Revise transcode_aac example and various updates
#394
| Job | Run time |
|---|---|
| 5m 9s | |
| 23s | |
| 7m 30s | |
| 25s | |
| 5m 36s | |
| 5s | |
| 5m 41s | |
| 1m 6s | |
| 27m 2s | |
| 1h 3m 31s | |
| 6m 9s | |
| 6m 56s | |
| 3m 54s | |
| 3m 2s | |
| 2h 16m 29s |