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• CPU spike when transitioning from a still image

  21 avril 2016, par lagnat

  After streaming a still image (with x264) for a long period of time, the transition to live video makes the CPU spike to 100% for a period of time proportionally equal to how long the still image was streaming. More specifically, transitioning after a minute will result in a CPU spike lasting about 15 seconds. Transitioning after 30 minutes will result in that spike lasting closer to 3 minutes.

  Does this symptom make any sense and is there anything I can do about it?

• Why sliced thread affect so much on realtime encoding using ffmpeg x264 ?

  13 avril 2016, par CurtisGuo

  I'm using ffmpeg libx264 to encode a 720p screen captured from x11 in realtime with a fps of 30. when I use -tune zerolatency paramenter, the average encode time per-frame can be as large as 12ms with profile baseline.

  After a study of the ffmpeg x264 source code, I found that the key parameter leading to such long encode time is sliced-threads which enabled by -tune zerolatency. After disabled using -x264-params sliced-threads=0 the encode time can be as low as 2ms

  And with sliced-threads disabled, the CPU usage will be 40%, while only 20% when enabled.

  Can someone explain the details about this sliced-thread? Especially in realtime encoding(assume no frame is buffered to be encoded. only encode when a frame is captured).

• How to encode H.264 video using FFmpeg C API and then open the output with a media player ?

  4 avril 2016, par GummiB

  I'm trying to encode a H.264 video with the FFMPEG C API. I have successfully compiled and executed the decoding/encoding example provided by FFMPEG.

  The problem I'm facing is that the .mpg file (encoded with AV_CODEC_ID_MPEG1VIDEO) the example creates works. Windows creates a thumbnail and everything. On the other hand the .h264 (encoded with AV_CODEC_ID_H264) file does not. When I try to play the file in VLC the play/pause button just flickers, no thumbnail in windows, no nothing.

  During encoding libx264 reports the following:

  [libx264 @ 004b81a0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  [libx264 @ 004b81a0] profile High, level 1.3
  [libx264 @ 004b81a0] frame I:3     Avg QP:26.79  size:  2116
  [libx264 @ 004b81a0] frame P:12    Avg QP:26.60  size:   789
  [libx264 @ 004b81a0] frame B:10    Avg QP:31.39  size:   499
  [libx264 @ 004b81a0] consecutive B-frames: 20.0% 80.0%
  [libx264 @ 004b81a0] mb I  I16..4: 78.3% 11.6% 10.1%
  [libx264 @ 004b81a0] mb P  I16..4: 77.4%  0.6%  0.1%  P16..4: 20.3%  0.7%  0.9%  0.0%  0.0%    skip: 0.0%
  [libx264 @ 004b81a0] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  9.4%  0.2%  0.0%  direct:11.0%  skip:79.4%  L0:25.4% L1:35.4% BI:39.2%
  [libx264 @ 004b81a0] final ratefactor: 17.03
  [libx264 @ 004b81a0] 8x8 transform intra:3.4% inter:31.3%
  [libx264 @ 004b81a0] direct mvs  spatial:0.0% temporal:100.0%
  [libx264 @ 004b81a0] coded y,uvDC,uvAC intra: 4.4% 35.8% 1.6% inter: 1.3% 34.5% 9.5%
  [libx264 @ 004b81a0] i16 v,h,dc,p:  0%  0%  0% 100%
  [libx264 @ 004b81a0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  7% 20% 17% 49%  0%  0%  0%  1%  6%
  [libx264 @ 004b81a0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 14%  7% 18% 45%  2%  7%  2%  3%  2%
  [libx264 @ 004b81a0] i8c dc,h,v,p:  2%  6%  4% 88%
  [libx264 @ 004b81a0] Weighted P-Frames: Y:0.0% UV:0.0%
  [libx264 @ 004b81a0] ref P L0: 95.6%  1.6%  2.2%  0.5%  0.2%
  [libx264 @ 004b81a0] ref B L0: 67.5% 28.5%  3.2%  0.8%
  [libx264 @ 004b81a0] kb/s:166.45
  

