a9 '"'"' 
  
  --disable-shared --enable-static --extra-ldflags='"'"'
  
  -Wl,-rpath-link=/home/rob/src/android-ndk-r8/platforms/android-14/arch-arm//usr/lib -L/home/rob/src/android-ndk-r8/platforms/android-14/arch-arm//usr/lib 
  
  -nostdlib -lc -lm -ldl -llog'"'"' 
  
  --disable-everything --enable-demuxer=mov --enable-demuxer=h264 
  
  --disable-ffplay --enable-protocol=file 
  
  --enable-avformat --enable-avcodec --enable-decoder=rawvideo 
  
  --enable-decoder=mjpeg --enable-decoder=h263 --enable-decoder=mpeg4 
  
  --enable-decoder=h264 --enable-parser=h264 --disable-network --enable-zlib --disable-avfilter --disable-avdevice'

  tail of config log contains error on compiler check

  zmbv_test='yes'
  
  zmbv_test_deps='zlib'
  
  WARNING: /home/rob/src/android-ndk-r8/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-pkg-config not found, library detection may fail.
  
  mktemp -u XXXXXX
  
  Yd2A0h
  
  WARNING: Unknown C compiler /home/rob/src/android-ndk-r8/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc, unable to select optimal CFLAGS
  
  check_ld cc
  
  check_cc
  
  BEGIN /tmp/ffconf.m9Kg3cqt.c
  
      1   int main(void){ return 0; }
  
  END /tmp/ffconf.m9Kg3cqt.c
  
  /home/rob/src/android-ndk-r8/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc -O3 -fpic -DANDROID -DHAVE_SYS_UIO_H=1 -Dipv6mr_interface=ipv6mr_ifindex -fasm -Wno-psabi -fno-short-enums -fno-strict-aliasing -finline-limit=300 -mfloat-abi=softfp -marm -march=armv7-a -mtune=cortex-a9 -c -o /tmp/ffconf.tO2EIBz5.o /tmp/ffconf.m9Kg3cqt.c
  
  ./configure: 640: ./configure: /home/rob/src/android-ndk-r8/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc: not found
  
  C compiler test failed.

  tail of build_android.sh stdout looks OK

  libavutil/opt.c: In function ‘av_find_opt’:
  
  libavutil/opt.c:41:5: warning: ‘av_next_option’ is deprecated (declared at libavutil/opt.h:347) [-Wdeprecated-declarations]
  
  CC  libavutil/pixdesc.o
  
  libavutil/opt.c: In function ‘av_opt_set_defaults’:
  
  libavutil/opt.c:601:5: warning: ‘av_opt_set_defaults2’ is deprecated (declared at libavutil/opt.h:370) [-Wdeprecated-declarations]
  
