There is a lot to decode and re-encode so it will take time. The time varies with the machine's speed. Nothing has changed to reduce this since people first begin to do video work.
Except the question. The answers vary from short to long but not one answer has changed the time unless the OP changes the machine.
Bob
Why does encoding take so long with MKV files, using toast,
[ready to burn as dvd's] two films take about 36 hours to encode?

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