Media encoding and editing
x264 HD benchmark
This benchmark tests performance with one of the most popular H.264 video encoders, the open-source x264. The results come in two parts, for the two passes the encoder makes through the video file. I've chosen to report them separately, since that's typically how the results are reported in the public database of results for this benchmark. These scores come from the newer, faster version 0.59.819 of the x264 executable.
The Core i7 chips perform well enough during pass one, but it's during pass two (which seems to use more threads) that they really shine.
Windows Media Encoder x64shine Edition video encoding
Windows Media Encoder is one of the few popular video encoding tools that uses four threads to take advantage of quad-core systems, and it comes in a 64-bit version. Unfortunately, it doesn't appear to use more than four threads, even on an eight-core system. For this test, I asked Windows Media Encoder to transcode a 153MB 1080-line widescreen video into a 720-line WMV using its built-in DVD/Hardware profile. Because the default "High definition quality audio" codec threw some errors in Windows Vista, I instead used the "Multichannel audio" codec. Both audio codecs have a variable bitrate peak of 192Kbps.
The Core i7 delivers a bit of a clock-for-clock performance gain over the Core 2 here, even though it's handicapped by the fact that the app only uses four threads.
Windows Media Encoder video encoding
Roxio VideoWave Movie Creator
Make of these two WorldBench tests what you will. I prefer our other video encoding benchmarks instead.
LAME MT audio encoding
LAME MT is a multithreaded version of the LAME MP3 encoder. LAME MT was created as a demonstration of the benefits of multithreading specifically on a Hyper-Threaded CPU like the Pentium 4. Of course, multithreading works even better on multi-core processors. You can download a paper (in Word format) describing the programming effort.
Rather than run multiple parallel threads, LAME MT runs the MP3 encoder's psycho-acoustic analysis function on a separate thread from the rest of the encoder using simple linear pipelining. That is, the psycho-acoustic analysis happens one frame ahead of everything else, and its results are buffered for later use by the second thread. That means this test won't really use more than two CPU cores.
We have results for two different 64-bit versions of LAME MT from different compilers, one from Microsoft and one from Intel, doing two different types of encoding, variable bit rate and constant bit rate. We are encoding a massive 10-minute, 6-second 101MB WAV file here.
No real performance gains to report here.