Replace sws_scale with sws_scale_frame and enable multithreaded reformatting
#1251
| Job | Run time |
|---|---|
| 3m 15s | |
| 4m 36s | |
| 9m 17s | |
| 8m 46s | |
| 48s | |
| 8m 57s | |
| 35m 39s |