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• Where is my ffmpeg stream getting saved to ?

  14 mars 2013, par Chris

  I'm just starting to explore ffmpeg (ultimately for use with openCV), and I'm running this command :

  root@beaglebone:/# ffmpeg -f video4linux2 -r 25 -s 640x480 -i /dev/video0 /out.avi

  At which point the camera indicator light turns on and it appears to be capturing. However when I end it with CTRL+C, the file is nowhere to be found.

  Any thoughts ?

  Full output :

  root@beaglebone:/# ffmpeg -f video4linux2 -r 25 -s 640x480 -i /dev/video0 /out.avi
  
  ffmpeg version v0.7.4, Copyright (c) 2000-2011 the Libav developers
  
    built on Oct  9 2012 10:50:57 with gcc 4.5.4 20120305 (prerelease)
  
    configuration: --enable-shared --enable-pthreads --enable-gpl --enable-postproc --enable-avfilter --cross-prefix=arm-angstrom-linux-gnueabi- --prefix=/usr --enable-ffserver --enable-ffplay --enable-x11grab --enable-libtheora --enable-libvorbis --arch=arm --target-os=linux --enable-cross-compile --extra-cflags=' -fexpensive-optimizations -fomit-frame-pointer -O4 -ffast-math -march=armv7-a -fno-tree-vectorize -mthumb-interwork -mfloat-abi=softfp -mfpu=neon -mtune=cortex-a8 --sysroot=/home/koen/setup-scripts/build/tmp-angstrom_v2012_05-eglibc/sysroots/beaglebone' --extra-ldflags='-Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed' --sysroot=/home/koen/setup-scripts/build/tmp-angstrom_v2012_05-eglibc/sysroots/beaglebone --enable-hardcoded-tables --cpu=cortex-a8
  
    libavutil    51.  7. 0 / 51.  7. 0
  
    libavcodec   53.  6. 0 / 53.  6. 0
  
    libavformat  53.  3. 0 / 53.  3. 0
  
    libavdevice  53.  0. 0 / 53.  0. 0
  
    libavfilter   2.  4. 0 /  2.  4. 0
  
    libswscale    2.  0. 0 /  2.  0. 0
  
    libpostproc  52.  0. 0 / 52.  0. 0
  
  ^C
  
  root@beaglebone:/# ls
  
  bin   dev  home  lost+found  mnt  proc  sbin  tmp  var
  
  boot  etc  lib   media       opt  run   sys   usr
  
  root@beaglebone:/#

• Adding C64 SID Music

  1er novembre 2012, par Multimedia Mike — General

  I have been working on adding support for SID files — the music format for the Commodore 64 — to the game music website for awhile. I feel a bit out of my element since I’m not that familiar with the C64. But why should I let that slow me down ? Allow me to go through the steps I have previously outlined in order to make this happen.

  
  
  

  I need to know what picture should represent the system in the search results page. The foregoing picture should be fine, but I’m getting way ahead of myself.

  Phase 1 is finding adequate player software. The most venerable contender in this arena is libsidplay, or so I first thought. It turns out that there’s libsidplay (originally hosted at Geocities, apparently, and no longer on the net) and also libsidplay2. Both are kind of old (libsidplay2 was last updated in 2004). I tried to compile libsidplay2 and the C++ didn’t agree with current version of g++.

  However, a recent effort named libsidplayfp is carrying on the SID emulation tradition. It works rather well, notwithstanding the fact that compiling the entire library has a habit of apparently hanging the Linux VM where I develop this stuff.

  Phase 2 is to develop a testbench app around the playback library. With the help of the libsidplayfp library maintainers, I accomplished this. The testbench app consistently requires about 15% of a single core of a fairly powerful Core i7. So I look forward to recommendations that I port that playback library to pure JavaScript.

  Phase 3 is plug into the web player. I haven’t worked on this yet. I’m confident that this will work since phase 2 worked (plus, I have a plan to combine phases 2 and 3).

