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Max Pre encoded H264 Minutes on a 25GB Bluray?
Jeff’s answer to me in another thread regarding maximum bitrate for a DVD intrigued me greatly…
In another post, he commented that a generic bitrate caclulation for DVD Bitrate, when you are doing Pre-Encoding for MPEG2-DVD for import into Encore would be: 560/Minutes=Maximum Bitrate…
I’ve been thinking about a similar equation that could be used for Single Sided (25GB) Bluerays, but alter the equation such that Maximum Time of project at 40Mb/sec of H264 pre-encode is the result….
So, if BluRay’s are 25GB space, and video is pre imported to Encore to H264 encoded at 40Mb/sec (The Bitrate)… would the resulting Equation for maximum amount of time that could imported to Encore pre-encoded to H264 @ 40Mb/sec without forcing Encore to do a re-encode would then be:
25GB(Size of BR Disk)/2400(at 40Mb/sec H264 bitrate* 60 Seconds-one minute)=Maximum Minutes of H264 @ 40Mb/sec without forcing Encore to do a second encode?
Is my logic correct?
Looking for 1939 Indian Motocycle
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2 Replies
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Don’t overthink it, just use the calculator – https://dvd-hq.info/bitrate_calculator.php
Also, do yourself a favor and forget about the 40mbps max. Don’t go there! First off, you will probably find that 25mbps looks fantastic. Go 30mbps if it makes you happy. But keep in mind that store-bought DVDs and Blu-ray discs are stamped/pressed from a mold. The pits are physically pressed right into the disc surface.
You and I are burning the pits with a laser beam, on entirely different media, so when really pushing the data rate one is more likely to get playback/compatibility errors. DVD and Blu-ray players are not required to play burned media, it’s just a bonus that it works at all. Use high-end media and don’t push the data rate for best results.
Regarding the calculator for BD, use the BD-SL presets. Set audio at 384kbps (Dolby rate). For 120 minutes, the 25mbps average for video is good. I have put longer videos on Blu-ray, like 2.5 hours, and still looked very good using lower bitrate. Remember that H.264 is more efficient than MPEG-2, so can provide good results at bitrates that would not look as good with MPEG-2.
Thanks
Jeff Pulera
Safe Harbor Computers -
As usual, Thanks for your reply…
Once I compared 15Mb/sec to 40Mb/sec H264 on Blue-Ray using same project…. And I did notice more aliasing on the video with lower bandwidth… So I went to 40 and stayed there.
I’ve not encountered any failures of 40Mb/sec H264 yet… Say compared to DVD’s at higher bandwidth… (Which I encountered in great amounts years ago…. be it hardware firmware, Media quality or Read/Write speed.
In a web conversation it was inferred that pretty much anyone could put on a DVD Label on a player/burner hardware, but Blue-Ray label inferred a test to be qualified to wear the BRay Label… And that may have attested to the fact I wasn’t seeing as many failures on burned media with BR, vs. what I encountered ‘early on’ with DVD’s…Looking for 1939 Indian Motocycle
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