AMV video format
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AMV is a video file format, produced for use in Chinese MP3/MP4/MTV Players; classified as S1 MP3 Players. Note that despite the word "MP4" in the description of several players, this is not an MP4 file format.
Video compression ratio is low, compared with other formats, though as the files are of low resolution and frame rate, file sizes are small compared to DVD/VCD/etc. (in a bytes-per-minute sense). Encoding and decoding are less processor-intensive than other contemporary formats (i.e. faster to encode on, say, desktop computer, and less hard on the batteries of the portable device), as in fact very little "encoding" is actually done.
For example (using typical values/approximations):
(note: AMV calculations based on 30 minutes at 128 x 96 pixels, 12 frame/s, 22050 sample/s mono sound : 80 MB (approx) The audio is 22050 sample/s, mono, MP3(?) - a safe guess would be a maximum of 10 MB being audio, yielding 70 MB for video, or approximately 40,000 bytes per second.)
| file | Approx. data rate | Resolution (pixels) | Frame rate | Pixels per second | Pixels per byte |
|---|---|---|---|---|---|
| AMV | 40,000 B/s | 128 x 96 = 12,288 | 12 fps | 147,456 | ~3.5 |
| DVD (MPEG2-PAL) | > 1,000,000 B/s | 704 x 576 = ~400,000 | 25 fps | ~10,000,000 | ~10 |
Software available (to date April 1st 2007) currently give screen sizes of 94x64, 128x96, 128x128 and 160x120, typically set to frame rates of 8, 12 and 16 frames per second (described as "low","medium" and "high"), which fits reasonably well on 1.2 to 1.5+ inch screens. By editing configuration files the range of frame rates handled by the encoder can be expanded to 8-24 (in 1fps increments), though using alternate framerates may cause problems if the player is not designed for those alternates.
There is also currently available a utility that will allow conversion between various other formats to AMV with screen settings, picture and audio quality. Other selections include the ability to 'zoom', (MODE in the programmers design terms). At present, there does not seem to be a utility that will convert AMV to any other format.
