Second Annual MSU MPEG-4 AVC/H.264 Video Codec Comparison

For professional users and codec authors

Second H.264/AVC comparison home page!

Part 3. “Best speed” preset

Preset “Best speed”

Main codecs’ objective in this mode is the fastest video compression with satisfactory quality. Therefore main graphs in this section are graphs that show compression speed.

Y-PSNR

However, let’s consider Y-PSNR graphs at first.

Speed/Quality Tradeoff

Here are the most important graphs for this preset. They show codec's work time (abscissa axis) and quality of sequence, compressed with it (axis of ordinates). If codec A is to the left of codec B and above it then codec A is better than codec B; if to the right and below it then on the contrary, codec B is better than codec A. In other cases nothing can be said about definite advantage of one's codec compared to another's.

Bit rates in cutlines inside this section are target bit rates (not real codec bit rates).

Sequence “susi”, Y-PSNR

Sequence “battle”, Y-PSNR

Bitrate handling

Consider graphs showing how accurately every codec kept requested bit rate. Grades on x-axis show target bitrates (point 0 is 100 kbps, point 9 - 2340 kbps). Grades on y-axis show how many times codec exceeded declared bit rate (real bit rate to predetermined bit rate ratio).

Conclusions:

• Situation here is similar to “Best Quality” preset - DivX keeps bit rate very bad, raising it too high on low bit rates.
• The best among H.264 codecs in bitrate handling is Fraunhofer IIS, as before.

Time

Now let’s consider graphs that show time spent for each video sequence encoding in “Best Speed” preset and average normalized time for this preset.

Conclusions:

• Absolute leader by speed is codec from ATI company. At the average, it worked several times faster than its nearest competitor - VSS codec. And at the same time it is not worst one by the quality, though it is one of trailing codecs.
• The slowest codec in this mode again is Fraunhofer IIS. It lags behind its nearest competitor more than 3 times.
• Encoding time for Fraunhofer IIS codec increases noticeably when bit rate is increased.