Recherche avancée

Sur d’autres sites (6997)

• avcodec_decode_video2 takes long time to decode wmv

  22 février 2013, par Mike Versteeg

  I have written a player using the ffmpeg libraries that plays several avi, mp4 and mpg files fine but not wmv. Debugging has shown that the culprit is avcodec_decode_video2 which for some reason takes half a second to decode a single wmv frame. I have tested and confirmed this with multiple wmv files, even those with much lower resolution then other files that play successfully. Anyone has a clue what I'm doing wrong ?

  PS : log shows "Extra data : 8 bits left, value : 0" and "parser not found for codec wmav2, packets or times may be invalid." for WMV files.

  UPDATE :
  Further examination has shown the call to avcodec_decode_video2 is not slow, instead it seems to return the same frame some 16 times or so, giving the visual impression that it is slow. It does not return an error code so I have no clue why it won't decode all frames in the case of wmv.

  Relevant code :

    AVPacket packet;
  
    av_init_packet(&packet);
  
    done = pOwner->av_read_frame(pFormatCtx, &packet) < 0;
  
    if (!done && packet.stream_index==videostream) 
  
        bool error = pOwner->avcodec_decode_video2(pVCodecCtx, pFrameYUV, &finished, &packet) < 0;

• Error Installing mobile-ffmpeg-full-gpl (4.4.LTS) via CocoaPods - 404 Not Found

  6 mai, par Muhammad Accucia

  I am trying to install mobile-ffmpeg-full-gpl (4.4.LTS) in my iOS project using CocoaPods, but I am encountering a 404 error when CocoaPods attempts to download the framework.

  


  Here is the error message :

  


  \[!\] Error installing mobile-ffmpeg-full-gpl
\[!\] /usr/bin/curl -f -L -o /var/folders/78/lk7swzb97ml4dt3zd9grny0c0000gn/T/d20250201-6580-dtli8h/file.zip https://github.com/tanersener/mobile-ffmpeg/releases/download/v4.4.LTS/mobile-ffmpeg-full-gpl-4.4.LTS-ios-framework.zip --create-dirs --netrc-optional --retry 2 -A 'CocoaPods/1.15.2 cocoapods-downloader/2.1'

% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Dload  Upload   Total   Spent    Left  Speed
0     9    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
curl: (56) The requested URL returned error: 404


  


  It seems like the requested file is no longer available at the specified URL.

  


  Checked the official GitHub releases page for mobile-ffmpeg-full-gpl (4.4.LTS), but I couldn't find the exact file.

  


• ffmpeg http slower than downloading first

  9 août 2017, par Krylic

  When trying to get a clip of a video from a remote source
  Input source :
  

  ffprobe version 3.3.2-static http://johnvansickle.com/ffmpeg/  Copyright (c) 2007-2017 the FFmpeg developers
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'http://website.com/video.mp4':
 Metadata:
   major_brand     : mp42
   minor_version   : 0
   compatible_brands: mp42mp41
   creation_time   : 2017-07-13T15:44:58.000000Z
 Duration: 00:57:32.42, start: 0.000000, bitrate: 1939 kb/s
   Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv), 720x480 [SAR 10:11 DAR 15:11], 1745 kb/s, 29.97 fps, 29.97 tbr, 29970 tbn, 59.94 tbc (default)
   Metadata:
     creation_time   : 2017-07-13T15:44:58.000000Z
     handler_name    : Mainconcept MP4 Video Media Handler
     encoder         : AVC Coding
   Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 189 kb/s (default)
   Metadata:
     creation_time   : 2017-07-13T15:44:58.000000Z
     handler_name    : Mainconcept MP4 Sound Media Handler

  Current command :
  ffmpeg version 3.3.2-static
  ffmpeg.linux -threads 2 -y -ss 3273 -i "http://website.com/video.mp4" -an -movflags +faststart -preset veryfast -codec copy /outputfolder/trimmed_video.mp4
  This 5m35.102s to create a 45mb 2min file.

  If I download the file using wget it takes 28s and using ffmpeg only takes 0.243s

  If I add -vn OR -an to the output portion of the command it completes the trim in about 2.101s. Meaning it’s faster to download the two stream and merge them myself.

  Can anyone explain this behaviour and why my first command takes so long when on a lot of other video files it’s very fast ?