Visualize information exported by some codecs.
Some codecs can export information through frames using side-data or other means. For example, some MPEG based codecs export motion vectors through the export_mvs flag in the codec flags2 option.
The filter accepts the following option:
- mv
-
Set motion vectors to visualize.
Available flags for mv are:
- pf
-
forward predicted MVs of P-frames
- bf
-
forward predicted MVs of B-frames
- bb
-
backward predicted MVs of B-frames
- qp
-
Display quantization parameters using the chroma planes.
- mv_type, mvt
-
Set motion vectors type to visualize. Includes MVs from all frames unless specified by frame_type option.
Available flags for mv_type are:
- fp
-
forward predicted MVs
- bp
-
backward predicted MVs
- frame_type, ft
-
Set frame type to visualize motion vectors of.
Available flags for frame_type are:
- if
-
intra-coded frames (I-frames)
- pf
-
predicted frames (P-frames)
- bf
-
bi-directionally predicted frames (B-frames)
Examples
-
Visualize forward predicted MVs of all frames using ffplay:
ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv_type=fp
-
Visualize multi-directionals MVs of P and B-Frames using ffplay:
ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv=pf+bf+bb