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Old November 1st, 2005, 03:34 PM   #1
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HDV1 - why not 25 Mbps?

Does somebody know, why HDV1 720p uses only 19 Mbps? Would it not have been better to use 25 Mbps and to shorten the GOP? And what is the difference between Transport Stream and Packetized Elementary Stream?
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Old November 1st, 2005, 06:05 PM   #2
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The older JVC cams are fully compatable with DVHS and are below the broadcast stream maximum of 19.3 Mb/s. That's the only reason I can see. If I have read some posts correctly, the Sony cams cannot make a direct firewire copy to DVHS like JVCs.
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Old November 2nd, 2005, 02:23 PM   #3
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I believe the total bandwidth is 25mbps, including audio. So 19mbps for video, 6mbps for audio...?

Steve Mullen would probably be the one to answer this...
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Old November 2nd, 2005, 03:55 PM   #4
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The bandwidth of DVHS is 28.2 Mbps, not 19.3...

SONY probably just booby-trapped their cameras.
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Old November 3rd, 2005, 03:32 AM   #5
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The other potential reason is that 19mb/s on the same area of tape gives you a wider track pitch and therefore less chance of droputs.

Same reason Sony elected a higher tape speed for DV-Cam
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Old November 4th, 2005, 07:04 AM   #6
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The answer to this appeared on this forum ages ago... so a search may not find it for you!

The 19.3Mbit 720p data rate was based on the maximum Broadcast HD bit-rate.

The 25Mbit data rate was based on the maximum data capacity of Mini-DV tape.

Just a difference in philosophy, rather than some exotic conspiracy by megalomaniac corporate executives!!
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Old November 6th, 2005, 03:28 PM   #7
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Quote:
Originally Posted by Matt Irwin
6mbps for audio...
Does it capture 10 tracks of 5.1 audio??? :)
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Old November 7th, 2005, 01:11 AM   #8
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"The 19.3Mbit 720p data rate was based on the maximum Broadcast HD bit-rate."
What? Any link to that?

19.3Mb/s plus two channels PCM audio.
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