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• Decoding H.264 individual nal units

  1er juin 2015, par madprogrammer2015

  I am currently sending individual NAL units across a network. These NAL units are generated by x264. Now is it possible to feed these NAL units individually into avcodec_decode_video2 ?

  Or do I have to concatenate the nal units until they represent the same frame ? If thats the case then how is that done ?

  I have also read that I might be able to receive the SPS and PPS packets. Then wait for at least one packet, and attempt to decode. Is this correct ?

  Any advice that can be offered would be greatly appreciated

• ffplay subscription to rtmp stream fails on first try

  2 janvier 2018, par ehouse

  I have an Electron application that does some video streaming through ffmpeg. It works fine on Windows, but I am having a small problem with it on Mac. I stream the desktop with ffmpeg, and try to subscribe to the rtmp stream. I know the rtmp stream is live because I can successfully grab a frame from it.

  The problem is, when I subscribe with ffplay, it does not work, the output looks like this :
  2018/01/01 20:57:25:618 [web]     nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0

  When I subscribe again (while the previous process is still ongoing), it works : 2018/01/01 20:57:25:828 [web]  340.93 M-V:  0.001 fd=   0 aq=    0KB vq=  131KB sq=    0B f=0/0

  The only difference in output to the command line is this :

  Input #0, live_flv, from 'rtmp:{stream-url-here}':=0/0   
  
  2018/01/01 20:57:15:427 [web]   Metadata:
  
  2018/01/01 20:57:15:427 [web]     Server          : NGINX RTMP 
  
  (github.com/sergey-dryabzhinsky/nginx-rtmp-module)
  
  2018/01/01 20:57:15:427 [web]     displayWidth    : 1024
  
  2018/01/01 20:57:15:428 [web]     displayHeight   : 640
  
  2018/01/01 20:57:15:429 [web]     fps             : 20
  
  2018/01/01 20:57:15:429 [web]     profile         : 
  
  2018/01/01 20:57:15:430 [web]     level           : 
  
  2018/01/01 20:57:15:430 [web]   Duration: 00:00:00.00, start: 
  
  316.500000, bitrate: N/A
  
  2018/01/01 20:57:15:430 [web]     Stream #0:0: Video: h264 (Constrained 
  
  Baseline), yuv420p(progressive), 1024x640, 20 fps, 20 tbr, 1k tbn, 40 
  
  tbc

  I am trying to figure out why it only works on the second time subscribing, and this is the difference, which I assumes signals the it successfully received the streams info, but I am trying to figure out why it only works the second time.

  Thanks !!

• Building a shared library from static libraries for ffmpeg 2.5.2

  7 janvier 2015, par abijinx

  I am currently building a shared library for ffmpeg as myffmpeg.so using ffmpeg 0.8.6. I am achieving by combining static libs of individual modules of ffmpeg, along with a few additional static libraries. The main makefile used is as follows :

  LOCAL_PATH := $(call my-dir)
  
  
  
  include $(LOCAL_PATH)/Android_Files.mk
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE:= libavcodec
  
  LOCAL_SRC_FILES:= $(MY_AVCODEC_FILES)
  
  include $(LOCAL_PATH)/Android_Common.mk
  
  include $(BUILD_STATIC_LIBRARY)
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE:= libavfilter
  
  LOCAL_SRC_FILES:= $(MY_AVFILTER_FILES)
  
  include $(LOCAL_PATH)/Android_Common.mk
  
  include $(BUILD_STATIC_LIBRARY)
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE:= libavformat
  
  LOCAL_SRC_FILES:= $(MY_AVFORMAT_FILES)
  
  include $(LOCAL_PATH)/Android_Common.mk
  
  include $(BUILD_STATIC_LIBRARY)
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE:= libavutil
  
  LOCAL_SRC_FILES:= $(MY_AVUTIL_FILES)
  
  include $(LOCAL_PATH)/Android_Common.mk
  
  include $(BUILD_STATIC_LIBRARY)
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE:= libswscale
  
  LOCAL_SRC_FILES:= $(MY_SWSCALE_FILES)
  
  include $(LOCAL_PATH)/Android_Common.mk
  
  include $(BUILD_STATIC_LIBRARY)
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE:= ffmpeg_myc
  