  "ffprobe.exe test.h264 -show_streams" returns

  [STREAM]
  index=0
  codec_name=h264
  codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
  profile=High
  codec_type=video
  codec_time_base=1/50
  codec_tag_string=[0][0][0][0]
  codec_tag=0x0000
  width=352
  height=288
  has_b_frames=1
  sample_aspect_ratio=0:1
  display_aspect_ratio=0:1
  pix_fmt=yuv420p
  level=13
  timecode=N/A
  id=N/A
  r_frame_rate=50/2
  avg_frame_rate=25/1
  time_base=1/1200000
  start_pts=N/A
  start_time=N/A
  duration_ts=N/A
  duration=N/A
  bit_rate=N/A
  nb_frames=N/A
  nb_read_frames=N/A
  nb_read_packets=N/A
  DISPOSITION:default=0
  DISPOSITION:dub=0
  DISPOSITION:original=0
  DISPOSITION:comment=0
  DISPOSITION:lyrics=0
  DISPOSITION:karaoke=0
  DISPOSITION:forced=0
  DISPOSITION:hearing_impaired=0
  DISPOSITION:visual_impaired=0
  DISPOSITION:clean_effects=0
  DISPOSITION:attached_pic=0
  [/STREAM]
  

  There you can see:

  start_time=N/A
  duration_ts=N/A
  duration=N/A
  

  I have tried countless changes to the AVCodecContext and multitude of parameters options to av_opt_set function. Still no luck getting a working H.264 video. I have even tried different builds of FFmpeg. No luck.

  I'm using the "FFmpeg git-0fb64da 32-bit Dev" build from Zeranoe and MinGw 4.7.2

• Q.For encoding error of ffmpeg

  21 mars 2016, par 社畜根性

  I ran the following command.

  ffmpeg -i test.mp4 -threads 2 -codec:v libx264 -s:v 1280x720 -aspect:v 16:9 -b:v 256k -map 0 -f segment -segment_format mpegts -segment_time 10 -segment_list stream.m3u8 streamfiles/stream%03d.ts
  

  Execution result

  ffmpeg version N-75926-gce0834b Copyright (c) 2000-2015 the FFmpeg developers
    built with gcc 4.6 (Debian 4.6.3-14+rpi1)
    configuration: --arch=armel --target-os=linux --enable-shared --enable-gpl --enable-libx264 --enable-nonfree
    libavutil      55.  3.100 / 55.  3.100
    libavcodec     57.  5.100 / 57.  5.100
    libavformat    57.  3.100 / 57.  3.100
    libavdevice    57.  0.100 / 57.  0.100
    libavfilter     6. 11.100 /  6. 11.100
    libswscale      4.  0.100 /  4.  0.100
    libswresample   2.  0.100 /  2.  0.100
    libpostproc    54.  0.100 / 54.  0.100
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf56.40.100
    Duration: 00:00:03.28, start: 0.000000, bitrate: 10159 kb/s
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080, 10156 kb/s, 25 fps, 25 tbr, 1200k tbn, 2400k tbc (default)
      Metadata:
        handler_name    : VideoHandler
  Illegal instruction
  

  The result is that an error occurred. Someone told me that it's an error if you do not put the option to ./configure of libx264. That option is the --extra-cflags='-march=armv6' --extra-ldflags='-march=armv6'. Otherwise it would use the instruction of unsupported.

  So I ran ./configure with the option, then I ran the make and now I'm getting an error message:

  common/arm/quant-a.S: Assembler messages:
  common/arm/quant-a.S:362: Error: selected processor does not support ARM mode `rbit r1,r1'
  common/arm/quant-a.S:363: Error: selected processor does not support ARM mode `rbit r1,r1'
  Makefile:217: recipe for target 'common/arm/quant-a.o' failed
  make: *** [common/arm/quant-a.o] Error 1
  

  I do not know the meaning of this error. How should you deal me this error?

  I use the machine is Raspberry PI B+ and my OS is Raspbian. I want to use ffmpeg and libx264.

  Any advice and suggestions will be greatly appreciated.

