[FFmpeg-user] Size of the video output file changes after mirror effect.

Lou Logan lou at lrcd.com
Tue Jun 12 01:00:24 EEST 2018

On Mon, Jun 11, 2018, at 10:17 AM, Mehta Naisargi Rajeshbhai wrote:
> Here size of video output file decreases after giving mirror effect. And 
> rest of the things remains same for example resolution remains the same. 
> So can anyone tell me that why the size of video output file is 
> changing?

Filtering requires encoding. The input is decoded, filtering is applied, then it is sent to the encoder to create the output. Since the output is not the exact same data as the input, and due to the differences between formats and encoder implementations, the resulting file size will be different.

> And  what steps I need to follow for mirror effect to keep the size of 
> the output file  same as that of the input file.

Why do you want to keep the file size the same?

Mirror it using your player instead. For example:

ffplay -vf hflip input.mp4

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