Recherche avancée

Sur d’autres sites (8962)

• Webpage with several IP-cameras' streams

  28 mars 2013, par JustLogin

  I have some live RTSP streams from IP-cameras with H.264 video and g-729 sound codecs. I need to display them on a webpage, which could be opened in any popular browser in Windows, Linux and Mac. Also, there must be an option to record and to save to user's PC a video from any stream to flv file , using Start/Stop recording button.
  The problem is, I don't know what technologies to choose : all solutions which I came up with, have several problems.

  The first variant is to transcode stream to RTMP with FFmpeg, changing audio codec to MP3.That way it can be played with a small Flash app. It works, but I don't know, how to save video because the .flv-writing library requires Bitmaps and ByteArray sound data chunks as input. It's not a problem to get images from Video class, but I have no idea about sound : SoundMixer class couldn't recieve any data from Video (or NetStream) with it's computeSpectrum method. So , impossibility of writing sound to .flv is the only problem of this solution.

  Another variant is to use java applet, based on Xuggler library. It work's fine, but the library is VERY huge, and "applet's" size is near 40mb !

  I also tryed Silverlight (it's problem is, it isn't popular, so everyone have to download it for 1 app only) and HTML5 (which does not allow capturing sound from incoming live stream, like Flash), but they give no solutions too. So I don't know, how to realize this project, can you give me any idea please ?

• Error while extracting subtitle from mkv or m2ts to srt with FFmpeg

  14 février 2013, par user2071701

  I need to extract subtitles from different video files to .srt format (to use it in html5 video).
  I tried a lot of variant i found with google. But every time i get this error :

  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  I think, this error means that ffmpeg can decode source subtitle but cant encode it to .srt format. All codecs a enabled (i compiled the later ffmpeg version from git a few times with a different configuration).

  Here is the output :

      # /usr/local/bin/ffmpeg -i /var/video/sources/Balbesy1.m2ts -an -vn  -copyinkf -scodec srt -f srt -y  sub.srt
  
  ffmpeg version N-49947-g9f16cb9 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Feb 14 2013 14:26:10 with gcc 4.4.5 (Debian 4.4.5-8)
  
    configuration: --enable-encoder=dvdsub --enable-decoder=dvdsub --enable-decoder=pgssub --enable-encoder=srt --enable-decoder=srt --enable-encoder=srt --enable-decoder=srt
  
    libavutil      52. 17.101 / 52. 17.101
  
    libavcodec     54. 91.103 / 54. 91.103
  
    libavformat    54. 63.100 / 54. 63.100
  
    libavdevice    54.  3.103 / 54.  3.103
  
    libavfilter     3. 37.101 /  3. 37.101
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
  [mpegts @ 0x2719040] Stream #5: not enough frames to estimate rate; consider increasing probesize
  
  [mpegts @ 0x2719040] Could not find codec parameters for stream 5 (Subtitle: hdmv_pgs_subtitle ([144][0][0][0] / 0x0090)): unspecified size
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  [NULL @ 0x271fec0] start time is not set in estimate_timings_from_pts
  
  Input #0, mpegts, from '/var/video/sources/Balbesy1.m2ts':
  
    Duration: 01:18:11.89, start: 599.958300, bitrate: 37378 kb/s
  
    Program 1 
  
      Stream #0:0[0x1011]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc
  
      Stream #0:1[0x1100]: Audio: dts (DTS-HD MA) ([134][0][0][0] / 0x0086), 48000 Hz, 5.1(side), fltp, 768 kb/s
  
      Stream #0:2[0x1101]: Audio: dts (DTS-HD MA) ([134][0][0][0] / 0x0086), 48000 Hz, 5.1(side), fltp, 768 kb/s
  
      Stream #0:3[0x1102]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 448 kb/s
  
      Stream #0:4[0x1103]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 448 kb/s
  
      Stream #0:5[0x1200]: Subtitle: hdmv_pgs_subtitle ([144][0][0][0] / 0x0090)
  
  Output #0, srt, to 'sub.srt':
  
      Stream #0:0: Subtitle: srt
  
  Stream mapping:
  
    Stream #0:5 -> #0:0 (pgssub -> srt)
  
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  sorry for my english

• Something wrong with my m3u8 bandwidth value

  6 octobre 2012, par Jason

  I use ffmpeg to encode my sample videos following the recommanded bitrates in Technical Note TN2224, then use HLS tools to segment it and create playlists, finally create the variant plist file "all.m3u8"
  I used the validation tool to validate my HLS content, it ended up showing except for the 64k audio only bandwidth is low, others are stay in the same bandwidth, I opened "all.m3u8" using text editor and seeing that all other bitrate contents are using the same bandwidth. No matter how I change parameters in the ffmpeg command, I still can't correct them. The following command is the one I used to encode contents :
  ffmpeg -i input.m4v -acodec libfaac -vcodec libx264 -s 480x360 -b 350k -r 29.97 -vpre medium output.mp4

  The following command is for generating the segments and plists :
  mediafilesegmenter -b http://www.example.com/stream/ -I -f ~/Documents/sample/ output.mp4

  The following command is for generating the all.m3u8 :
  

  variantplaylistcreator -o all.m3u8 http://www.example.com/stream/110/prog_index.m3u8 ~/Documents/sample/110/prog_index.m3u8 -iframe-url http://www.freeyourteam.com/stream/110/iframe_index.m3u8 http://www.example.com/stream/200/prog_index.m3u8 ~/Documents/sample/200/prog_index.m3u8 -iframe-url http://www.freeyourteam.com/stream/200/iframe_index.m3u8 http://www.example.com/stream/350/prog_index.m3u8 ~/Documents/sample/350/prog_index.m3u8 -iframe-url http://www.freeyourteam.com/stream/350/iframe_index.m3u8 http://www.example.com/stream/550/prog_index.m3u8 ~/Documents/sample/550/prog_index.m3u8 -iframe-url http://www.freeyourteam.com/stream/550/iframe_index.m3u8 http://www.example.com/stream/64/prog_index.m3u8 ~/Documents/sample/64/prog_index.m3u8

  and in my "all.m3u8", the bandwidths are all 523894 :
  

  Please allow me to ask two more basic questions :
  In the tech note, recommanded bitrates are 64 Kbps, 110 Kbps, 200 Kbps, 350 Kbps, 550 Kbps, I wonder if this value includes the audio bitrate or exclude the audio.
  How do you insert keyframe to segment ? Because in the document it says :"You must include at least one keyframe per segment, preferably more. If you only include one, put it at the beginning of the segment." I don't quite get how you can do it.
  Thank you very much for your help and I do appreciate your time.