  CC  libavutil/random_seed.o
  
  CC  libavutil/rational.o
  
  CC  libavutil/rc4.o
  
  CC  libavutil/samplefmt.o
  
  CC  libavutil/sha.o
  
  CC  libavutil/timecode.o
  
  CC  libavutil/tree.o
  
  CC  libavutil/utils.o
  
  CC  libavutil/x86/cpu.o
  
  INSTALL libavdevice/avdevice.h
  
  INSTALL presets/libvpx-1080p50_60.ffpreset
  
  INSTALL presets/libvpx-1080p.ffpreset
  
  INSTALL presets/libvpx-360p.ffpreset
  
  INSTALL presets/libvpx-720p50_60.ffpreset
  
  INSTALL presets/libvpx-720p.ffpreset
  
  INSTALL presets/libx264-ipod320.ffpreset
  
  INSTALL presets/libx264-ipod640.ffpreset
  
  INSTALL doc/ffprobe.xsd
  
  INSTALL libavdevice/libavdevice.pc
  
  INSTALL libavfilter/asrc_abuffer.h
  
  INSTALL libavfilter/avcodec.h
  
  INSTALL libavfilter/avfilter.h
  
  INSTALL libavfilter/avfiltergraph.h
  
  INSTALL libavfilter/buffersink.h
  
  INSTALL libavfilter/version.h
  
  INSTALL libavfilter/vsrc_buffer.h
  
  INSTALL libavfilter/libavfilter.pc
  
  INSTALL libavformat/avformat.h
  
  INSTALL libavformat/avio.h
  
  INSTALL libavformat/version.h
  
  INSTALL libavformat/libavformat.pc
  
  INSTALL libavresample/avresample.h
  
  INSTALL libavresample/version.h
  
  INSTALL libavresample/libavresample.pc
  
  INSTALL libavcodec/avcodec.h
  
  INSTALL libavcodec/avfft.h
  
  INSTALL libavcodec/dxva2.h
  
  INSTALL libavcodec/vaapi.h
  
  INSTALL libavcodec/vda.h
  
  INSTALL libavcodec/vdpau.h
  
  INSTALL libavcodec/version.h
  
  INSTALL libavcodec/xvmc.h
  
  INSTALL libavcodec/libavcodec.pc
  
  INSTALL libswresample/libswresample.pc
  
  INSTALL libswresample/swresample.h
  
  INSTALL libswscale/swscale.h
  
  INSTALL libswscale/libswscale.pc
  
  INSTALL libavutil/adler32.h
  
  INSTALL libavutil/aes.h
  
  INSTALL libavutil/attributes.h
  
  INSTALL libavutil/audio_fifo.h
  
  INSTALL libavutil/audioconvert.h
  
  INSTALL libavutil/avassert.h
  
  INSTALL libavutil/avstring.h
  
  INSTALL libavutil/avutil.h
  
  INSTALL libavutil/base64.h
  
  INSTALL libavutil/bprint.h
  
  INSTALL libavutil/bswap.h
  
  INSTALL libavutil/common.h
  
  INSTALL libavutil/cpu.h
  
  INSTALL libavutil/crc.h
  
  INSTALL libavutil/error.h
  
  INSTALL libavutil/eval.h
  
  INSTALL libavutil/fifo.h
  
  INSTALL libavutil/file.h
  
  INSTALL libavutil/imgutils.h
  
  INSTALL libavutil/intfloat.h
  
  INSTALL libavutil/intfloat_readwrite.h
  
  INSTALL libavutil/intreadwrite.h
  
  INSTALL libavutil/lfg.h
  
  INSTALL libavutil/log.h
  
  INSTALL libavutil/lzo.h
  
  INSTALL libavutil/mathematics.h
  
  INSTALL libavutil/md5.h
  
  INSTALL libavutil/mem.h
  
  INSTALL libavutil/dict.h
  
  INSTALL libavutil/opt.h
  
  INSTALL libavutil/parseutils.h
  
  INSTALL libavutil/pixdesc.h
  
  INSTALL libavutil/pixfmt.h
  
  INSTALL libavutil/random_seed.h
  
  INSTALL libavutil/rational.h
  
  INSTALL libavutil/samplefmt.h
  
  INSTALL libavutil/sha.h
  
  INSTALL libavutil/timecode.h
  
  INSTALL libavutil/timestamp.h
  
  INSTALL libavutil/avconfig.h
  
  INSTALL libavutil/libavutil.pc
  
  AR  libavdevice/libavdevice.a
  
  AR  libavfilter/libavfilter.a
  
  AR  libavformat/libavformat.a
  
  AR  libavresample/libavresample.a
  
  AR  libavcodec/libavcodec.a
  
  AR  libswresample/libswresample.a
  
  AR  libswscale/libswscale.a
  
  AR  libavutil/libavutil.a
  
  INSTALL libavdevice/libavdevice.a
  
  INSTALL libavfilter/libavfilter.a
  
  INSTALL libavresample/libavresample.a
  
  INSTALL libswresample/libswresample.a
  
  INSTALL libswscale/libswscale.a
  
  INSTALL libavutil/libavutil.a
  
