Computer Generated Video Sequence Compression

Created from the POV-Ray 3.5 sample scene found in /scenes/animations/slinky/slinky.pov rendered with 250 frames. The fast changing sequence was created with "clock" running from 0.0 to 1.0. The slowly changing sequence was created with "clock" running from 0.0 to 0.1. Both sequences were rendered with 720*576 pixels resolution and single-frame output. This is the DVD and DV resolution for PAL video. For NTSC video the resolution is 720*480 pixels but at 30 frames per second rather than 25 frames per second for the PAL video. All other settings were left at their default.

This demonstartes how an improperly created animation - with content that changes too fast - will bring any modern video compression method down. The reason is that all modern video compression methods heavily depend on being able to detect and encode how the content changes from one frame to the next. However, in real-world video very fast motion will still be limited by what appears a motion-blur, that is, each frame actually shows a short period of time when the photo material (be it a CCD or old-fashioned film) as it is exposed to light. The is not the case for a computer generated animation. Here the content can really jump from one frame to the next. Hence, an animation rendered without motion blur (not possible in any official version of POV-Ray) will not compress well with any modern video compression method if its frames change too much. This has to be remembered when comparing video codecs.

It should be noted that ancient video compression methods do not support advanced compression features and hence tend to not be affected by such problems. However, they are unsuitable for high-resolution video. They were never meant to be used for much more than 160*120 pixel movies.

Fast Changing Video Sequence

MPEG-2

Both created with ffmpeg from the maximum quality Motion-JPEG version (see below). 12 MBit is little bit more than the maximum found on a DVD (maximum on a DVD is about 10 MBit). 24 MBit is a much higher data rate than can be used on a standard-compliant DVD.

12 MBit PAL 14.3 MB (Download - mpeg2-12mbit.m2v)

24 MBit PAL 28.6 MB (Download - mpeg2-24mbit.m2v)

MPEG-4

Both created with the QuickTime 6.3 ISO-compliant MPEG-4 codec.

2 MBit 1/4 PAL 2.4 MB (Download - mpeg4-360*288-2mbit.mp4)

2 MBit PAL 2.4 MB (Download - mpeg4-720x576-2mbit.mp4)

Divx

Created using Divx 5.0.5 codec for QuickTime. Maximum bitrate allowed by the configuration dialog. Command-line that supposedly reproduces this is "-bv1 8000 -psy 1 -key 50 -p -sc 50 -pq 5 -vbv 8000000,6291456,4718592 -profile 4".

8 MBit PAL 8.2 MB (Download - qt-divx-hq.avi)

DV

Format used by digital video cameras. This is a lossy YUV 4:2:0 format (for PAL DV) with a fixed 25 MBit/s data rate. Every frame is encoded separately. Consequently, the result is independent of frame-to-frame differences. Encoded with the QuickTime 6.3 software DV codec.

PAL 34.3 MB (Download - dv-pal.dv)

Motion-JPEG

Common Motion-JPEG with maximum quality setting in QuickTime. Can easily be created from the lossless QuickTime PNG image sequence.

Over 125 MB (not available for download!)

QuickTime PNG Image Sequence

Lossless PNG images as a sequence with a 25 hz frame rate used as source for all other versions.

PAL 46.6 MB (Download - qt-png-lossless.mov)

Slowly Changing Video Sequence