FYI: some encoding speed comparisons

[Frobozz]

While playing around with my different DVD authoring applications: Toast 6.11, iDVD 5 and CaptyDVD 2.2, I decided to test the comparative encoding speed.

I used an 18-minute DV clip and for simplicity used the internal hard drive on my 933 mhz G4 iBook (OS 10.4.1) for both reading and writing. I also used an MPEG 2 version of the same clip for an additional test. I used PCM audio and plain, non-motion menus for all. I'm also excluding the time it takes to write the disc image files after the encoding is done (which is about 5 minutes regardless of the software used).

Toast 6's standard quality encoded the DV to MPEG in 53 minutes and its high quality required 1 hour 41 minutes. The file sizes of the two encodings were nearly identical with a target bit rate of 8 mbps and size of 1.25 GB.

iDVD 5 required 1 hour 24 minutes for the encoding. The target bit rate was 7 mbps and the file was just under 1 GB. This was using iDVD's default settings. I don't use iDVD much and there may be settings that speed it up. Also, I believe it does background encoding while you fuss with the menus which shortens the perceived time for completing the encoding.

CaptyDVD 2 was within seconds of the time needed for Toast's standard quality. (There are a couple preferences that I checked for enhancing the encoding speed). When I encoded at 8 mbps the file was a few MB smaller than Toast's. When I encoded at 6 mbps the time was the same and the file size was only a few MB smaller than iDVD's 7 mbps encoding. It is apparent that iDVD must use a broader VBR to get its file size that low.

When using the MPEG source rather than DV, Toast required about three-and-a-half minutes before writing the disc image. CaptyDVD required about seven minutes (it writes the file twice). Of course, iDVD can't compete in this event.

What about picture quality? I looked at high motion frames from each encoding on my iBook's screen and they all looked alike to me. Apparently I'm better with a stop watch than with my eyes because they can't have the same picture quality.

In summary, with a 933 mhz G4 expect Toast to need 3 minutes for encoding each minute of DV video at standard quality, and about 25 seconds for each minute when the source is MPEG 2. iDVD needs nearly 5 minutes to encode each minute of video and doesn't encode shorter videos at as high a bit rate as does Toast. CaptyDVD is more like Toast for speed.

One more thing: What brought all this on is that pixela-1.com is selling something called the CaptyDVD speed-up kit for CaptyDVD 2 Lite. It claimed a 250% speed improvement. I figured that was bull, but bought it just to find out what difference it made. It updated my version of CaptyDVD 2.2.0 to 2.2.2 and changed a couple files in the package. The result: it took 1 minute longer to complete the encoding than my original version (may be caused by something else going on with the iBook at the time). I don't recommend that others purchase the speed up kit.

[thoughton]

Nice post Frobozz! I have some similar data on ffmpeg and mpeg2enc which I will dig up and post here when I get home.