Please add new feature to BATCH edit.
i have 6238 files , and i want to change the speed for that file.
reduce to 60% speed and 70% speed

Batch processing is done with “Macros”. See:

To change the speed, use the “Change Speed” effect:

That will probably be too many to run in one go.

Test your macro on “batches” of one or two files. When it works the way that you want it to, try increasing the batch size to about 100 files, and if that works OK, try increasing it to 500 files. It may be possible to process larger batches, but some users report problems if they use batches much bigger than 500 files.