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• How to convert large sequence of static gifs to video ?

  29 mars 2018, par Quinn

  I am trying to convert a large amount of static gifs(not animated) into video, but am completely lost on how to proceed.

  Specifications :

  QTY : 7,500 - 10,000 static .gif images

  File Size : 11kb ea.

  Image Dimensions : 580x580px

  File Naming : I_20000880002-20000880626.gif, I_20000880626-20000882042.gif, I_20000882042-20000891054.gif, etc...

  I have tried many different things, but none of them have worked. First, I tried Adobe Media Encoder. That failed, it couldn’t handle 10k files. I tried ffmpeg, which didn’t really work. The code I used is as follows :

  ffmpeg -r 60 -f image2 -s 580x580 -i pic%04d.png -vcodec libx264 -crf 25  -pix_fmt yuv420p test.mp4

  This didn’t work because it was trying to import .png files. I then changed the .png extension to .gif in the code. So :

  ffmpeg -r 60 -f image2 -s 580x580 -i pic%04d.gif -vcodec libx264 -crf 25  -pix_fmt yuv420p test.mp4

  I’m not an expert in ffmpeg by any means, so the code I executed might not have the proper syntax, at least in regards to -i pic%04d.gif. I suppose I could convert the .gifs into .pngs, then run the original code, but I’m not totally sure how to do that with ffmpeg.

  If anyone has any tips, they would be most appreciated. Also, I am using Windows 10 but I do have the linux subsystem installed. Thanks.

• Compressing a Video for HLS Streaming

  12 mars 2018, par jAndy

  I’m in the situation where I have a source file (very high quality, direct output from FCPX) which is in 1080p resolution.

  I use ffmpeg to create a 240, 360, 480 and 720 version to have an adaptive stream quality via HLS, so far so good. My question is about the strategy I’m using.
  Right now, I always use the original file as input for ffmpeg. I was wondering if it wouldn’t be a better idea to convert from 1080 to 720 with full compression algorithms and after that, just re-scale from 720 to 480, 360 and 240.

  I’m not really into video compression and ffmpeg, so I’d just like to hear some expert opinions on this approach. Is there any advantage to always go "all the way" (original file -> compressed/rescaled file) ?

• ffmpeg command line for capturing (and recording) audio and video in 720p from decklink card using Windows 7

  6 janvier 2018, par Huron

  I am trying to capture audio and video from a blackmagic decklink capture card using Windows 7 @ 720p, but I cant seem to get the ffmpeg command line settings right.

  ffmpeg -list_devices true -f dshow -i dummy

  [dshow @ 02457a60] DirectShow video devices
  
  [dshow @ 02457a60]  "Blackmagic WDM Capture"
  
  [dshow @ 02457a60]  "Decklink Video Capture"
  
  [dshow @ 02457a60] DirectShow audio devices
  
  [dshow @ 02457a60]  "Decklink Audio Capture"

  ffmpeg -list_options true -f dshow -i video="Decklink Video Capture"

  [dshow @ 03c2ea20] DirectShow video device options
  
  [dshow @ 03c2ea20]  Pin "Capture"
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=720x486 fps=29.97 max s=720x486 fps=29.97
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=720x486 fps=23.976 max s=720x486 fps=23.976
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=720x576 fps=25 max s=720x576 fps=25
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=720x486 fps=59.9402 max s=720x486 fps=59.9402
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=720x576 fps=50 max s=720x576 fps=50
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1920x1080 fps=23.976 max s=1920x1080 fps=23.976
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1920x1080 fps=24 max s=1920x1080 fps=24
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1920x1080 fps=25 max s=1920x1080 fps=25
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1920x1080 fps=29.97 max s=1920x1080 fps=29.97
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1920x1080 fps=30 max s=1920x1080 fps=30
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1280x720 fps=50 max s=1280x720fps=50
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1280x720 fps=59.9402 max s=1280x720 fps=59.9402
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1280x720 fps=60.0002 max s=1280x720 fps=60.0002

  ffmpeg -list_options true -f dshow -i audio="Decklink Audio Capture"

  [dshow @ 047fea20] DirectShow audio device options
  
  [dshow @ 047fea20]  Pin "Capture"
  
  [dshow @ 047fea20]   min ch=1 bits=16 rate= 48000 max ch=1 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=2 bits=16 rate= 48000 max ch=2 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=4 bits=16 rate= 48000 max ch=4 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=6 bits=16 rate= 48000 max ch=6 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=8 bits=16 rate= 48000 max ch=8 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=10 bits=16 rate= 48000 max ch=10 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=12 bits=16 rate= 48000 max ch=12 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=16 bits=16 rate= 48000 max ch=16 bits=16 rate= 48000

  This is the stream information for my current video/audio source, connected to the decklink card’s hdmi port

  Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422(tv), 1280x720, 59.94 tbr, 10000k tbn, 59.94 tbc
  
  Stream #0:1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s

  Ultimately I will need to display this video on screen. And simultaneously be able to start and stop recording, while the preview keeps playing.

  My idea was to use ffmpeg to capture the video and audio signal and transmit this to a network stream (eg 127.0.0.1:6666). Then use VLC player to display the stream (the preview). And ultimately start and/or stop another ffmpeg to save that same stream to disk.

  In my mind this works, but I am no audio/video expert so if anyone with more experience could help out, I would appreciate it.

  Update :

  I have been able to display the video using ffplay, with the following command :

  ffplay -f dshow -video_size 1280x720 -rtbufsize 702000k -framerate 60 -i video="Decklink Video Capture":audio="Decklink Audio Capture" -threads 2

  Next step is streaming it so I can view the stream (preview) with VLC.

  Tried to use this command :

  ffmpeg -f dshow -video_size 1280x720 -rtbufsize 702000k -framerate 60 -i video="Decklink Video Capture":audio="Decklink Audio Capture" -threads 2 -f mpegts rtp://127.0.0.1:6666?pkt_size=188?buffer_size=65535

  Which does not give any errors, so appears to work. But when I try to open the stream in VLC I get the following error :

  SDP required :
  A description in SDP format is required to receive the RTP stream. Note that rtp :// URIs cannot work with dynamic RTP payload format (65).

  After a bit of reading it seems I should not be streaming to rtp :// but rather to udp ://

  Command became :

  ffmpeg -f dshow -video_size 1280x720 -rtbufsize 702000k -framerate 60 -i video="Decklink Video Capture":audio="Decklink Audio Capture" -threads 2 -f mpegts udp://127.0.0.1:6666?pkt_size=188?buffer_size=65535

  And when I try to open it now in VLC I get no error, no warning, but also no video.

  Time for some more reading.