  One interesting issue that has arisen is that proper operation of libsidplayfp requires that 3 C64 ROM files be present (the, ahem, KERNAL, BASIC interpreter, and character generator). While these are copyrighted ROMs, they are easily obtainable on the internet. The goal of my project is to eliminate as much friction as possible for enjoying these old tunes. To that end, I will just bake the ROM files directly into the player.

  Phase 4 is collecting a SID song corpus. This is the simplest part of the whole process thanks to the remarkable curation efforts of the High Voltage SID Collection (HVSC). Anyone can download a giant archive of every known SID file. So that’s a done deal.

  Or is it ? One small issue is that I was hoping that the first iteration of my game music website would focus on, well, game music. There is a lot of music in the HVSC that are original compositions or come from demos. The way that the archive is organized makes it difficult to automatically discern whether a particular SID file comes from a game or not.

  Phase 5 is munging the metadata. The good news here is that the files have the metadata built in. The not-so-great news is that there isn’t quite as much as I might like. Each file is tagged with title, author, and publisher/copyright. If there is more than one song in a file, they all have the same metadata. Fortunately, if I can import them all into my game music database, there is an opportunity to add a lot more metadata.

  Further, there is no play length metadata for these files. This means I will need to set each to a default length like 2 minutes and do something like I did before in order to automatically determine if any songs terminate sooner.

  Oddly, the issue I’m most concerned about is character encoding. This is the first project for which I’m making certain that I understand character encoding since I can’t reasonably get away with assuming that everything is ASCII. So far, based on the random sampling of SID files I have checked, there is a good chance of encountering metadata strings with characters that are not in the lower ASCII set. From what I have observed, these characters map to Unicode code points. So I finally get to learn about manipulating strings in such a way that it preserves the character encoding. At the very least, I need Python to rip the strings out of the binary SID files and make sure the Unicode remains intact while being inserted into an SQLite3 database.

• Unable to port FFmpeg C library into android

  28 avril 2016, par Navjot Bedi

  What i exactly want to-do : Access the ffmpeg.c file to modify the int main(int argc, char **argv) function to JNI and passing the command of ffmpeg as string.

  I have tried to port ffmpeg C library to android(ARM processor). I followed following different ways to do this.

  1st Try : using official ffmpeg installation documentation. Steps as follows

  a) git clone git ://source.ffmpeg.org/ffmpeg.git ffmpeg

  b) Read the INSTALL file.

  c) Download x264 library and build by using build_x264.sh which build successfully.

      NDK=/home/nav/Work/android/ndk
  
      PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt
  
      PLATFORM=$NDK/platforms/android-8/arch-arm
  
      PREFIX=/home/nav/28ffmpeg/android-ffmpeg                
  
      ./configure --prefix=$PREFIX --enable-static --enable-pic --disable-asm --disable-cli --host=arm-linux --cross-prefix=$PREBUILT/linux-x86/bin/arm-linux-androideabi- --sysroot=$PLATFORM
  
    make
  
    sudo make install
  
    sudo ldconfig

  d) Then i download ffmpeg library from (http://ffmpeg.org/releases/ffmpeg-snapshot.tar.bz2) build it by using build_android.sh

  #!/bin/bash
  
  
  
  NDK=/home/nav/Work/android/ndk
  
  PLATFORM=$NDK/platforms/android-8/arch-arm
  
  PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86
  
  PREFIX=/home/nav/28ffmpeg/android-ffmpeg
  
  
  
