ARCHOS AV300
Video Resolution FAQ
7/3/2003 v1.1

What settings should I use with DivX5.x to encode video for the AV300?

• If you are going for Maximum quality for TV-Out:
  1. Use the highest resolution the AV300 supports (see the offical and unoffical max resolutions in this faq)
  • For most movies this means use 640 for your width and scale your height appropriately. If you use the SmartResize filter in virtual dub you can select "fit width" and set the width to 640 - then the heigh will automatically be selected correctly. (see my JBM20 Virtual-Dub tutorial for more info)
  • For 4:3 ratio video (from TV or DVDs of TV shows), you'll have to find the best 4:3 ratio - see the unoffical max resolutions below
  2. Use 1500kbps for 1-pass encoding
  3. Use 1200kbps for 2-pass encoding
  4. For lower, but still acceptable quality, use 500kbps with 2-pass encoding (800kbps for 1 pass)
• If you want high quality video for use mainly on the AV300's LCD:
  1. Use 320x240 resolution
  2. Use 750kbps for 1-pass encoding
  3. Use 500kbps for 2-pass encoding
  4. For lower, but still acceptable quality, use 300kbps with 2-pass encoding (500kbps for 1 pass)
• Things to remember in either case:
  • The ratio of your Original Width to your New Width should be about the same as the your Original Height to your New Height:
    • (Original Width / New Width) = (Origonal Height / New Height)
  • The Width and Height must BOTH be multiples of 4
  • Always use the same FPS (Frames Per Second) as the source material:
    • NTSC is 30fps (USA TV)
    • PAL is 25fps (Europe TV)
    • Movies are 24fps

What are the max resolutions the AV300 can support?

Officially:

• 640x304@30fps
• 640x368@25fps
• 640x480@(low)fps

Unoffically:

The AV300 will attempt to play any Mpeg4 AVI that is 640x480 or less regardless of its FPS, however, if it can't keep up, the audio and video get out of sync and the video jumps randomly. Any resolution larger than 640x480 and the AV300 simply says: "Cannot play video data! Image size too big."

So, what are the max resolutions and frame rates that the AV300 can keep up with? To answer this question, I have to make some assumptions:

1. The max resolution is limited by the DSP speed
2. The DSP can only process so many pixels per second.
3. So, we can guess the DSP Pixel-Per-Second rating using the official max video resolutions:
   • 640 x 304 x 30 = 5,836,800pps
   • 640 x 368 x 25 = 5,888,000pps (I'll use this value)
4. The official max resolutions are at the lowest of the 3 DSP speeds:
   • 94.5mhz (Standard)
   • 99.0mhz (5%) (Overclock)
   • 108.0mhz (14% faster) (Overclock)

With these assumptions I have speculated the following theoretical max resolutions (remember, both the width and height must be multiples of 4 for Mpeg4 video):

What are Aspect Ratios?

• Someone else has already covered this better than I could - click here.

What is Full DVD resolution?

• For the NTSC standard (USA TV): 720x480@30fps
• For the PAL standard (Europe TV): 720x576@25fps
• Note: If you do the calculations, neither of these resolutions have an aspect ratio of 4:3, but NTSC and PAL both use the 4:3 aspect ratio. Why is this? It is because both of these resolutions use non-square pixels. In other words, the calculations for maintaining the correct aspect ratio are a little more complicated. Usually your DVD ripping software will take care of this automatically. (sorry to gloss over this, but it would take some time to explain)

Why do my AVIs not play fullscreen?

Only certain video resolutions will play full screen on the AV300.

• 640x480 is full screen - if your AVI is < 640x480 but > CIF, it will not play "full screen"
• 352x288 (cif) is full screen but cropped (it goes slight off the screen)
• 320x240 is full screen - if your AVI is < 320x240 it will not play "full screen"

-Shane Brinkman-Davis