Question about minidv bitrate

[t-h-e-w-h-o]

I was just curious, i had been reading in allot of threads here that people should encode a 8,000 CBR when trying to go from minidv to DVD mpg2... It was to my understanding that mini-dv (unless sonys DVCAM) format was only around 4.5mb/sec or at max 6mb/sec (6,000) Just curious, because of what i listed is correct then encoding a MPG file from mini-dv source at 8,000 or 9,000 CBR (OR VBR) would be pointless.
Just trying to clarify that, thanks guys.

[jagabo]

The DVD bitrate you refer to is ~8 mega BITS per second. Mini DV is 3.6 mega BYTES per second, or about 29 mega BITS per second.

[takeshi]

Mb - mega bit
MB - mega byte

The capitalization in the abbreviation denotes the difference.

There are no hard and fast rules for encoding to DVD. 8Mbps is really just a guideline or starting point. Obviously, if you're trying to fit 2 hours on a single layer DVD-R you're going to have to adjust the bit rate to make it all fit...

[Treebeard]

For my minidv conversion i usually use around 4000-4500 using a resolution of 352x480. results are just fine for me.

[guns1inger]

Many variables

1. Did you use a tripod when shooting ?
Yes - lower the bitrate
No - raise the bitrate

2. Is there fast action ?
Yes - raise the bitrate
No - lower the bitrate

3. Is it mostly talking heads and little movement ?
Yes - lower the bitrate
No - raise the bitrate

4. Is it an even mix between talking heads and action ?
Yes - consider VBR encoding
No - consider CBR encoding

None of this is hard and fast, just guidelines. But is hows you that nothing is as straight forward as DV = CBR 8Mbps

[bits]

For miniDV video you want to keep, such as family video, I would use 7-8Mbps CBR with a good software mpeg encoder. Who knows, maybe someday you will want to view this video on a large screen TV.

[t-h-e-w-h-o]

thanks for the help guys, Technically, isnt VBR supposed to generate higher quality than CBR?

[edDV]

thanks for the help guys, Technically, isnt VBR supposed to generate higher quality than CBR?

Most people handhold their MiniDV camcorders so all shots have X-Y and rotational motion that makes compression difficult and results poor. This type of video needs high bitrate CBR.

If you use a tripod and practice pro technique for pans and zooms (slow, steady, single axis), then you can benefit from VBR but only if you want more compression than ~8500 CBR. With the latter type of shoot, you can squeeze more compression using VBR. Two pass VBR allows you to fit a specific average bitrate but doesn't add significant quality. It won't be better than high bitrate CBR.

[slacker]

From WIKIPEDIA.ORG...

DV uses DCT intraframe compression at a fixed bitrate of 25 megabits per second (25.146 Mbit/s), which, when added to the sound data (1.536 Mbit/s), the subcode data, error detection, and error correction (approx 8.7 Mbit/s) amounts in all to roughly 3.6 megabytes per second (approx 35.382 Mbit/s) or one Gigabyte every four minutes. At equal bitrates, DV performs somewhat better than the older MJPEG codec, and is comparable to intraframe MPEG-2. (Note that many MPEG-2 encoders for real-time acquisition applications do not use intraframe compression.)

For every hour of video, I keep...

1. 1 62m miniDV tape of polished video (edited and corrected)
2. 1 dvd disc using 8.500 mbps CBR video 0.448 mbps AC3 audio
3. 1 dvd disc using 8.000 mbps CBR video 1.536 mbps LPCM audio

Hopefully, I have all my bases covered...

Mark

[edDV]

That would give best results for DVD. If the audio is just from the camcorder mic, AC3 will be good enough. If you are using better mics and want top audio, make sure the camcorder is set for 16bit, 48Kb/s, 2 channel LPCM.

[t-h-e-w-h-o]

alright, thanks guys. I have a dvx100b and upper end audio equiptment. Untill now i havent gotten heavy into encoding.

[edDV]

The DVX-100B is a special case. The above applies plus much more since it can shoot 480p/24.

See
http://www.adamwilt.com/24p/

BYW: 24p needs a tripod or Steadycam.