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[drawRecords]

Hello,

Can anyone advise me on what to ask for when requesting content (Video, Animations etc).

Currently I ask for all footage to be supplied at 640x480 uncompressed .avi , .mpg, or .mov

I tend to sort out the footage in Final Cut Pro (adding effects, transitions or looping) then export as QT at 320x240 using Cinepak.

I use Arkaos and am about to get a new 800Mhz powerbook - will this run clips at 640x480?


thanks folks

jim

[fluchtpunkt]

using uncompressed files is an unnecessary waste of space.
with 640*480 @ 32bit color depth and 25fps the datarate is 30'000KByte/sec (~29MB/s or ~1.7GB/min)!!!!!!
if you really NEED your original sources free of any compression loss, you should at least run lossless compression algorithms over them: before saving the file select a lossless compression codec from the choices given or alternatively you can compress the file after saving (e.g. zip the file) - or you can do both (which may or may not yield additional size reduction).
i would not recommend you to keep losless copies of any animated content. consider: a video DVD usually provides (much) better quality than what a mixer or beamer can actually output (so we are actually storing 'too much' data on the DVD!). but with gigabytes a DVD stores hours - not just minutes - of video!
getting the compression right ( :confused: ) has a lot to do with having tried many times before, fiddling with the codec's & their setup - there is no simple rule. expect compression factors that still provide satisfactory output (whatever that means :) ) to vary from roughly 1/10 to 1/100. that's a lot of space saved - & even though harddisks are cheap it's still a lot of money saved!

cheers

[drawRecords]

cheers for the info - I am about to embark on a tour with a band and I have to liase with the guys who made the videos and EPK, live show film, etc so i need to give them the spec of how i want the source footage B4 I go to work on them - I would imagine i will be supplied it on CD-rom. Should i ask for the following?

640x480
lossless compression
32bit color depth
25fps
.avi


I would then size all clips to 320x240 and use cinepak compression

I will be projecting thro' Arkaos on powerbook at a screen size of approx 12 foot square

how does that sound?

cheers

[LEVLHED]

sounds like a good place to start, although you might want to define which "lossless compression" you want and the settings/etc....just to avoid any confusion.
But getting them @ 640x480 and then crunching them to your performance-size/codec is a good idea....

[fluchtpunkt]

Originally posted by drawRecords

640x480
lossless compression
32bit color depth
25fps
.avi

I would then size all clips to 320x240 and use cinepak compression


no, again don't keep losless copies! there's especially no point in saving lossless originals if the copies you will use will have half the resolution (= 4 times less space) and strong redundancies introduced (i.e. strong compression, ~10 to 100 times less space). so you're using 400 times the space you cold be (to keep the quality of the output) at worst and 40 times the space at best!
save the original, 640x480 with lossy compression (don't use cinepak if you can avoid it... mpg, divx,..., are better in most cases). change the settings to achieve a result you find satisfying (i.e. quality<->space consumed). emphasize quality.
do the same with the output files - with special consideration to the environment they will be used in. emphasize compatibility with user programm (-> quality in the app).

as a rule of thumb compressing to roughly one tenth (or more) the size of the uncompressed file will yield very good quality. there's no point in using less compression - you'd just be wasting space because the human mind (and especially in combination with the mixer & beamer...) doesn't notice the quality improvement any more!
most of the time you can compress a lot more than just 1tenth & still have satisfyable results!


i guess the numbers can be confusing if they're new to you :)

...

is there a post/article on the forums/vjc on compression & 'basic image properties'? does anybody know a good web resource?

[drawRecords]

coolio

thanks for the help guys

jim

[drawRecords]

Originally posted by fluchtpunkt
you should at least run lossless compression algorithms over them: before saving the file select a lossless compression codec from the choices given


thanks fluchtpunkt but i am a little confused you say in the quote above to use lossless compresion?

[LEVLHED]

fluchtpunkt, I think you're missing the particualrs of his situation... and why can't he keep copies of hi-rez clips on CDRs? He's not going to use them in his performance computer, he's getting them from someone else then he's compressing them...he wants to know whats the ideal format for him to get the clips from the other person....in that case, I'd get HI-REZ from them for any number of reasons (what if they want a DVD down the road?...OR a year from now he gets the latest computer that doesn't even flinch at the high rez clips?)
for the lossless codec, look into something like the midivid JPEG codec (www.midivid.com)

[fluchtpunkt]

Originally posted by fluchtpunkt
i would not recommend you to keep losless copies of any animated content.

...sorry i did write it in a confusing manner.
what i meant to say is that ( :) if your mad enough to keep lossless copies :) ) you should at least run ...etc.