• Compiling FFmpeg : libx264 not found

  17 mars 2016, par SaidTagnit

  I hope some one helps me the solve this problems. I was trying to compile FFmpeg 2.2.3 library under ubuntu 12.04LTS for android using android ndk r10e by following this tutorials:

  Tutorial1

  Tutorial2

  here is my build_android.sh file:

  #!/bin/bash
  NDK=/home/rango/Desktop/android-ndk-r10e
  SYSROOT=$NDK/platforms/android-19/arch-arm/
  TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86
  
  #ADDI_LDFLAGS="-L /usr/local/lib"
  #ADDI_CFLAGS="-I /usr/include"
  
  function build_one
  {
  ./configure \
  --prefix=$PREFIX \
  --enable-shared \
  --enable-static \
  --disable-doc \
  --disable-ffmpeg \
  --disable-ffplay \
  --disable-ffprobe \
  --disable-ffserver \
  --disable-doc \
  --disable-symver \
  --enable-protocol=concat \
  --enable-protocol=file \
  --enable-muxer=mp4 \
  --enable-demuxer=mpegts \
  --enable-memalign-hack \
  --enable-gpl \
  --enable-libx264 \
  --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
  --target-os=linux \
  --arch=arm \
  --enable-cross-compile \
  --sysroot=$SYSROOT \
  --extra-cflags="-Os -fpic -marm $ADDI_CFLAGS" \
  --extra-ldflags="$ADDI_LDFLAGS" \
  
  make clean
  make -j4
  make install
  }
  
  CPU=arm
  PREFIX=$(pwd)/android/$CPU
  
  build_one
  

  when i execute buid_android.sh script without --enable-libx264 \ line everything is going well and i can get .a files on android/arm/ folder. but with this line it fails and show the following error in the console:

  ERROR: libx264 not found

  If you think configure made a mistake, make sure you are using the latest version from Git. If the latest version fails, report the problem to the ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net. Include the log file "config.log" produced by configure as this will help

  it seems like it can't find where the libraries are, as i get a lot of the following errors in config.log file:

  "LIBNAME".h: No such file or directory newlib.h: No such file or directory mingw.h: No such file or directory x264.h: No such file or directory

  Here is the tail of config.log file:

  check_mathfunc truncf 1
  check_ld cc
  check_cc
  BEGIN /tmp/ffconf.zGKqGin6.c
      1   #include 
      2   float foo(float f, float g) { return truncf(f); }
      3   int main(void){ return (int) foo; }
  END /tmp/ffconf.zGKqGin6.c
  /home/rango/Desktop/android-ndk-r10e/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc --sysroot=/home/rango/Desktop/android-ndk-r10e/platforms/android-19/arch-arm/ -isysroot /home/rango/Desktop/android-ndk-r10e/platforms/android-19/arch-arm/ -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Dstrtod=avpriv_strtod -DPIC -Os -fpic -marm -march=armv5te -std=c99 -fomit-frame-pointer -fPIC -marm -pthread -c -o /tmp/ffconf.8Q9ke3aO.o /tmp/ffconf.zGKqGin6.c
  /home/rango/Desktop/android-ndk-r10e/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc --sysroot=/home/rango/Desktop/android-ndk-r10e/platforms/android-19/arch-arm/ -isysroot /home/rango/Desktop/android-ndk-r10e/platforms/android-19/arch-arm/ -Wl,--as-needed -o /tmp/ffconf.3sjTkc5z /tmp/ffconf.8Q9ke3aO.o -lm -lz -pthread
  check_lib x264.h x264_encoder_encode -lx264
  check_header x264.h
  check_cpp
  BEGIN /tmp/ffconf.zGKqGin6.c
      1   #include 
      2   int x;
  END /tmp/ffconf.zGKqGin6.c
  /home/rango/Desktop/android-ndk-r10e/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc --sysroot=/home/rango/Desktop/android-ndk-r10e/platforms/android-19/arch-arm/ -isysroot /home/rango/Desktop/android-ndk-r10e/platforms/android-19/arch-arm/ -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Dstrtod=avpriv_strtod -DPIC -Os -fpic -marm -march=armv5te -std=c99 -fomit-frame-pointer -fPIC -marm -pthread -E -o /tmp/ffconf.8Q9ke3aO.o /tmp/ffconf.zGKqGin6.c
  /tmp/ffconf.zGKqGin6.c:1:18: fatal error: x264.h: No such file or directory
   #include 
                    ^
  compilation terminated.
  ERROR: libx264 not found