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• How can I reduce the dimension/frame dimensions of a video files via command line ? Ffmpeg ?

  7 septembre 2017, par narahan

  Hi I am trying to reduce the video dimensions of some video files from 1280 x 720 to 640 x 360. I found this similar question on stackoverflow : Reducing video size with same format and reducing frame size However, the accepted answer ’ffmpeg -i -s 640x480 -b:v 512k -vcodec mpeg1video -acodec copy
  ’ is reducing my video duration from 9 seconds for example to 1 second. I’ve tried this with multiple files and they are all reducing to 1 second. Can anyone tell me why or how to fix this ?

• FFMpeg on Android, undefined references to libavcodec functions, although it is listed on command line

  1er juin 2016, par dimsuz

  I have a problem with unresolved references to ffmpeg’s libavcodec functions, so far failed to find the answer in other places (including my mind) :)

  Let me describe my setup - it takes space, but is really basic, it might be that I’m failing to see some error...

  I built an FFMPeg with ndk r5 toolchain, ffmpeg port I got from http://bambuser.com/opensource (as recommended in other questions here). It built fine, so I put several static libraries in my project like this :

  <project>/jni/bambuser_ffmpeg/libavcodec.a
  
  <project>/jni/bambuser_ffmpeg/libavformat.a
  
  <project>/jni/bambuser_ffmpeg/libavcore.a
  
  <project>/jni/bambuser_ffmpeg/libavutil.a
  
  </project></project></project></project>

  Next, I created an Android.mk in bambuser_ffmpeg folder to list these libs as a prebuilt ones :

  LOCAL_PATH := $(call my-dir)
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE := bambuser-libavcore
  
  LOCAL_SRC_FILES := libavcore.a
  
  include $(PREBUILT_STATIC_LIBRARY)
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE := bambuser-libavformat
  
  LOCAL_SRC_FILES := libavformat.a
  
  include $(PREBUILT_STATIC_LIBRARY)
  
  
  
  (same for other two libs)

  Next, I have another module which references these libs in its Android.mk, sets up include paths, etc :

  LOCAL_PATH := $(call my-dir)
  
  
  
  include $(CLEAR_VARS)
  
  
  
  LOCAL_MODULE := ffmpegtest
  
  LOCAL_STATIC_LIBRARIES := bambuser-libavcodec bambuser-libavcore bambuser-libavformat bambuser-libavutil
  
  LOCAL_SRC_FILES := ffmpeg_test.cpp
  
  LOCAL_C_INCLUDES := $(LOCAL_PATH)/../bambuser_ffmpeg/include
  
  LOCAL_LDLIBS    := -llog -lz
  
  
  
  include $(BUILD_SHARED_LIBRARY)

  And finally I have my ffmpeg_test.cpp which is really basic, like this :

  #include 
  
  
  
  extern "C" {
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  #include <libavformat></libavformat>avformat.h>
  
  }
  
  
  
  extern "C" {
  
      JNIEXPORT jint JNICALL Java_com_the7art_ffmpegtest_PaintThread_testFFMpeg(JNIEnv* env, jobject obj, jstring fileName);
  
  }
  
  
  
  JNIEXPORT jint JNICALL Java_com_the7art_ffmpegtest_PaintThread_testFFMpeg(JNIEnv* env, jobject obj, jstring fileName)
  
  {
  
      av_register_all();
  
      return 0;
  
  }

  When I run ndk-build, it compiles fine, but when linking it prints an unresolved reference to almost every function in libavcodec. Looks like only this lib’s functions are failing to be located :

  /home/dimka/src/mobile/android/ffmpegtest/obj/local/armeabi/libavformat.a(allformats.o) :
  In function

  av_register_all':
 /home/dimka/work/suzy/tmp/ffmpeg-android/ffmpeg/libavformat/allformats.c:47:
 undefined reference to
 

  avcodec_register_all’
  /home/dimka/src/mobile/android/ffmpegtest/obj/local/armeabi/libavformat.a(utils.o) :
  In function

  parse_frame_rate':
 /home/dimka/work/suzy/tmp/ffmpeg-android/ffmpeg/libavformat/utils.c:3240:
 undefined reference to
 

  av_parse_video_rate’
  /home/dimka/src/mobile/android/ffmpegtest/obj/local/armeabi/libavformat.a(utils.o) :
  In function

  parse_image_size':
 /home/dimka/work/suzy/tmp/ffmpeg-android/ffmpeg/libavformat/utils.c:3234:
 undefined reference to
 

  av_parse_video_size’
  /home/dimka/src/mobile/android/ffmpegtest/obj/local/armeabi/libavformat.a(utils.o) :
  In function

  flush_packet_queue':
 /home/dimka/work/suzy/tmp/ffmpeg-android/ffmpeg/libavformat/utils.c:1277:
 undefined reference to
 

  av_free_packet’
  /home/dimka/work/suzy/tmp/ffmpeg-android/ffmpeg/libavformat/utils.c:1283 :
  undefined reference to

  av_free_packet'
 /home/dimka/src/mobile/android/ffmpegtest/obj/local/armeabi/libavformat.a(utils.o):
 In function

  get_audio_frame_size’ :
  /home/dimka/work/suzy/tmp/ffmpeg-android/ffmpeg/libavformat/utils.c:766 :
  undefined reference to

  av_get_bits_per_sample'
 /home/dimka/src/mobile/android/ffmpegtest/obj/local/armeabi/libavformat.a(utils.o):
 In function
 

  ff_interleave_add_packet’ :
  /home/dimka/work/suzy/tmp/ffmpeg-android/ffmpeg/libavformat/utils.c:2909 :
  undefined reference to `av_dup_packet’

  and so on...

  I fail to figure why this is happening. I tried running ndk-build V=1 to check the actual linking command, and libavcodec is sitting there perfectly right, like it should. All other ffmpeg libs are there too.

  Any hints ?

• avformat/fitsenc : fill header line with spaces

  2 septembre 2017, par Paras Chadha

  avformat/fitsenc : fill header line with spaces
  Signed-off-by : Paras Chadha <paraschadha18@gmail.com>
  
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] libavformat/fitsenc.c