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• ffmpeg missing frames when generating video from images

  5 décembre 2011, par Eder

  I have been trying to generate a video from a set of images using ffmpeg. Everything seems to be working, but when I watch the video I notice that some of the images are missing. I checked the output from ffmpeg, and it seems that it processes all the source images. Has any of you experienced the same problem ? I'm using mp4 format and mpeg4 codec.

  Interestingly, if I use avi format, without specifying any codec, I can see those missing images correctly (although the video seems to be jumping from one image to the next quite irregularly). By the way, I have only 14 images, so I set a frame rate of 6. The mp4 video is smooth with these settings, but the avi is quite 'jumpy'.

  Thanks in advance.

• iPad Doesn't Render H.264 Video with HTML5

  5 octobre 2011, par jgoldberg

  I have some H.264-encoded videos which render in HTML5 correctly in the web browser, but do not render correctly on the iPad. When I use a H.264 video I downloaded off the internet, my video renders correctly on the iPad, so it is not an HTML problem.

  Here is the ffmpeg info about my videos —

  My original .mov video :

  Seems stream 1 codec frame rate differs from container frame rate : 6000.00 (6000/1) -> 30.00 (30/1)

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'a_video.mp4' :

  Metadata :

  major_brand     : qt  
  
  minor_version   : 537199360
  
  compatible_brands: qt  

  Duration : 00:00:42.74, start : 0.000000, bitrate : 220 kb/s

  Stream #0.0(eng): Audio: aac, 44100 Hz, stereo, s16, 94 kb/s
  
  Stream #0.1(eng): Video: h264, yuv420p, 762x464, 122 kb/s, 30 fps, 30 tbr, 3k tbn, 6k tbc

  After using Handbrake to convert my .mov to a mp4, yet doesn't render on the iPad :

  Seems stream 0 codec frame rate differs from container frame rate : 180000.00 (180000/1) -> 29.97 (30000/1001)

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'a_video.m4v' :

  Metadata :

  major_brand     : mp42  
  
  minor_version   : 0
  
  compatible_brands: mp42isomavc1  
  
  encoder: HandBrake 0.9.5 2011010300  

  Duration : 00:00:42.77, start : 0.000000, bitrate : 169 kb/s

  Stream #0.0(und) : Video : h264, yuv420p, 752x464 [PAR 381:376 DAR 381:232], 35 kb/s, PAR 145161:141376 DAR 145161:87232, 29.97 fps, 29.97 tbr, 90k tbn, 180k tbc
  Stream #0.1(eng) : Audio : aac, 44100 Hz, stereo, s16, 128 kb/s

  Here is a .mp4 I found online which does render on the iPad :

  Seems stream 1 codec frame rate differs from container frame rate : 180000.00 (180000/1) -> 25.00 (25/1)

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'a_video_3_emu.mp4' :

  Metadata :
  major_brand : M4VP
  minor_version : 1
  compatible_brands : M4VPM4A mp42isom
  encoder : CoreMediaAuthoring 677, CoreMedia 420.17, i386

  Duration : 00:01:38.01, start : 0.000000, bitrate : 1023 kb/s

  Stream #0.0(und) : Audio : aac, 32000 Hz, mono, s16, 97 kb/s
  Stream #0.1(und) : Video : h264, yuv420p, 480x360 [PAR 1:1 DAR 4:3], 914 kb/s, 25 fps, 25 tbr, 90k tbn, 180k tbc

  Does anyone see something wrong with the way I am encoded my videos ?

  Edit

  At first my theory was that the iPad was sensitive to different container formats ; but that appears not to be the case. I took a video which does render correctly on the iPad and converted it to a .mov, and it still played correctly on the iPad. So there must be a problem with how the iPad deals with the underlying H.264 stream.

• Anomalie #2442 (Fermé) : Insertion de vidéo dans un article

  5 décembre 2011, par spip factory

  Il est impossible de joindre un document sur un SPIP 3.0.0-beta SVN [18772], si l’on clic sur le bouton Ajouter un document on ouvre le lien http://spipfactory.com/ecrire/?exec=article&id_article=497&ajouter=oui ors celui-ci nous indique Ajouter une image confirmer sur http://grml.eu (...)