  function build_one
  
                  {
  
                  ./configure --target-os=linux --prefix=$PREFIX \
  
                  --enable-cross-compile \
  
                  --enable-runtime-cpudetect \
  
                  --disable-asm \
  
                  --arch=arm \
  
                  --cc=$PREBUILT/bin/arm-linux-androideabi-gcc \
  
                  --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \
  
                  --disable-stripping \
  
                  --nm=$PREBUILT/bin/arm-linux-androideabi-nm \
  
                  --sysroot=$PLATFORM \
  
                  --enable-nonfree \
  
                  --enable-version3 \
  
                  --disable-everything \
  
                  --enable-gpl \
  
                  --disable-doc \
  
                  --enable-avresample \
  
                  --enable-demuxer=rtsp \
  
                  --enable-muxer=rtsp \
  
                  --disable-ffplay \
  
                  --disable-ffserver \
  
                  --enable-ffmpeg \
  
                  --disable-ffprobe \
  
                  --enable-libx264 \
  
                  --enable-encoder=libx264 \
  
                  --enable-decoder=h264 \
  
                  --enable-protocol=rtp \
  
                  --enable-hwaccels \
  
                  --enable-zlib \
  
                  --disable-devices \
  
                  --disable-avdevice \
  
  --extra-cflags="-I/home/android-ffmpeg/include -fPIC -DANDROID -D__thumb__ -mthumb -Wfatal-errors -Wno-deprecated -mfloat-abi=softfp -mfpu=vfpv3-d16 -marm -march=armv7-a" \
  
                  --extra-ldflags="-L/home/android-ffmpeg/lib"
  
                  make -j4 install
  
  
  
  $PREBUILT/bin/arm-linux-androideabi-ar d libavcodec/libavcodec.a inverse.o
  
  $PREBUILT/bin/arm-linux-androideabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -L$PREFIX/lib  -soname libffmpeg.so -shared -nostdlib  -z,noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg.so libavcodec/libavcodec.a libavfilter/libavfilter.a libavresample/libavresample.a libavformat/libavformat.a libavutil/libavutil.a libswscale/libswscale.a -lc -lm -lz -ldl -llog -lx264 --warn-once --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/arm-linux-androideabi/4.4.3/libgcc.a
  
                  }
  
  
  
                  build_one

  e) Initially it works perfectly. But after that error comes :

  libavformat/libavformat.a(log2_tab.o):(.rodata+0x0): multiple definition of `ff_log2_tab'
  
  libavcodec/libavcodec.a(log2_tab.o):(.rodata+0x0): first defined here
  
  libavutil/libavutil.a(log2_tab.o):(.rodata+0x0): multiple definition of `ff_log2_tab'
  
  libavcodec/libavcodec.a(log2_tab.o):(.rodata+0x0): first defined here
  
  build_android.sh: 48: build_one: not found

  Result : *libffmpeg.so* not found.

  2nd Try : Then I follow steps in http://dl.dropbox.com/u/22605641/ffmpeg_android/main.html-> Builds

  a) I downloaded Pre-Build libffmpeg.so from above link.

  b) Add libffmpeg.so to libs/armeabi/ .

  c) Make Android.mk

  include $(CLEAR_VARS)
  
  LOCAL_MODULE := ffmpeg
  
  LOCAL_SRC_FILES := libffmpeg.so
  
  include $(PREBUILT_SHARED_LIBRARY)
  
  
  
  LOCAL_PATH := $(call my-dir)
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE := main
  
  LOCAL_STATIC_LIBRARIES += ffmpeg
  
  LOCAL_SRC_FILES := ffmpeg-test.c
  
  include $(BUILD_SHARED_LIBRARY)

  d) Then I do all ndk set up and all.Copy ffmpeg.c from library to ffmpeg-test.c by changing its int main function to my JNI functin and include all necessary include files.

  Error :

  Console :

    /home/nav/Work/android/ndk/ndk-build all 
  
  Prebuilt       : libffmpeg.so <= jni/
  
  Install        : libffmpeg.so => libs/armeabi/libffmpeg.so
  
  Compile thumb  : main <= ffmpeg-test.c
  
  jni/ffmpeg-test.c: In function 'print_report':
  
  jni/ffmpeg-test.c:1139:94: warning: incompatible implicit declaration of built-in function 'log2' [enabled by default]
  
  SharedLibrary  : libmain.so
  
  /home/nav/Work/android/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/main/ffmpeg-test.o: in function check_keyboard_interaction:jni/ffmpeg-test.c:2496: error: undefined reference to 'qp_hist'

  and many other undefined references.....

  Tell me where I am getting wrong. Needed Urgently.....