VideoHelp Forum

Try DVDFab and download streaming video, copy, convert or make Blu-rays,DVDs! Download free trial !
+ Reply to Thread
Results 1 to 8 of 8
Thread
  1. I'm trying to use the Reverse function on AVISynth, but whenever I do it, the video becomes very slow and the CPU power goes up.


    Code:
    AudioDub(FFVideoSource("test.wmv", fpsnum = 30000, fpsden = 1001), FFAudioSource("test.wmv"))
    
    Trim(6063,7047)
    Reverse

    Is the Reverse function really that demanding or is there a way to make it run smoothly?
    Quote Quote  
  2. Banned
    Join Date
    Oct 2014
    Location
    Northern California
    Search PM
    Originally Posted by smike View Post
    I'm trying to use the Reverse function on AVISynth, but whenever I do it, the video becomes very slow and the CPU power goes up.
    What kind of hardware are you running this with?
    Quote Quote  
  3. It's a 2 Quad Core CPU with a 64 bit operating system.
    Quote Quote  
  4. Originally Posted by smike View Post
    Is the Reverse function really that demanding or is there a way to make it run smoothly?
    I've never used it but I gave it a test and couldn't get it to always run smoothly. For DVD video it seemd to run at the correct speed in reverse, but when I tried an Xvid encoded video..... not so much. The speed would increase and decrease, but I don't know if it's a decoding issue or whether for video that requires more CPU power to decode it's just going to be inconstant speed-wise. I tried ffms2 and L-Smash.

    For me (I only tested a low resolution standard definition Xvid video, aside from a vob file) CPU usage did increase, but it was still only sitting on 30% or so and none of the individual CPU cores hit 100% (or even close), yet the video wasn't playing smoothly in reverse. Sorry, I don't know why.

    Originally Posted by newpball View Post
    What kind of hardware are you running this with?
    I assume from the question you must know what level of hardware is required, so why keep us in suspense?
    Quote Quote  
  5. Lossy codecs may give slow access (preceding frames to key frame need to be decoded before last one will be accessible) - prerender file to temporary and seek over it faster.
    Quote Quote  
  6. Long GOPs (not necessarily lossy codecs) require a lot of work for random (or backward) seeks -- which is required by the Reverse() function.
    Quote Quote  
  7. Originally Posted by jagabo View Post
    Long GOPs (not necessarily lossy codecs) require a lot of work for random (or backward) seeks -- which is required by the Reverse() function.
    Well - yes, You are 100% right - long GOP instead lossy (albeit mostly long GOP's are also lossy - from non lossy and computationally intense i can imagine only FFV1)
    Quote Quote  
  8. Originally Posted by pandy View Post
    Originally Posted by jagabo View Post
    Long GOPs (not necessarily lossy codecs) require a lot of work for random (or backward) seeks -- which is required by the Reverse() function.
    Well - yes, You are 100% right - long GOP instead lossy (albeit mostly long GOP's are also lossy - from non lossy and computationally intense i can imagine only FFV1)
    I knew you were aware of that. I just wanted to clarify for the OP.
    Quote Quote  



Similar Threads