[FFmpeg-user] Constant 't' not working inside filter chain

Stefano Sabatini stefasab at gmail.com
Mon Jun 25 15:01:54 CEST 2012

On date Friday 2012-06-22 14:21:28 +0530, Murthy avsn encoded:
> Hi all,
> I suing a filter chain to zoom in  overlay video slowly .I am using the following command
> ffplay -i f1.mp4 -vf  "[in]split[one][two];[one]scale=iw-t:ih-t[scaled];[two][scaled]overlay=(W-w)/2:(H-h)/2" 
> Problem : I am getting an error  undefined constant t.
> Can some one please help me.

[src @ 0xb6600700] w:640 h:360 pixfmt:yuv420p tb:1/48 fr:0/0 sar:0/1 sws_param:[Parsed_scale_1 @ 0xb6601820] [Eval @ 0xad5fcc88] Undefined constant or missing '(' in 't'    Last message repeated 1 timesError when evaluating the expression 'ih-t'.Maybe the expression for out_w:'iw-t' or for out_h:'ih-t' is self-referencing.
[Parsed_scale_1 @ 0xb6601820] Failed to configure output pad on Parsed_scale_1   0.00

This means that the constant "t" is not supported in the scale
expression, check documentation.
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