Low Resolutions: Better With Slow Motion Codec!
Our test clearly establishes that if video sequences are prepared up to a resolution of 352 x 288 pixels (half PAL resolution), then the slow motion codec is definitely better suited! In this range, the video quality of the slow motion codec is better in spite of a lower data rate than with the fast motion codec with a higher data rate. The situation is completely different if the resolution exceeds 352 x 288 pixels. In this case, the fast motion codec should be used, irrespective of the film content (fast or slow movement). By way of a test sequence, we used the DVD video "The Jackal", which was coded up to 720 x 576 pixels with different resolutions. Especially with a full PAL resolution it was shown that the fast motion codec produces very good video pictures with a relatively low average data rate.
| Video Resolution | MPEG-4-Codec, Data Rate | Overall Data Rate | Quality | Length of Film on CD-R |
|---|---|---|---|---|
| 720 x 416 Pixels | Fast-Motion, max. 6000 kBit/s | 145 kB/s | very good | 83 min |
| 720 x 416 Pixels | Fast-Motion, max. 900 kBit/s | 128 kB/s | good | 94 min |
| 720 x 416 Pixels | Slow-Motion, max. 6000 kBit/s | 216 kB/s | very good | 55 min |
| 720 x 416 Pixels | Slow-Motion, max. 900 kBit/s | 128 kB/s | satisfactory | 94 min |
This table compares the two MPEG-4 codecs with a full PAL resolution. The slow motion codec produces a higher data rate with high resolutions than the fast motion codec.