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Jagged video edges problem - video for a website download

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peter dunphy
Jagged video edges problem - video for a website download
on Feb 5, 2012 at 12:48:13 pm

Hi Guys

If anyone here could offer any advice whatsoever on the below jagged video problem I'd really appreciate it. I'm at a bit of a loss as to how to solve it.

Here is a photo of the 'jagged' problem I'm seeing:

Client sent me an emailing saying: "I believe the video should have been interlaced before it was supplied to us. Interlaced footage is designed for web delivery; de-interlaced footage as seen here is only used for TV broadcast and DVDs."

The video was shot at 50i on a Canon XHA1 (PAL) in the UK then edited as standard ProRes 422, exported as self-contained Quicktime from FCP, then this was brought into MPEG Streamclip.

Using MPEG Streamclip I created a compressed MP4 with the following stream info:

Duration: 0:10:24
Data Size: 89.98 MB
Bit Rate: 1.21 Mbps

Video Tracks:
H.264, 640 × 360, 25 fps, 1.08 Mbps

Audio Tracks:
MPEG-4 Audio stereo, 48 kHz, 128 kbps

Under the MPEG Streamclip heading 'Deselect for progressive movies' I had 'Interlaced Scaling' ticked (yes), 'Reinterlace Chroma' ticked (yes, greyed out) and 'Deinterlace Video' not* ticked (no). Field Dominance was set to Upper Field First.

The result of this is that the video looks jagged, as per the photo.

By ticking 'Deinterlace Video' (Interlaced Scaling and Reinterlace Chroma greyed out and ticked) the 'jagged edges' seem to go away, as per the comparison in the photo:

Do you think I could submit this version to the client?

Any advice whatsoever would be massively helpful.

Peter Dunphy

2 x 2.66 GHz Quad-Core Intel Xeon, 8 GB 1066 MHz DDR3, ATI Radeon HD 4870, ATTO ExpressSAS R380, Sonnet D800 Raid 5

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Bill Hall
Re: Jagged video edges problem - video for a website download
on Feb 17, 2012 at 4:01:13 pm

Your client has the information backwards. Computer screens all display video progressively. All video for the web or to be viewed on a computer should be deinterlaced, that is to say it should have a progressive frame draw.

Interlaced footage is relegated to broadcast TV. Interlacing was actually a trick developed by broadcasters to save bandwith.

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