Recherche avancée

Sur d’autres sites (7455)

• How do I convert a 3D SBS dual-fisheye image to 3D SBS dual-equirectangular with only open-source tools ? [closed]

  21 octobre 2024, par Ethan T

  Canon has released a new 3D VR lens for their RF mount and I recently rented it to see what it's like to work with. Unfortunately, they charge a subscription fee for their conversion software, which I've also found to be inconveniently limited in real-world use cases. Thus I'm interested in an open-source approach to converting the video captured by this lens using something like ffmpeg.

  


  The video is dual-fisheye and the Canon tool produces dual-equirectangular side-by-side video. I would like to perform this same conversion in ffmpeg or a similarly-powerful open-source tool.

  


  Related questions exist but aren't quite correct. Most dual-fisheye input seems to be used to create 360-degree 2D video, not 3D SBS.

  


• avformat/http: increase BUFFER_SIZE to MAX_URL_SIZE + HTTP_HEADERS_SIZE

  11 mai 2020, par Joey Smith

  avformat/http: increase BUFFER_SIZE to MAX_URL_SIZE + HTTP_HEADERS_SIZE
  Some real-world sites use an authorization header with a bearer token ; when
  
  combined with lengthy request parameters to identify the video segment,
  
  it's rather trivial these days to have a request body of more than 4k bytes.
  MAX_URL_SIZE is hard-coded to 4k bytes in libavformat/internal.h, and
  
  HTTP_HEADERS_SIZE is 4k as well in libavformat/http.h, so this patch increases
  
  the buffer size to 8k, as that is the default request body limit in Apache, and
  
  most other httpds seem to support at least as much, if not more.
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] libavformat/http.c

• FFMpeg generates still video

  19 juillet 2013, par Jason Muchow

  I'm doing a simple test of ffmpeg. I'd like to use it for thumbnail generation / video grabbing for a website I'm developing. I'm currently using VLC to grab a single frame and then generate a thumbnail, but it's rather slow and a bit cumbersome.

  The problem is that the video I'm using (from my own pc) is generated by security camera software and it has an odd video format. When I open it (.bvr) in VLC, it plays very, very fast. A 10 second video goes by in about 2.5 seconds. Additionally, using a simple convert with ffmpeg "ffmpeg -i test.bvr output.avi" generates a proper-length video (10 seconds), but the video frame never changes. (It's a still image)

  Test file and test output file :

  • https://dl.dropbox.com/u/95418255/test.bvr
  • https://dl.dropbox.com/u/95418255/output.avi

  I think this is primarily caused by the fact that the IP cameras may only generate 5-7 fps but the security software doesn't know better and writes it as if it should be 24/30 fps.

  FFMpeg Reports : [m4v @ 00000000002cec60] Estimating duration from
  bitrate, this may be inaccurate Input #0, m4v, from 'test.bvr' :
  Duration : N/A, start : 0.000000, bitrate : N/A Stream #0:0 : Video : mpeg4
  (Simple Profile), yuv420p, 640x480 [SAR 1:1 DAR 4:3], 5 tbr, 1200k
  tbn, 5 tbc Output #0, avi, to 'output.avi' : Metadata : ISFT
   : Lavf54.25.104 Stream #0:0 : Video : mpeg4 (FMP4 / 0x34504D46),
  yuv420p, 640x480 [SAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 5 tbn, 5 tbc
  Stream mapping :

  Stream #0:0 -> #0:0 (mpeg4 -> mpeg4) Press [q] to stop, [?] for help
  frame= 50 fps=0.0 q=2.0 Lsize= 244kB time=00:00:10.00 bitrate=
  199.7kbits/s video:237kB audio:0kB subtitle:0 global headers:0kB muxing overhead 2.877066%**

  Any help is appreciated !