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Video type and size for the web
What are the recommondations here?
neophyte




msg:3393362
 5:34 am on Jul 13, 2007 (gmt 0)

Hello All -

I've never put any video of any kind on my projects before, but now I've got a client who has a 3-minute movie of his resort that he would like to include on the site.

He's already got one edited version - 320x240 pix, .wmv, 8.34mb - but it's so small and grainy that's it's not a very impressive marketing tool.

So... he wants to have it re-optimized to a larger viewing area and asked me if I knew of any web video "size standards" that he could talk to the editor about.

As stated above, the current version has also been optimized/saved as a .wmv file and he's wondering if this is the best format to save the 2nd cut in. The current video is also playing at 368 k/bits per second (whatever that means) according to Windows media player.

I have NO experience with on-line video, so could someone please weigh-in with some recommendations on standard video sizes for web viewing and a cross-browser/cross-platform file type that I can pass onto this guy?

All assistance with this questions is GREATLY appreciated!

Neophyte

 

thecoalman




msg:3394406
 6:30 am on Jul 14, 2007 (gmt 0)

The kbps is the bitrate or the bandwidth used. For example your 3 minute 386kbps video will take someone on a 56kbps dial up connection roughly 25 minutes to download and view. Higher bitrates produce better quality video but also produce a larger file. The bitrate has to be adjusted to the codec and resolution you are using. Different codecs perform differently at different bitrates, e.g. WMV may be fine at 500kbps but the same video would have to be 2000kbps if you used MPEG1 to get comparable quality. Too little bitrate and you start to get macroblocking, too much and you're just making a bigger file with no benefit.

Having said that 368kbps should produce a very good video at that resolution using WMV, actually a very good video. Note that's the combined bitrate of the audio and the video. The first thing to check is that the audio isn't at some ridiculous amount, download Gspot (don't laugh) and open the file with it and check the audio bitrate. At most it should be 64kbps.

Other than that poor results can be from a variety of things.Poor input such as noisy video, reencoding from a already compressed file, not deinterlacing interlaced video before encoding... there's lots of reasons and anyone of them can produce poor results. Increasing the resolution or bitrate isn't necessarily going to fix any of these issues**. High quality input, proper preparation and optimizing the output settings is crucial.

As far as format WMV is going to provide the highest quality/lowest compression/most compatibility. There's other codecs like divx that most will argue will provide better quality at the same bitrate but these won't play on Windows machine with a out of the box installation. Flash is another alternative and lastly MPEG1 but as mentioned above this requires 4X the bitrate hence 4x the file size. MPEG1 is however the most cross platform compatible video, it will play on just about anything.

As far as a standard size that's relative to your audience, 500kbps is usually the max I'll use. That's generally within the reach of most on broadband unless there on a really slow DSL connection. I usually provide a much lower bitrate video for those on dial-up.

**Note that I'm not reffering to creating a new video from the source, increasing the resolution or bitrate of already encoded video has no benefit and will actually reduce the quality.

trooper27




msg:3396963
 1:21 pm on Jul 17, 2007 (gmt 0)

there ya go mate:

1)Image size 2)Frame rate 3)Aspect ratio 4)Display

NTSC - 1)720 x 480 - 2)29.97 - 3)D1 - 4)Interlaced

PAL - 1)720 x 576 - 2)25 3)D1 4)Interlaced

Computer - 1)Varies(much larger) 2)-- 3)Square 4)Progressive

thecoalman




msg:3397612
 1:01 am on Jul 18, 2007 (gmt 0)

NTSC - 1)720 x 480 - 2)29.97 - 3)D1 - 4)Interlaced

1) For both NTSC and PAL what you have listed are the max resolutions for DVD's. Or Full D-1 There are other valid resolutions. It's also the resolution mini-DV record in.

3) D1 is not an aspect, as mentioned it's in reference to the resolution. Note that resolution and aspect are two completely different animals and can be set independent of each other. 720x480 can be either 16:9 or 4:3, these are the only valid aspects for DVD. Sources wider than 16:9 have black bars added to the video file itself to maintain aspect.

As far as how this relates to video on the internet:

1) It can be anything but since your typical source is from a mini-DV cam which is 720x480(PAL576) you should use that or a lower resolution. Scaling video up provides no benefit and generally produces poor results. Instead let the player scale it.

2. Framerates can be changed but doing so incorrectly will produce choppy video. There is a benefit here, each frame requires X amount of bitrate. By reducing the framerate you can reduce the bitrate which results in a smaller file.

3. This is only applicable to video you're supplying a direct link to. Aspects can be set to whatever you want but whether its going to be respected by the player is another story. The best practice is to encode at a resolution that matches the aspect to insure the aspect is played back properly.

4 Most video cams record interlaced, there are some that record progressive. Each frame of video actually contains two frames split into fields. This looks great on TV designed to play it but not so great on a Computer. You can see this during fast motion particularly, it produces a stair-stepping affect. To combat this you can deinterlace the video but this is a destructive process. There are a few methods but the end result is you are throwing half the frame away.

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