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• Adding a image resource over video file from sd card using ffmpeg or MediaMuxer for android

  18 septembre 2014, par Alin

  I am stuck in this area which I am not comfortable at all to work in.

  Here is what I did so far :

  • Made an Ubuntu VirtualBox machine
  • Downloaded latest ffmpeg version which is 2.3.3
  • Compiled ffmpeg to be compatible with armv7-a so in the end I get two folders : include and lib. In include I have the headers and in libs the *.so files (just as in http://www.roman10.net/how-to-build-ffmpeg-with-ndk-r9/)

  

  I have created a new android project and made a jni folder and this is how far I went... Even this, with all the struggle being new to linux and compiling took me almost a week to reach.

  Adding a watermark in ffmpeg I believe it is done on libavfilter ? I have to dig on this matter, however the original ffmpeg I need to translate into my project is :

  ffmpeg -i input.avi -i logo.png -filter_complex 'overlay=10:main_h-overlay_h-10' output.avi

  As far as I am studying now I need to do inside jni :

  • create a add_watermark.c file in which I need to somehow call the function that does the filter overlay call

  • create Android.mk to load this and the ffmpeg needed libraries

    LOCAL_PATH := $(call my-dir)

    include $(CLEAR_VARS)

    LOCAL_MODULE := add-watermark

    LOCAL_SRC_FILES := add-watermark.c

    LOCAL_LDLIBS := -llog -ljnigraphics -lz

    LOCAL_SHARED_LIBRARIES := libavformat libavcodec libswscale libavutil

    include $(BUILD_SHARED_LIBRARY)

    $(call import-module,ffmpeg-2.3.3/android/armv7-a)

  • create Application.mk

    APP_ABI := armeabi-v7a

    APP_PLATFORM := android-8

  • run ndk-build and use the generated libraries in my android project.

  I really need help on continuing, so every answer is received with great attention and pleasure.

  Later Edit :
  Would it be possible to somehow build ffmpeg.exe as a library and call its main with the exact same parameters as the original exe ? I do not want to run ffmpeg as a standalone executable, but have it integrated within the project. Something like http://www.roman10.net/how-to-port-ffmpeg-the-program-to-androidideas-and-thoughts/ What downsides would this approach have ?

  Later edit 2 : if this is possible by using MediaMuxer or other APIs added in android 4.3 I am open to it you sample codes are provided. I did look over the MediaCodec and MediaMuxer samples also Grafik and haven’t found a proper way to do what I wanted. I prefer ffmpeg approach better if it works

• ffmpeg get stream from card cannot find capture pin

  11 août 2014, par KonradPrg

  I am trying to capture video from card using ffmpeg, but I cant get a Capture pin.
  I write a following command :

  ffmpeg -list_devices true -f dshow -i dummy

  And get the information :

  [dshow @ 0000000002b1f680] DirectShow video devices
  
  [dshow @ 0000000002b1f680]  "MB86H55-REB PCI Capture(0)"
  
  [dshow @ 0000000002b1f680]  "MB86H55-REB PCI Capture(1)"
  
  [dshow @ 0000000002b1f680]  "MB86H55-REB PCI Capture(2)"
  
  [dshow @ 0000000002b1f680]  "MB86H55-REB PCI Capture(3)"
  
  [dshow @ 0000000002b1f680]  "MB86H55-REB PCI Capture(4)"
  
  [dshow @ 0000000002b1f680]  "MB86H55-REB PCI Capture(5)"
  
  [dshow @ 0000000002b1f680]  "MB86H55-REB PCI Capture(6)"
  
  [dshow @ 0000000002b1f680]  "MB86H55-REB PCI Capture(7)"
  
  [dshow @ 0000000002b1f680] DirectShow audio devices

  So I have got a device which support DirectShow. And after this I’d like to check my support resolution and parameters for this cards.

  ffmpeg -list_options true -f dshow -i video="MB86H55-REB PCI Capture(0)"

  And find me only stream out and none parameters for this card.

  [dshow @ 0000000002b7f680] DirectShow video device options
  
  [dshow @ 0000000002b7f680]  Pin "Stream Out"
  
  [dshow @ 0000000002b7f680]  Pin "Virtual Stream Out"

  And I cannot get any stream via ffmpeg or even I cannot show preview.
  Has got any idea why it doesn’t work ?

• ffmpeg + i2s adafruit microphone card + rasp 3 B

  22 août 2018, par Mikhaël Gerbet

  I have a Raspberry pi 3 B with Strech OS + a Microphone card (i2s mems adafruit).

  I would like to make a simple record with ffmpeg (to stream after).

  When a do :

   $ arecord -D dmic_sv -c2 -r 48000 -f S32_LE -t wav -V mono -v out.wav

  it works !

  But when i try with ffmpeg, i have a audio file without sound :/

  $ ffmpeg -f alsa -ac 2 -ar 44100  -i default:CARD=sndrpisimplecar -t 10 out.wav

  The difference between the audio file generated by arecord and ffmpeg is the bits. 32 bits with arecord and 16 bits with ffmpeg.

  Maybe the problème is here ? i don’t know...

  Thank you for your help :)