Revise transcode_aac example and various updates
#393
| Job | Run time |
|---|---|
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| 1m 13s | |
| 6m 5s | |
| 6m 32s | |
| 27m 16s | |
| 1h 3m 46s | |
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| 12s | |
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| 46s | |
| 4s | |
| 2m 12s | |
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| 2h 13m 51s |