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• ffmpeg Live Input MP4 Error [migrated]

  3 mars 2013, par Brianjs

  Currently I have a mic and a webcam connected to my computer. I am running ffmpeg on CentOS 6.3.

  When I try to record a video without audio by :

  ffmpeg -y -f video4linux2 -t 15 -s 640x480 -r 25 -i /dev/video0 /home/irdb/Desktop/out2.mp4

  it runs perfectly and I get a nice video. However when I try to run with audio included by :

  ffmpeg -y -f video4linux2 -t 15 -s 640x480 -r 25 -i /dev/video0 -f alsa -ar 22050 -ab 64k -ac 2 -i default /home/irdb/Desktop/out2.mp4

  It errors out and prints :

  [NULL @ 0x1e33fc0] Codec is experimental but experimental codecs are not enabled,      see -strict -2
  
  Output #0, mp4, to '/home/irdb/Desktop/out2.mp4':
  
  Stream #0:0: Video: h264, yuv420p, 640x480, q=-1--1, 90k tbn, 25 tbc
  
  Stream #0:1: Audio: none, 22050 Hz, 2 channels, flt, 128 kb/s
  
  Stream mapping:
  
  Stream #0:0 -> #0:0 (rawvideo -> libx264)
  
  Stream #1:0 -> #0:1 (pcm_s16le -> aac)
  
  Error while opening encoder for output stream #0:1 - maybe incorrect parameters such    as bit_rate, rate, width or height

  I assume this has to do with the first error as when I use something like mpg it works just fine. However I plan on streaming this live and want mp4 format as that is pretty much supported by all browsers (Firefox with flash fallback).

  Does anyone know how to get the audio to work without additional processing (as I want to stream live and not write to a file eventually).

• HTTP Live Streaming Mac app

  4 mars 2013, par Diederik Hoogenboom

  I am developing a Mac app which needs to provide a HTTP Live Stream (just the last 2 seconds or so) for the main screen (Desktop).

  I was thinking of the following process :

  1. Create a AVCaptureSession with a AVCaptureScreenInput as input (sessionPreset = AVCaptureSessionPresetPhoto)
  2. Add a AVCaptureVideoDataOutput output to the session
  3. Capture the frames (in kCVPixelFormatType_32BGRA format) in captureOutput:didDropSampleBuffer:fromConnection : and write these to a ffmpeg process for segmenting (using a pipe or something) that creates the MPEG-TS and playlist files.
  4. Use an embedded HTTP server to server up the segmented files and playlist file.

  Is this the best approach and is there is no way to circumvent the ffmpeg part for encoding and segmenting the video stream ?

  What is the best way to pipe the raw frames to ffmpeg ?

• ios http live black screen

  11 mars 2013, par jagsler

  In my ios app I am trying to play videos using http live streaming. The playing goes well until I decide to use the scrubber and skip to some point that hasn't buffered yet. From that moment the audio goes on but the videos goes black.

  I've converted my .MP4 videos with the following command :

  avconv -y -i video.mp4 -f mpegts -acodec libmp3lame -ar 48000 -ab 64k -s 640x480 -vcodec libx264 -b 64k -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -subq 7 -trellis 0 -refs 0 -coder 0 -me_range 16 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 200k -maxrate 64k -bufsize 64k -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 30 -qmax 51 -qdiff 4 -level 30 -aspect 640:480 -g 30 -async 2 sample_64.ts

  I did this with multiple bitrates (64, 150, 240, 440 and 640) and created one .m3u8 that contains the different streams. After converting I used the mediafilesegmenter to split the video in segments of each 10 seconds.

  After scrubbing the following appears in the output window :

  2013-03-08 17:30:21.827 Geschiedenis Trainer[88129:19a03] [MPAVController] Autoplay: Disabling autoplay for pause
  
  2013-03-08 17:30:21.827 Geschiedenis Trainer[88129:19a03] [MPAVController] Autoplay: Disabling autoplay
  
  2013-03-08 17:30:21.977 Geschiedenis Trainer[88129:19a03] [MPAVController] Autoplay: _streamUnlikelyToKeepUp: 1 -> 0
  
  2013-03-08 17:30:21.978 Geschiedenis Trainer[88129:19a03] [MPAVController] Autoplay: Skipping autoplay, disabled (for current item: 1, on player: 0)
  
  2013-03-08 17:30:21.978 Geschiedenis Trainer[88129:19a03] [MPAVController] Autoplay: _streamRanDry: 0 -> 1
  
  2013-03-08 17:30:21.980 Geschiedenis Trainer[88129:19a03] [MPAVController] Autoplay: Took background task assertion (32) for playback stall
  
  2013-03-08 17:30:21.981 Geschiedenis Trainer[88129:19a03] [MPAVController] Autoplay: Skipping autoplay, disabled (for current item: 1, on player: 0)
  
  2013-03-08 17:30:22.634 Geschiedenis Trainer[88129:19a03] [MPAVController] Autoplay: _streamUnlikelyToKeepUp: 0 -> 0
  
  2013-03-08 17:30:22.634 Geschiedenis Trainer[88129:19a03] [MPAVController] Autoplay: _streamRanDry: 0 -> 1
  
  2013-03-08 17:30:22.667 Geschiedenis Trainer[88129:19a03] [MPAVController] Autoplay: Skipping autoplay, disabled (for current item: 1, on player: 0)
  
  2013-03-08 17:30:22.769 Geschiedenis Trainer[88129:19a03] [MPAVController] Autoplay: Ending background task assertion (32) for playback stall

  The code for my videoplayer :

  self.streamPlayer = [[MPMoviePlayerController alloc] initWithContentURL:movieURL];
  
  [self.view addSubview:self.streamPlayer.view];
  
  [self.streamPlayer setFullscreen:YES animated:YES];

  This problem does not occur when skipping to a point that has already been buffered.