Bitrate - 18Mbps or 25Mbps for HDV?
I'm preparing my first Blu-ray disc with Sony DVDA 5, the default template sets the bitrate to 18Mbps, HDV is 25Mbps, will I encounter any playback problems if I use 25Mbps?
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Are you encoding to H.264 or MPEG-2 for Blu-ray? Bit for bit, H.264 is more efficient than MPEG-2, meaning that at the same data rate, H.264 offers superior quality. At lower data rates, the difference will be very noticeable, while at high data rates, MPEG-2 can look excellent and the H.264 advantage is somewhat lost (H.264 takes much longer to encode, so is it worth the time??).
The Blu-ray spec will handle up to 40Mbps, so don't be afraid to crank up the data rate if you have room (the program is not too long to fit the disc at the chosen data rate). Keep in mind the law of diminishing returns though, will anyone notice a quality difference between H.264 at 20Mbps vs. 30Mbps? Back to the original question, no playback problems at 25Mbps, perfectly safe. Get yourself a ReWritable Blu-ray blank and encode some short samples using both MPEG-2 and H.264 at various rates and make your own visual tests to see how you want to proceed. Jeff Pulera Safe Harbor Computers Quote:
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Jeff thank you for response! I'm currently encoding to MPEG-2 (quite happy with reduced encoding time), that's why 18Mbps seemed rather low. I actually don't have a BD burner at the moment so can't do any of my own tests however have been editing/rendering/storing all my projects in HD for the last year, I want to prepair my projects for Blu-ray now so that when I get a burner and find some thermal printable discs that I can send them out.
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Bluray burners are relative inexpensive these days.
Newegg.com - LG Black 6X BD-R 2X BD-RE 16X DVD+R 6X BD-ROM 4MB Cache SATA Internal Blu-ray Burner 6X Blu-ray Disc Burner & HD DVD-ROM Drive Model GGW-H20L - Blu-Ray Burners I paid $340 for this thing a little over 1.5 yrs ago. |
At 18Mbps I would forget about MPEG2 and use AVC. Also note that if you are using HDV1080i it is 1440*1080 - a resolution that is only supported using AVC on BD. If you used MPEG2 you would have to upscale to 1920*1080 or go down to 1280*720. Have a look at Blu-ray Disc - Wikipedia, the free encyclopedia for supported formats. Hope this helps.
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you CAN, just the disc wont be a STANDARD Blu-ray disc.
of course many player will read and display fine. |
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And as the previous poster stated, it would be best to convert 1440x1080i HDV files to the 1920x1080i Blu-Ray MPEG2 format in the main Vegas program if you want self-mastered MPEG2 Blu-Ray discs that meet the official Blu-Ray standards. With the Blu-Ray template, only the video gets rendered, so you must also render the audio separately. Use the AC3 Pro encoder to render out the audio, using the "Default" template (with HDV-embedded audio, it's typically stereo, 48 kHz sampling rate and 384 Kbps--you should change the audio bitrate in the custom settings to 384 kbps since the default audio bitrate in stereo projects is only 192 kbps). If you forget this and used the AC3 Studio encoder, DVDA Pro will always recompress the audio if your project is a Blu-Ray project since the AC3 Studio encoder is meant to be used with DVD Architect Studio, whose most recent version still supports only standard-definition videos. |
Taky is correct. 1440x1080 is a supported resolution of Blu-ray, does not need nor benefit from upscaling to 1920x1080.
http://www.blu-raydisc.com/Assets/Do...2955-15269.pdf |
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In other words, unmodified 1440x1080 HDV (which uses the MPEG-2 codec) authored onto Blu-Ray disc is considered "nonstandard", which means that some Blu-Ray players will choke on such a disc even if they support BD-R or BD-RE media. |
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Some Blu-ray players will not play BD-R/RE, no matter it is encoded with. That's just a sad fact of Blu-ray. |
Oh, I see that the info has not been updated as frequently as I would have liked.
At one point, the official Blu-Ray spec also listed 1280x720p at 50 fps (PAL) or 59.94 fps (NTSC). If I went with the often-futzed-with info on Wikipedia, those frame rates would have been no longer supported--this would have limited all progressive-scan video frame rate support to a low 25 fps (PAL) or 23.976 fps (NTSC). |
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I will change the Wikipedia page as I am sure it is confusing many people. |
Thanks for the update, Nick.
Still, it does not change the fact that 25p and 30p are still not supported in Blu-ray at any resolution. At present, for optimal playback results, 25p and 30p have to be converted to 50i and 59.94i (or 50p and 59.94p at 1280x720), respectively, before being authored onto disc. |
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