Changes between Version 5 and Version 6 of Debug/MacroblocksAndMotionVectors


Ignore:
Timestamp:
Jan 13, 2018, 3:23:49 PM (6 months ago)
Author:
Gyan
Comment:

shift obsolete sections to bottom - with avcodec major bump to 58, no longer available

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  • Debug/MacroblocksAndMotionVectors

    v5 v6  
    22 
    33You can use `ffmpeg` or `ffplay` to analyze the macroblocks / coding tree units and motion vectors in a video file.  
     4 
     5== Analyzing Motion Vectors == 
     6 
     7The [http://ffmpeg.org/ffmpeg-all.html#codecview `codecview` filter] can be used to show motion vectors as small arrows for each macroblock. It takes one option called `mv`, which specifies the type of motion vector to be drawn: 
     8 
     9* `pf` – forward predicted motion vectors of P pictures 
     10* `bf` – forward predicted motion vectors of B pictures 
     11* `bb` – backward predicted motion vectors of B pictures 
     12 
     13For example, you can use: 
     14{{{ 
     15ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv=pf+bf+bb 
     16ffmpeg -flags2 +export_mvs -i input.mp4 -vf codecview=mv=pf+bf+bb output.mp4 
     17}}} 
     18 
     19Example: 
     20 
     21[[Image(vismv_pf.png)]] 
     22 
     23Caveats:  
     24* Earlier versions of ffmpeg do not have this filter, but support the now deprecated `-vismv` option. 
     25* This option does not work for codecs which do not export motion vectors (most non-MPEG based codecs) 
     26 
     27 
     28---- 
     29 
     30 
     31'''The following sections apply to ffmpeg versions older than October 21 2017.'''  
    432 
    533== Analyzing Macroblock Types == 
     
    4270 
    4371[[Image(visqp.png)]] 
    44  
    45 == Analyzing Motion Vectors == 
    46  
    47 The [http://ffmpeg.org/ffmpeg-all.html#codecview `codecview` filter] can be used to show motion vectors as small arrows for each macroblock. It takes one option called `mv`, which specifies the type of motion vector to be drawn: 
    48  
    49 * `pf` – forward predicted motion vectors of P pictures 
    50 * `bf` – forward predicted motion vectors of B pictures 
    51 * `bb` – backward predicted motion vectors of B pictures 
    52  
    53 For example, you can use: 
    54 {{{ 
    55 ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv=pf+bf+bb 
    56 ffmpeg -flags2 +export_mvs -i input.mp4 -vf codecview=mv=pf+bf+bb output.mp4 
    57 }}} 
    58  
    59 Example: 
    60  
    61 [[Image(vismv_pf.png)]] 
    62  
    63 Caveats:  
    64 * Earlier versions of ffmpeg do not have this filter, but support the now deprecated `-vismv` option. 
    65 * This option does not work for codecs which do not export motion vectors (most non-MPEG based codecs)