Bitrate calculations (Mainconcept encoder settings help)

[indijay]

Hello All,

So far I was under sweet impression that I understand the bitrate calculations till I did some yesterday. I made my first DVD using Adobe Premiere Pro 2.0 It was one hour video using 4:3 PAL high Quality 7mbps CBR preset available in Mainconcept embedded in Premiere Pro 2.0 The output file is of size 3.7GB
When I did the calculations, in theory the size should be about 2.6GB (excluding audio) right? If its 7mbps then one minute is 420mb and 60 minutes is 2.52Gb and here I have file of 3.7GB so I am wondering if rest is the size is of 16bit PCM audio?

Secondly, if I wish to encode audio into ac3, how do I do it using same encoder in Premiere Pro 2.0?

Third, can anybody direct me to the link or literature where all these presets are explained? 4:3 PAL Higher Quality 4mbps VBR 2 pass and 4:3 PAL Lower Quality 4mbps VBR 2 pass doesn't make me understand much, if there is simple explanation more than higher and lower quality, would love to know rather than spending about 10 hours of CPU run...

Thanks a lot.

[Cornucopia]

7Mbps * 60sec/min * 60 min = 25,200Mb
* 1MB/8Mb = 3150MB
* 1GB/1024MB = 3.076GB

Plus audio:

PCM @ 48kHz...

2ch * 16bit/sample/channel * 48000 samples/second * 60 sec/min * 60 min = 5,529,600,000 bits
* 1MB/8Mb = 691,200,000Bytes
* 1kB/1024B = 675,000kB
* 1MB/1024kB = 659.18MB

Total: 3150 + 659 = 3809MB or 3.72GB

Looks like it's right on the money.

Don't know about AC3 encoder in PP2. I use SFSE or Vegas.

You can tweak those presets and keep your own copies. Try it and find out what you prefer.
Best thing is to export just a short ~2min. section.
Once you know how long it takes, and the kind of quality you find acceptable, that's the one to use--just extrapolate the time.

Scott

[indijay]

7Mbps * 60sec/min * 60 min = 25,200Mb
* 1MB/8Mb = 3150MB
* 1GB/1024MB = 3.076GB

Plus audio:

PCM @ 48kHz...

2ch * 16bit/sample/channel * 48000 samples/second * 60 sec/min * 60 min = 5,529,600,000 bits
* 1MB/8Mb = 691,200,000Bytes
* 1kB/1024B = 675,000kB
* 1MB/1024kB = 659.18MB

Total: 3150 + 659 = 3809MB or 3.72GB

Pardon my medical background but I understood only first line of audio and video. Is it possible for you to be didactic on second and third (and 4th of audio) line??

BTW, what is this SFSE?

Thanks

[Cornucopia]

7Mbps * 60sec/min * 60 min = 25,200Mb
* 1MB/8Mb = 3150MB
* 1GB/1024MB = 3.076GB

2ch * 16bit/sample/channel * 48000 samples/second * 60 sec/min * 60 min = 5,529,600,000 bits
* 1MB/8Mb = 691,200,000Bytes
* 1kB/1024B = 675,000kB
* 1MB/1024kB = 659.18MB

Total: 3150 + 659 = 3809MB or 3.72GB

Line1 Video filesize in Megabits.
Line2 Convert Bits to Bytes (1Byte = 8bits)
Line3 Convert Megabytes to Gigabytes (1024MB = 1GB)

Line4 Audio is stereo (2ch), 16bit, 48kHz, LPCM, so the bitrate is a direct product of those elements (that's the "linear" in LPCM). Audio filesize calculated like Video, but in bits.
Line5 Same conversion as Line2
Line6 Convert Bytes to kiloBytes (1kB = 1024B)
Line7 Convert kiloBytes to MegaBytes (1MB = 1024kB)

That's it. That way, they all are referred to using the same kind of units (MB, GB).

Scott


>>>>>>>>>
edit: SFSE is SonicFoundry Soft Encode (standalone AC3 encoder). Obsolete now, and basically incorporated into the AC3 encoding plugin of Vegas+DVDA, but still usable.

[indijay]

Thanks a lot, now picture seems very clear