Newest 'ffmpeg' Questions - Stack Overflow

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• How to combine multiple pictures into one ?

  19 octobre 2012, par zerocool

  I have four pictures,and I wanna combine them into one picture. So, I need to zoom those pictures to their original 1/4,then, combine them.

  What should I do by using the ffmpeg's swscale.

  Do you have the source code of this function?

• export a new functions in FFmpeg's dll

  19 octobre 2012, par user1677038

  i have successfully compile windows version dlls of FFmpeg using Mingw, and they can be use in my VC project.

  But now, i wanna to export one more function from avcodec-54.dll. These function is added by myself.

• Transcoding Mp4 video on Android with FFMPEG

  18 octobre 2012, par geeknizer

  I've compiled FFMPEG binary from Bambuser project (refer question) and have pushed binary and .so files to application directory.

  But when I try running FFMPEG with input file, it always complains file not found.

  1|root@android:/data/data/com.bambuser.broadcaster # ls                        
  cache           libavcodec.so   libavfilter.so  libswscale.so
  ffmpeg          libavcore.so    libavformat.so  tutorial.mp4
  lib             libavdevice.so  libavutil.so
  1|root@android:/data/data/com.bambuser.broadcaster # ./ffmpeg -i tutorial.mp4 out.mp4                                                              
  FFmpeg version UNKNOWN, Copyright (c) 2000-2010 the FFmpeg developers
    built on May  8 2012 10:11:37 with gcc 4.4.3
    configuration: --target-os=linux --cross-prefix=arm-linux-androideabi- --arch=arm --sysroot=/home/tarandeep/tools/android-ndk/platforms/android-3/arch-arm --soname-prefix=/data/data/com.bambuser.broadcaster/lib/ --enable-shared --disable-symver --enable-small --optimization-flags=-O2 --disable-everything --enable-encoder=mpeg2video --enable-encoder=nellymoser --prefix=../build/ffmpeg/armeabi-v7a --extra-cflags='-march=armv7-a -mfloat-abi=softfp' --extra-ldflags=
    libavutil     50.34. 0 / 50.34. 0
    libavcore      0.16. 0 /  0.16. 0
    libavcodec    52.99. 1 / 52.99. 1
    libavformat   52.88. 0 / 52.88. 0
    libavdevice   52. 2. 2 / 52. 2. 2
    libavfilter    1.69. 0 /  1.69. 0
    libswscale     0.12. 0 /  0.12. 0
  tutorial.mp4: No such file or directory
  

  I've tried placing file in /sdcard and other locations, I always get same output

• Hardware Accelerated h264 decoding using ffmpeg, OpenCV

  18 octobre 2012, par user1528476

  I am working on a Video analytics application where I have to decode an RTSP stream to give IplImage frames which are then fed into my analytics pipeline. Now, the OpenCV VideoCapture structure allows me to extract frames from an RTSP stream(i think it uses ffmpeg to do so) but the performance is not so great. It needs to work in real time.

  I also went ahead and wrote my own ffmpeg decoder. But just like OpenCv, performance with RTSP streams is not good. Lots of frames are dropped. However, decoding from a local file works fine.I am still working on refining the code though.

  What I need help with is this. First, can I use hardware accelerated decoding here to improve performance? My app is supposed to be cross platform, so I might need to use Directx VA(windows) and VAAPI(linux).If yes,then is there any place where I can learn how to implement hardware acceleration in code especially for ffmpeg decoding of h264?

• Using Xuggler to detect Webcam with Java

  18 octobre 2012, par Oneiros

  I'm trying to use Xuggler library to handle webcam video stream in Java.
  
  My project contains these files:
  

  • Xuggler Jar (xuggle-xuggler-5.4.jar)
  • SLF4J Jars (required by Xuggler and downloadable here):
    • jcl-over-slf4j-1.6.4.jar
    • jul-to-slf4j-1.6.4.jar
    • log4j-over-slf4j-1.6.4.jar
    • slf4j-api-1.6.4.jar
    • slf4j-ext-1.6.4.jar
    • slf4j-migrator-1.6.4.jar
    • slf4j-simple-1.6.4.jar
  • DisplayWebcamVideo.java as main class

  I run the main method using "vfwcap" and "0" as arguments.
  Application starts correctly, i can see myself from the webcam but it's just the first frame: the stream freezes and i see this output:
  
  

  5022 [Thread-3] ERROR org.ffmpeg - [vfwcap @ 000000000039A320] real-time buffer 75% full! frame dropped!

  5622 [Thread-3] ERROR org.ffmpeg - [vfwcap @ 000000000039A320] real-time buffer 85% full! frame dropped!

  6522 [Thread-3] ERROR org.ffmpeg - [vfwcap @ 000000000039A320] real-time buffer 95% full! frame dropped!

  6822 [Thread-3] ERROR org.ffmpeg - [vfwcap @ 000000000039A320] real-time buffer 101% full! frame dropped!

  6822 [Thread-3] ERROR org.ffmpeg - [vfwcap @ 000000000039A320] real-time buffer 101% full! frame dropped!
  
  
  What's the problem here? :(