Sur d’autres sites (5332)

• h264 : fix decoding multiple fields per packet with slice threads

  12 juin 2016, par Anton Khirnov

  h264 : fix decoding multiple fields per packet with slice threads
  Since we only know whether a NAL unit corresponds to a new field after
  
  parsing the slice header, this requires reorganizing the calls to slice
  
  parsing, per-slice/field/frame init and actual decoding.
  In the previous code, the function for slice header decoding also
  
  immediately started a new field/frame as necessary, so any slices
  
  already queued for decoding would no longer be decodable.
  After this patch, we first parse the slice header, and if we determine
  
  that a new field needs to be started we decode all the queued slices.
  

  • [DBH] libavcodec/h264_slice.c
  • [DBH] libavcodec/h264dec.c
  • [DBH] libavcodec/h264dec.h

• FFMPEG - Can't create a video from series of images with RGB24 pixel format

  21 juillet 2016, par DevNull

  Goal

  ---

  I’m writing a small proof-of-concept application to take some raw image data I acquire from a digital camera (a series of RGB24 images), and combine them together into a simple, no-audio, video file.

  ---

  Work So Far

  The initialization code is as follows :

  ---

  AVCodec* pCodec = NULL;
  
  AVCodecContext* pCodecContext = NULL;
  
  AVFrame* pFrame = NULL;
  
  
  
  /* Register all available codecs. */
  
  avcodec_register_all();
  
  
  
  /* Determine if desired video encoder is installed. */
  
  pCodec = avcodec_find_encoder(CODEC_ID_MJPEG);
  
  if (!pCodec) {
  
      printf("Codec not installed!\n");
  
  }
  
  
  
  pCodecContext = avcodec_alloc_context3(pCodec);
  
  pFrame = avcodec_alloc_frame();

  ---

  Very cut-and-dry. However, when I try to register the codec, it fails with my custom error message, and one dropped in a nice color-coded format directly from the FFMPEG libraries :

  ---

  [mjpeg @ 0x650d00] Specified pixel format rgb24 is invalid or not supported
  
  Codec not available.

  ---

  I can confirm that that pixel format is valid easily enough :

  ---

  Pixel formats:
  
  I.... = Supported Input  format for conversion
  
  .O... = Supported Output format for conversion
  
  ..H.. = Hardware accelerated format
  
  ...P. = Paletted format
  
  ....B = Bitstream format
  
  
  
  2>&1 ffmpeg -pix_fmts | grep -i -e rgb24 -e flags
  
  FLAGS NAME            NB_COMPONENTS BITS_PER_PIXEL
  
  IO... rgb24                  3            24

  ---

  I can also confirm that the video codec I’m trying to use is valid for encoding.

  ---

  Codecs:
  
   D..... = Decoding supported
  
   .E.... = Encoding supported
  
   ..V... = Video codec
  
   ..A... = Audio codec
  
   ..S... = Subtitle codec
  
   ...I.. = Intra frame-only codec
  
   ....L. = Lossy compression
  
   .....S = Lossless compression
  
  
  
  2>&1 ffmpeg -codecs | grep -i mjpeg              
  
   DEVIL. mjpeg                Motion JPEG

  ---

  Question

  ---

  Why is this pixel format not supported ? It seems like such a common one when working with other utilities like MATLAB, OpenCV, FreeImage, etc. Is there any set of options or functions in FFMPEG/AVcodec that can resolve this issue ? I’d like to avoid having to to manually convert my image to a different color-space if possible, so I’m not burning up CPU cycles by first converting the RGB24 image to a new format, THEN encoding a video frame with it.

  Thank you.

• Error:No such property : targetPlatform for class : com.android.build.gradle.managed.NdkConfig

  30 juillet 2016, par Alder

  I am trying to build FFMPEG into my JNI code with gradle in Android Studio. I have build FFMPEG as a .so file, in order to adapt different platform, I build it for different ABI(arm64-v8a, armeabi-v7a, mip, etc).Then I need to determine the ABI of the current build in the build.gradle file.

  Refer Experimental Plugin User Guide, my build.gradle look like this :

  apply plugin: 'com.android.model.native'    
  
  model{
  
      repositories {
  
          prebuilt(PrebuiltLibraries){
  
              ffmpeg{
  
                  headers.srcDir "src/main/jni/build/${targetPlatform.getName()}/include"
  
                  binaries.withType(SharedLibraryBinary) {
  
                      sharedLibraryFile = file("src/main/jni/build/${targetPlatform.getName()}/libvflibrary.so")
  
                  }
  
              }
  
          }
  
      }
  
      android {
  
          compileSdkVersion = 24
  
          buildToolsVersion = "23.0.3"
  
  
  
          defaultConfig {
  
              minSdkVersion.apiLevel = 15
  
              targetSdkVersion.apiLevel = 24
  
              versionCode = 1
  
              versionName = "1.0"
  
          }
  
  
  
          ndk{
  
              //platformVersion = 21
  
              moduleName = "library-jni"
  
              stl = 'gnustl_static'
  
              toolchain = "clang"
  
              abiFilters.addAll(['armeabi', 'armeabi-v7a', 'arm64-v8a', 'mips'])
  
              cppFlags.addAll(['-std=c++11', '-D__STDC_CONSTANT_MACROS'])
  
              ldLibs.addAll(['log', 'android', 'z', 'EGL', 'GLESv2'])
  
          }
  
  
  
          sources {
  
              main {
  
                  jni {
  
                      source{
  
                          srcDirs 'src/main/jni'
  
                      }
  
                      dependencies {
  
                          library 'ffmpeg' linkage 'shared'
  
                      }
  
                  }
  
              }
  
          }
  
      }
  
  }

  I am getting an error :

  Error:No such property : targetPlatform for class :
  com.android.build.gradle.managed.NdkConfig.

  Does anyone have an idea on how I can solve this, please ?