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• Why does Android kill a process spawned by the developed application ?

  23 octobre 2013, par uprego

  I have a weird problem that I posted as a comment in Understanding Android Tight loops / Spin-On-Suspend error without any useful further comment.

  Let be here the reproduced comment :

  Is it possible for this to be happening also to android native codes, abstracting
  
   which piece of software would be causing it? It's the only reason I know ffmpeg 
  
  (static binary custom compilation, n2.0.1 tag mint as it clones) is failing to me
  
   on some devices and not in others (but fails in no device when launched over a v
  
  algrind!! that, am now supposing, traps frequently the inner program)

  The problem, briefly, is that a compiled ffmpeg n2.0.1 is running OK in emulator and a Sony device, but failing with a segmentation violation in a Samsung device. The program was ran then from valgrind in that Samsung device, with no fail.

  • I have some clues about what could be happening here. But do you know what is happening ?
  • Can this Samsung phone run this ffmpeg compilation the same good the emulator and the Sony phone do ? If not, what are the next steps (trying - when possible - to avoid the use of the NDK) ?

• Does Facebook multicast or unicast the live videos to its viewers ?

  14 avril 2018, par Kamran Zahoor

  This is how a live stream goes from one broadcaster to millions of viewers :

  1. A broadcaster starts a live video on their phone.
  2. The phone sends a RTMP stream to a Live Stream server.
  3. The Live Stream server decodes the video and transcodes to multiple bit rates.
  4. For each bit rate a set of one-second MPEG-DASH segments is continuously produced.
  5. Segments are stored in a datacenter cache.
  6. From the datacenter cache segments are sent to caches located in the points of presence (a PoP cache).
  7. On the view side the viewer receives a Live Story.
  8. The player on their device starts fetching segments from a PoP cache at a rate of one per second.

  My question is simple. After the step 6, does PoP cache/Edge cache/eNB (edge layer node) multicast a live video content to multiple viewers or unicast each user separately (opening up seperate streams for each user) ?

• Multiple output and one of them with a still image and same audio

  15 juin 2017, par Rafael Linux User

  I have a working ffmpeg command that outputs two videos with different a/v bitrates.

          exec_push ffmpeg -re -y -i input.mp4
  
  
  
                  -c:a aac -c:v libx264   -b:a 64k    -profile:v baseline -level 3.0 -crf 31  -maxrate 190k -bufsize 380k
  
                  -f flv output_320x
  
  
  
                  -c:a aac -c:v libx264   -b:a 96k    -profile:v baseline -level 3.0 -crf 30  -maxrate 330k -bufsize 660k
  
                  -f flv output_480x

  Now, I want do add to this command one more output, that will have an still image and the audio or the input at a low bitrate, but I can’t get it to work :(

          exec_push ffmpeg -re -y -i input.mp4
  
  
  
                  -i "image.png"  -map 0:a -map 1:v
  
                  -c:a aac -c:v libx264  -tune stillimage   -b:a 32k  -profile:v main -level 3.0 -crf 32      -maxrate 64k -bufsize 128k
  
                  -f flv output_audio
  
  
  
                  -c:a aac -c:v libx264   -b:a 64k    -profile:v baseline -level 3.0 -crf 31  -maxrate 190k -bufsize 380k
  
                  -f flv output_320x
  
  
  
                  -c:a aac -c:v libx264   -b:a 96k    -profile:v baseline -level 3.0 -crf 30  -maxrate 330k -bufsize 660k
  
                  -f flv output_480x

  Please, can anyone help me ?

  Thank you