  INSTALL libavformat/libavformat.a
  
  LD  ffmpeg_g
  
  INSTALL libavcodec/libavcodec.a
  
  CP  ffmpeg
  
  STRIP   ffmpeg
  
  INSTALL install-progs-yes
  
  INSTALL ffmpeg

• Using ffmpeg (or similar) to print detailed h264 information

  26 octobre 2012, par gimmeamilk

  I have some h264 video in mpeg transport stream, and I suspect at certain points in the video it switches from 1080i/50Hz to 1080p/25Hz. I'd like to prove that using some video analysis tool. Can ffmpeg (or similar) print out such detailed decoding info ? I've tried ffmpeg setting "-loglevel debug" but it prints no more info about the actual decoding.

• YouTube's HD Video Streaming Server Technology ?

  30 septembre 2013, par bgentry

  Lately I've been researching different methods for streaming MP4s to the browser. Flash Media Server is an obvious choice here (using Cloudfront), and most solutions I've seen use the RTMP protocol.

  However, I spent some time on YouTube with Firebug and Chrome debugger figuring out how their streaming worked and I discovered some interesting differences between some of their videos and quality rates.

  My two sample videos are A and B. A is available up to 480p and B is available up to 1080p. For both videos, all rates up to 480p are served in an FLV container with H.264 video and AAC audio, over HTTP. What's interesting here is that if you have not yet downloaded (cached) the entire video, and you try to skip forward to an uncached part of the video, a new request will be made with a 'begin' parameter equal to the target offset in milliseconds. Example from Video A at 480p :

  http://v11.lscache8.c.youtube.com/videoplayback?ip=0.0.0.0&sparams=id%2Cexpire%2Cip%2Cipbits%2Citag%2Calgorithm%2Cburst%2Cfactor%2Coc%3AU0dWTldQVF9FSkNNNl9PSlhJ&fexp=904806%2C902906%2C903711&algorithm=throttle-factor&itag=35&ipbits=0&burst=40&sver=3&expire=1279756800&key=yt1&signature=D2D704D63C242CF187CAA5B5D5BAFB8DFACAC5FF.39180C01559C976717B651A7EB1D0C6249231EB7&factor=1.25&id=8568eb3135971f6f&begin=111863
  
  
  
  Response Headers:
  
  Cache-Control:public,max-age=23472
  
  Connection:close
  
  Content-Length:14320637
  
  Content-Type:video/x-flv
  
  Date:Wed, 21 Jul 2010 17:23:48 GMT
  
  Expires:Wed, 21 Jul 2010 23:55:00 GMT
  
  Last-Modified:Wed, 19 May 2010 12:31:41 GMT
  
  Server:gvs 1.0
  
  X-Content-Type-Options:nosniff

  The file returned by this URL is a fully valid FLV containing only the portion of the video after the requested offset.

  I did the same kind of test on the higher resolution versions of Video B. At 720p and 1080p, YouTube will return a video in an MP4 container, also with H.264 video and AAC audio. What's impressive to me is that their server takes the same type of offset for an MP4 video (via the 'begin' parameter) and returns a valid, streamable MP4 (moov atom at the front of the file with correct offsets) that also only includes the requested portion of the video.

  So, how does YouTube do this ? How do they generate the FLV or MP4 container on the fly with the correct headers and only the desired segment of the requested video ? I know this can be accomplished using FFMPEG to seek to the desired start point and the qt-faststart script to reposition the moov atom to the front of the stream, but it seems like this would be too slow to handle on-demand for millions of YouTube viewers.

  Ideas ?

  Thanks in advance !

  Footnote : I am not allowed to include more than 1 link at this point, so here is Video A's URL : http:// www.youtube .com/watch ?v=hWjrMTWXH28 "Video available up to 480p"