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  • Revision 24fbfa42f1 : Require armv6/media when building armv7 When building with runtime cpu detect a

    29 juillet 2014, par Johann

    Changed Paths :
     Modify /build/make/rtcd.pl



    Require armv6/media when building armv7

    When building with runtime cpu detect assume that armv7 targets can be
    relied upon to have at least armv6 support. This may allow dead code
    detectors to remove some _c functions.

    Change-Id : Iaec4414011fcbbdf6f4ed0d90ef4a8fe8af540b5

  • can ffmpeg detect monochromatic parts of a video and conditionally set filter parameters accordingly

    15 juillet 2021, par Silentfury

    I have input videos that switch back and forth between coloured and monochrome/grey parts (frames that only contain luma information). Is there a way in ffmpeg to detect whether the current frame is coloured or monochrome and is it possible to use this information to change the parameters of a filter ?

    


    As an example I want to apply the mpdecimate filter and I want it to use a "hi" parameter of 50 (per pixel) for coloured frames and 20 for monochrome frames.

    


    So in pseudo code I want something something like

    


    -vf mpdecimate=hi=if(coloured,64*50,64*20)

    


    but obviously the "coloured" condition doesnt work that way.

    


    Is that somehow achievable ?

    


    PS :
Concernig the detection of monochrome frames I have identified two filters that have a related functionality but I am unable to use the information in another filter :

    


      

    • "geq" can get a good idea of frame colors using cbsum(x,y) and/or crsum(x,y)
    • 


    • "signalstats" can use the property "SATMAX" to tell about the color level of a frame
    • 


    


    Is there any way to use the resulting number of any of the two above filters in another filter ?

    


  • aacdec : Lower the number of frames required to detect ADTS

    11 mars 2014, par Martin Storsjö
    aacdec : Lower the number of frames required to detect ADTS
    

    For live audio streams, requiring 500 frames for a stream to
    be detected is a bit overkill.

    This allows live ADTS streams that don’t start nicely at
    a frame boundary to start up more quickly, e.g.
    http://mp3.streampower.be/radio1.aac.

    Signed-off-by : Martin Storsjö <martin@martin.st>

    • [DH] libavformat/aacdec.c