Recherche avancée

Sur d’autres sites (6184)

• avcodec/refstruct : Add RefStruct pool API

  5 août 2022, par Andreas Rheinhardt

  avcodec/refstruct : Add RefStruct pool API
  Very similar to the AVBufferPool API, but with some differences :
  
  1. Reusing an already existing entry does not incur an allocation
  
  at all any more (the AVBufferPool API needs to allocate an AVBufferRef).
  
  2. The tasks done while holding the lock are smaller ; e.g.
  
  allocating new entries is now performed without holding the lock.
  
  The same goes for freeing.
  
  3. The entries are freed as soon as possible (the AVBufferPool API
  
  frees them in two batches : The first in av_buffer_pool_uninit() and
  
  the second immediately before the pool is freed when the last
  
  outstanding entry is returned to the pool).
  
  4. The API is designed for objects and not naked buffers and
  
  therefore has a reset callback. This is called whenever an object
  
  is returned to the pool.
  
  5. Just like with the RefStruct API, custom allocators are not
  
  supported.
  (If desired, the FFRefStructPool struct itself could be made
  
  reference counted via the RefStruct API ; an FFRefStructPool
  
  would then be freed via ff_refstruct_unref().)
  Reviewed-by : Michael Niedermayer <michael@niedermayer.cc>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/refstruct.c
  • [DH] libavcodec/refstruct.h

• image sequence to Video. Faster Way to Render "Hold" frames in FFMPEG (without duplicating image)

  11 septembre 2014, par dprogramz

  I’m working on a project that converts a Flash Movie with dynamic input to Apple Animation Codec.

  It’s to generate messaging, so there is some animation, then the message holds, then animation resumes, etc. The hold times are user variable.

  I’m first converting the SWF to PNGs by sending a bitstream via the actionscript3 PNGEncoder library, and using a PHP script to save the bitstream to the server as a series of temp png files. This is working very fast.

  from flash ill get an image sequence like this :

  frame000.png-frame014.png

  frame0200.png-frame250.png

  frame350.png-frame400.png

  frames 15-199 are all the same image holding. I’m not sending bitstreams for the holding images to save bandwidth and time, it would be redundant to send the same image file 185 times. Right now I am copying frame14.png with incrementing file numbers. I have to do this for each instance there is a hold frame.

  After all the hold frame holes are filled I then run FFMPEG on the complete image sequence to generate the video.

  Is there any faster way to do this ? The longer the hold (which is variable by the user) the longer it takes to render. I understand that there will be some extra render time, but it’s a repeated image and in other conversion programs does not take nearly as long. Or is my current way of doing it the only way in this instance ?

  When rendering out of a program like after effects, the animation codec seems to dynamically adjust the frame rate for hold frames.

  Thanks for the help and insight !!

• ffmpeg and iis smooth streaming

  19 février 2015, par Andrey Pietrov

  I have a local iis instance with configured publishing point. The point is good I’ve tested it by Expression Encoder 4 Pro IIS smooth streaming feature.
  But when I’m trying to stream to is using ffmpeg, Silverlight player can`t play my stream - just buffering action in process. Here is my ffmpeg command

  ffmpeg -f dshow -i video="WebCam SC-13HDL11431N":audio="Microphone (Realtek High Definition Audio)" -movflags isml+frag_keyframe -threads 2 -c:a libvo_aacenc -c:v libx264 -preset fast -b:v 64k -bufsize 64k -flags +global_header -f ismv http://localhost/lf.isml/Streams(lf)

  Manifest file (http://localhost/lf.isml/manifest) is correct and available for Silverlight streaming but unfortunately player doesn’t play my stream.
  Any suggestion or help ? Maybe I’ve forgot some parameter in command ?