Newest 'ffmpeg' Questions - Stack Overflow

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• Can't install FFMPEG on OS X Mavericks

  15 novembre 2013, par CristianOrellanaBak

  I have an error when install FFMPEG through homebrew on OS X Mavericks running this command brew install ffmpeg :

  Error: ffmpeg dependency x264 was built with the following
  C++ standard library: libstdc++ (from clang)
  
  This is incompatible with the standard library being used
  to build ffmpeg: libc++ (from clang)
  
  Please reinstall x264 using a compatible compiler.
  hint: Check https://github.com/mxcl/homebrew/wiki/C++-Standard-Libraries
  

  The complete history is : I has installed FFMPEG on Mountain Lion (that worked fine), but when upgrade it to Mavericks, FFMPEG fails to create an video in my Ruby on Rails app : Ruby on Rails : FFMPEG fails after upgrade Mountain Lion to Mavericks

  Some idea or recommendation??

  Thank you very much!

• RTSP to HTTP Live Streaming (iOS)

  15 novembre 2013, par user2964075

  I have RTSP feed coming from my IP Camera as my source input and need to publish it to HTTP Live Streaming (HLS) for playback on iOS devices. I have already tried RTSP-to-RTSP on iOS and it worked; this time I want to try RTSP-to-HLS. I already have Wowza and ffmpeg installed but I just don't know what commands I should run to produce HLS. I've googled for the right commands but I just couldn't find them. What should I run?

  Safari supports HLS. Does it also mean that UIWebView supports HLS as well?

• FFMPEG : from jpg to avi it's ok, but with bad size and quality

  14 novembre 2013, par user523129

  I have six .jpg images with a size 350x400 (WxH). I want to turn them into an avi file of a good quality (but not too heavy) and with same dimensions

  I'm doing:

  /var/www/html/folder/ffmpeg/ffmpeg -y -r 0.5 -i myfolder/434420image%05d.jpg -vcodec mpeg4 -s qcif -r 0.5 myfolder/434420img_tmp.avi
  

  And I'm having the avi file, but with a size of 127x142 and with a terrible resolution.

  What am I doing wrong?

  Thanks a lot

• How can I acheive the best overall FLV quality with FFMPEG ?

  14 novembre 2013, par dcolumbus

  First of all, FFMPEG has the worst documentation of all time, and secondly, the syntax is so trivial that it's often hard to understand what some lines are doing.

  What I'm looking to accomplish would be the best quality FLV with the lowest file size. After all, isn't that everyone's goal? These videos will be streamed if that makes any difference.

  Do any of you have some command lines that could do this?

  For now, my video(s) are no wider than 320px, and some are widescreen, so their heights are a little smaller than 240px. As it stands, the quality of the converted FLVs is quite poor.

  Current command:

  > ffmpeg -i video.mov -ar 22050 -ab 32 -f flv -s 320x240 -aspect 4:3 video.flv
  

• Settings required to set to emulate the FFMPEG '-sameq' flag when using libavcodec

  14 novembre 2013, par Jonathan Websdale

  Currently attempting to use libavcodec to transcode MP4 (MPEG4 and H264) and MPG (MPEG2) video files into .MP4, .MPG and .AVI files. Have done this previously using FFMpeg.exe with use of the '-sameq' flag to retain the same/similar quality output file to that of the input file.

  Now using av_open_input_file, av_read_frame and avcodec_decode_video2 to open, read and decode the input file, then assigning a AVCodecContext and encoding the data using avcodec_encode_video. However the output file video quality is pretty poor.

  These are the AVCodecContext settings I'm using?:-

  codecContextOutput->width = SAME AS INPUT FILE;
  codecContextOutput->height = SAME AS INPUT FILE;
  codecContextOutput->pix_fmt = SAME AS INPUT FILE;
  /* frames per second */
  AVRational ar; 
  ar.num = 1;
  ar.den = 25;
  codecContextOutput->time_base = ar;
  codecContextOutput->gop_size = 10; /* emit one intra frame every ten frames */
  codecContextOutput->max_b_frames=1;
  codecContextOutput->bit_rate = 480000;
  

  Does anybody know the additional settings needed to emulate the '-sameq' setting or what additional settings are needed in the AVCodecContext to improve the output quality?