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• How to install avconv for youtube-dl

  23 janvier 2016, par Hashim

  Up till now, I’ve been using youtube-dl with ffmpeg. I’ve had a few problems doing so, which I posted about in another question, but for the most part, I managed to get ffmpeg set up without a hitch. After having problems converting certain file formats with ffmpeg, I was advised in that question to try and switch to avconv to see whether ffmpeg was indeed the problem, and basically help me troubleshoot, but despite trying for the last 3 hours, I’ve been unable to even get avconv set up.

  So far, I’ve downloaded several of the releases for my Windows 7 x64 operating system from the libav website, each time copying the exact folder structure into the folder where my youtube-dl.exe is, and then making sure that location and the bin folder is in the PATH environment variable. The folder structure looks like this : C:\Program Files (x86)\youtube-dl\usr\bin, where bin contains avconv.exe and the rest of the files that it needs. Does anyone have any clue as to why this isn’t working for me ? It’s beyond me how something so critical to a program as popular as youtube-dl could be so hard and/or badly-documented to get set up.

  Thanks for any help in advance, it’s much appreciated.

  EDIT : Something peculiar that I’ve noticed. When getting rid of all traces of avconv and ffmpeg, youtube-dl throws up the usual error of needing them to convert. But when just the avconv folders are in the necessary places, youtube-dl recognises it as ffmpeg and starts processing the files as such.

• Construct fictitious P-frames from just I-frames [closed]

  25 juillet 2024, par nilgirian

  Some context.. I saw this video recently https://youtu.be/zXTpASSd9xE?si=5alGvZ_e13w0Ahmb it's a continuous zoom into a fractal.

  


  I've been thinking a whole lot of how did they created this video 9 years ago ? The problem is that these frames are mathematically intensive to calculate back then and today still fairly really hard now.

  


  He states in the video it took him 33 hours to generate 1 keyframe.

  


  I was wondering how I would replicate that work. I know by brute force I can generate several images files (essentially each image would be an I-frame) and then ask ffmpeg to compress it into mp4 (where it will convert most of those images into P-frames). I know that. But if I did it that way I calculated it'd take me 6.5 years to render that 9min video (at 30fps, 9 years ago).

  


  So I imagine he only generated I-frames to cut down on time. And then this person somehow created fictitious P-frames in-between. Given that frame-to-frame are similar this seems like it should be doable since you're just zooming in. If he only generated just the I-frames at every 1 second (at 30fps) that work could be cut down to just 82 days.

  


  So if I only want to generate the images that will be used as I-frames could ffmpeg or some other program just automatically make a best guess to generate fictitious P-frames for me ?

  


• hls : Respect the different stream time bases when comparing dts

  21 août 2012, par Michael Niedermayer

  hls : Respect the different stream time bases when comparing dts
  Also adjust the streams timestamps according to their start
  
  timestamp when comparing. This helps getting correctly interleaved
  
  packets if one stream lacks timestamps (such as a plain ADTS
  
  stream when the other variants are full mpegts) when the others
  
  have timestamps that don’t start from zero.
  This probably doesn’t work properly if such a stream is
  
  temporarily disabled (via the discard flags) and then reenabled,
  
  and such streams are hard to correctly sync against the other
  
  streams as well - but this works better than before at least.
  The segment number restriction makes sure all variants advance
  
  roughly at the same pace as well.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavformat/hls.c