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• libFLAC/cpu.c : Simplify OS SSE support detection.

  28 juillet 2014, par Erik de Castro Lopo

  libFLAC/cpu.c : Simplify OS SSE support detection.
  Simplify the code that tries to detect whether OS supports SSE instructions.
  a) Linux : "old" vs "new" sigaction
  OBSOLETE_SIGCONTEXT_FLAVOR was disabled in Mar 2007 in commit 1ca3a445f.
  
  According to <http://unixhelp.ed.ac.uk/CGI/man-cgi?sigaction>: "Support for
  
  SA_SIGINFO was added in Linux 2.2" (released in Jan 1999). If noone wants to
  
  use FLAC with Linux kernel 2.0 then it’s safe to delete this code.
  b) MSVC : try/catch vs. sigill_handler
  TRY_CATCH_FLAVOR was enabled in Jan 2009 in commit a832ef32. According to the
  
  comment in cpu.c, "sigill_handler flavor resulted in several crash reports on
  
  win32". Also this sigill_handler flavor is not thread-safe.
  c) MinGW : fxsave/fxrestore vs. sigill_handler
  The code was added Mar 2014 in commit 99d5154f. It’s better to use FXSR flavor
  
  instead of sigill_handler flavor. The reasons are the same as for MSVC.
  Patch-from : lvqcl <lvqcl.mail@gmail.com>
  

  • [DH] src/libFLAC/cpu.c

• ffmpeg output + issues

  3 octobre 2014, par Ford

  I am trying to get ffmpeg to work using PHP, in its most basic format, just as a test before i develop my code further.

  However i can not get it to work and get no error messages or indications to what is wrong :-(

  i am trying :

  echo exec("/usr/bin/ffmpeg -y -i /home/xxxxxx/public_html/videos/1746/0765916.avi /home/xxxxxx/public_html/videos/1746/test.mp4"); 

  this is creating a 0kb file, but nothing else :-(
  i get no error message (or anything else !)

  (i have error_reporting turned ON and nothing is displayed in browser or server logs)

  if i add the below to get the codecs available :

  echo exec("ffmpeg -formats");

  this just outputs "worse."

  I do not have access to command line, as i am using a shared hosting server.

  I have had the host run the above from command line, and they say it says "codec not found" or words to the effect.

  is there any way i can get any error output into my php file so i can see what is happening.

  Also how do i go about installing codecs, if this is the problem (the host will install them, but have mentioned they have never installed a codec on a Linux box, so would be grateful if i could point them to any install info too)

  Thanks in advance !

  EDIT :

  after adding in the code that @stewe suggests, this is the output when trying to convert to mp4

  (i can convert to to other formats fine )

  FFmpeg version SVN-r0.5.10-4:0.5.10-1, Copyright (c) 2000-2009 Fabrice
  
  Bellard, et al. configuration: --extra-version=4:0.5.10-1
  
  --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libdirac --enable-libgsm --enable-libopenjpeg --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --disable-stripping --disable-vhook --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libfaad --enable-libdc1394 --enable-shared --disable-static libavutil 49.15. 0 / 49.15. 0 libavcodec 52.20. 1 / 52.20. 1 libavformat 52.31. 0 /
  
  52.31. 0 libavdevice 52. 1. 0 / 52. 1. 0 libavfilter 0. 4. 0 / 0. 4. 0 libswscale 0. 7. 1 / 0. 7. 1 libpostproc 51. 2. 0 / 51. 2. 0 built on
  
  Feb 16 2013 10:07:01, gcc: 4.4.5 Input #0, avi, from
  
  '/home/xxxxx/public_html/videos/1746/0765916.avi':
  
  Duration: 00:01:37.56, start: 0.000000, bitrate: 868 kb/s Stream #0.0:
  
  Video: mpeg4, yuv420p, 480x272 [PAR 1:1 DAR 30:17], 25 tbr, 25 tbn, 25
  
  tbc Stream #0.1: Audio: mp3, 48000 Hz, stereo, s16, 128 kb/s Output
  
  #0, mp4, to '/home/xxxxx/public_html/videos/1746/test.mp4':
  
  Stream #0.0: Video: mpeg4, yuv420p, 480x272 [PAR 1:1 DAR 30:17],
  
  q=2-31, 200 kb/s, 90k tbn, 25 tbc Stream #0.1: Audio: 0x0000, 48000
  
  Hz, stereo, s16, 64 kb/s Stream mapping: Stream #0.0 -> #0.0 Stream
  
  #0.1 -> #0.1 [mpeg4 @ 0x9fb7880]removing common factors from framerate Unsupported codec for output stream #0.1

  If anyone can help as to how to fix this issue, as i would ideally like to convert to mp4

• ffmpeg and Red5 Issue : Increase in number of ffmpeg simultaneous streams to Red5 resulting in packet loss

  30 octobre 2014, par kajarigd

  I have a screen sharing app written in flex, using which one person can share his screen with another person via Red5 server (Version : 1.0.3). Platform is Windows Server 2008. Now, I want to load test this Red 5 server to find out maximum how many simultaneous screen sharing session it can allow, without any quality compromise. By quality I mean, speed of transmission and no data loss during transmission. I simulated the load using ffmpeg command.

  For this, instead of transmitting a live captured screen, I am transmitting (uploading) a FLV file stored in my local to the Red5 server using ffmpeg command. In the receiving client side, I am starting to download (transmitting) this same FLV file after 5 secs since the upload has started. This is working fine when I am running this test for less than 10 pairs of upstreaming-downstreaming sessions. But, when the number is increasing beyond 10, I am observing significant packet loss in transmission.

  Here are the commands I am running in a loop. The loop count is the number of streaming pairs.

  1. upstreaming : ffmpeg -re -i  -f flv -ar 22050 "rtmp://" -report
  2. downstreaming : ffmpeg -re -i "rtmp:// live=1"  -report

  The and are set in such a way, that in the downstream I will download the same uploaded file. "rtmp ://" are the same in both the cases. I am not doing the upstream in record mode, hence, no physical file is getting saved in the server side. When I am analyzing the file I received in the receiving client side, it is a poor quality video due to frame loss. Uploading and downloading machines are two different machines. I ran the test for many hours, repeating the same 10 simultaneous streaming sets. Each set is consistently giving the same results.

  What is puzzling me is, this is working fine without any packet loss for less that 10 simultaneous streaming. I searched about it in various forums, but none of the answers were applicable for this scenario. For a while I was thinking that Red5 has limited capacity, but I found many posts saying Red5 can easily scale up to take very big load. Does that mean, the problem is in my configuration ? I am not sure which are to focus on.

  An example log snippet :

  Lots of missing data at downstream side. For e.g. between frames 101 and 102 there is a difference of 25 sec. On replaying the video there is a stoppage for this much time.In this time gap all the frames are lost.

  frame=  101 fps=1.0 q=14.5 size=    2650kB time=00:01:41.00 bitrate= 214.9kbits/s
  
  frame=  102 fps=1.0 q=13.2 size=    2763kB time=00:02:06.00 bitrate= 179.6kbits/s

  Any help is appreciated !