  LOCAL_SRC_FILES:= ffmpeg.c cmdutils.c
  
  include $(LOCAL_PATH)/Android_Common.mk
  
  include $(BUILD_STATIC_LIBRARY)
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE := myffmpeg
  
  LOCAL_WHOLE_STATIC_LIBRARIES := libavcodec libavfilter libavformat libavutil libswscale ffmpeg_c
  
  LOCAL_LDFLAGS += -lz -lm -llog
  
  ifeq ($(FF_ENABLE_AMR),yes)
  
  LOCAL_WHOLE_STATIC_LIBRARIES += opencore-amrnb opencore-amrwb
  
  endif
  
  ifeq ($(FF_ENABLE_AAC),yes)
  
  LOCAL_WHOLE_STATIC_LIBRARIES += vo-aacenc
  
  endif
  
  
  
  include $(BUILD_SHARED_LIBRARY)

  The above makefile uses only few selected source files to get the individual static libs as mentioned in the FF_SOURCE_FILES parameter.Then combines all of those with the additional libs to create a shared library myffmpeg.so.

  Now I am trying to get a similar output with ffmpeg 2.5.2 for 64-bit arm architecture. This time I have built the latest ffmpeg using the following configure script and generated the static libraries of different ffmpeg modules like libavcodec.a, libavfilter.a, etc

  #!/bin/bash
  
  ABI=aarch64-linux-android
  
  NDK=
  
  SYSROOT=$NDK/platforms/android-21/arch-arm64/
  
  TOOLCHAIN=$NDK/toolchains/aarch64-linux-android-4.9/prebuilt/linux-x86_64
  
  CPU=arm64
  
  PREFIX=$(pwd)/android/$CPU
  
  ./configure \
  
  --prefix=$PREFIX \
  
  --cc=$TOOLCHAIN/bin/$ABI-gcc \
  
  --enable-static \
  
  --disable-doc \
  
  --disable-ffmpeg \
  
  --disable-ffplay \
  
  --disable-ffprobe \
  
  --disable-network \
  
  --disable-ffserver \
  
  --disable-devices \
  
  --disable-avdevice \
  
  --disable-swscale-alpha \
  
  --disable-doc \
  
  --disable-symver \
  
  --disable-neon \
  
  --enable-optimizations \
  
  --cross-prefix=$TOOLCHAIN/bin/aarch64-linux-android- \
  
  --target-os=linux \
  
  --arch=arm64 \
  
  --enable-cross-compile \
  
  --sysroot=$SYSROOT 
  
  
  
      --enable-libopencore-amrnb \
  
      --enable-libopencore-amrwb \
  
      --enable-libvo-aacenc \
  
      $ADDITIONAL_CONFIGURE_FLAG
  
  make clean
  
  make
  
  make install 

  Now I am trying to combine the generated static libraries i.e

  • libavcodec.a
    libavfilter.a
    libavformat.a
    libavutil.a
    libswresample.a
    libswscale.a
    with

  • ffmpeg_myc opencore-amrnb opencore-amrwb

  and generate a myffmpeg.so shared library by giving ndk-build.

  I tried to paste the generated ffmpeg static libraries from ffmpeg/android folder to obj/local/arm64-v8a (path where are all the static libs were previously created in 0.8.6 according the makefile). I also made changes to the makefile thinking that it will use the already generated ffmpeg libraries. But I found that the size of the generated shared library was too low and that it has not included the generated ffmpeg libs.

  LOCAL_PATH := $(call my-dir)
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE := myffmpeg
  
  LOCAL_WHOLE_STATIC_LIBRARIES := libavcodec libavfilter libavformat libavutil libswscale ffmpeg_c
  
  LOCAL_LDFLAGS += -lz -lm -llog
  
  ifeq ($(FF_ENABLE_AMR),yes)
  
  LOCAL_WHOLE_STATIC_LIBRARIES += opencore-amrnb opencore-amrwb
  
  endif
  
  ifeq ($(FF_ENABLE_AAC),yes)
  
  LOCAL_WHOLE_STATIC_LIBRARIES += vo-aacenc
  
  endif
  
  
  
  include $(BUILD_SHARED_LIBRARY)

  I would like to know whether I am going in a right way and have to do some minor changes. Or if I should start with an entirely different approach to achieve this. Any suggestions would be helpful.

  Thanks in advance