[fluchtpunkt]

Originally posted by LEVLHED
... and why can't he keep copies of hi-rez clips on CDRs?

of course! don't get me wrong, i'm no enemy of hi-rez (on the contrary)!
but even if you're a complete hi-rez junk you're not best of with no or lossless compression! why? because the same clip consuming the same amount of space will be displayable in higher resolution if compression is used!
video-compression algorithms are out of their infant years & anybody who wants optimal quality with limited resources (& that is everyone) will not get around using them.
DVD itself is compressed to roughly 1/10 the original size.
...
if you want to use a lot of space for video use higher resolutions or color depth, don't save uncompressed video :confused:

----

btw uncompressed hi-rez e.g. 800*600*16 uncompressed means 30seconds per CD!

[drawRecords]

LEVLHED is correct, im more interested in getting the best source files.

so to re-cap what should i be asking for?

[robotfunk]

for the lossless codec, look into something like the midivid JPEG codec (www.midivid.com)

how is JPEG lossless? i do agree its a very good codec to use ie fast and good looking .. but losless it aint

[eXhale]

MidiVid has been designed for performances/playing, I doubt it's the best format for storing.

If you have a DV camera, get the videos in DV tapes, it's compressed at 1/4 (I think) and it will be easy to convert them to "playable" formats later. Much better than dealing with really huge video files.

[LEVLHED]

robotfunk...technically ANY codec isn't really lossless.
IF you think JPEG isn't up to snuff, then what would you reccomend?

eX, I'm talking about their JPEG codec, not the midivid performance codec

[drawRecords]

ok - it seems to be a can of worms this 'what compression' question. As i will be using a Mac for the editing and performance i guess that the Midivid one is out of the question?

What i really want is your opinions of how you would ask a production company (the guys who make the music videos) for the footage you would then use to put together a show that will be projected behind the band. I agree that DV is an option but i would prefer to be able to store everything on CDs (or DVDroms)

[MoRpH]

Yes there are lossless compressions, anything that uses runlength encoding for example, for both still and moving graphics, also I'm pretty sure MIDIVID has a lossless codec (switch/option) for achiving of material in highest possible quality.

As you are on mac, midivid is prolly out, so I suggest you do some research on current QT codecs and find something that is specifically lossles

[fluchtpunkt]

Originally posted by drawRecords

so to re-cap what should i be asking for?

...i guess there's no sense in arguing, i'll just give you the formula & you can work things out yourself.

uncompressed file size:

horizontalDimension * verticalDimension * colorDepth * frameRate * clipTime

-> x * y * RGB(A) * framesPerSecond * seconds

(A stands for an optional 'alpha' channel that usually controls transparency)

e.g.:

800pixel*600pixel*32bit*25fps*30s = 1.152*10^10bit = ... = 1.3411GByte

(1Byte = 8bit, 1KByte = 1024Byte, 1MByte = ...etc)

file size with compression:

((horizontalDimension * verticalDimension * colorDepth * frameRate * clipTime) / losslessCompressionRate) / lossyCompressionRate



imho compressing the source down to a factor of roughly one tenth (or 1/5 or 1/20 ... it all depends on the source&codec&output) will not cause perceivable deteriorisation. additional space is better used by storing in higher resolution.

[Primebase3]

DV for storing and Sorenson for performing (mac) ..just off the top of my head. (not sure)

[drawRecords]

bloody hell fluchtpunkt! im not sure what it means or what use it is but thanks.

Primebase3 has the right idea (something i can understand!)

cheers to all

[eXhale]

Originally posted by drawRecords
bloody hell fluchtpunkt! im not sure what it means or what use it is but thanks.It means that without compression 1.3Gb is used for every 30 seconds which would be a mess to deal with (even one DVDrom would not be enough for all the footage), so you better compress it a bit. Lossless compression isn't required, as it has been pointed out even DVDs are compressed in MPEG2 and it's top quality (not to mention DivX which does an even better job).

[fluchtpunkt]

Originally posted by drawRecords
bloody hell fluchtpunkt! im not sure what it means or what use it is but thanks.

:) :confused: :)

800pixel*600pixel*32bit*25fps*30s = 1.152*10^10bit = ... = 1.3411GByte

800pixel: number of horizontal pixels
600pixel: number of vertical pixels
32bit : 32bit color depth i.e. there are 8bit (or 256 values) for each of the channels R(ed)G(reen)B(lue)A(lpha), which results in ~17million different colors. alpha is usually used for transparency (...). other common color depths are/were 16bit (65'536colors), 8bit (256colors), 4bit(16colors), 2bit(4colors), 1bit(2colors, black/white).
25fps : frames per second, 25 in this case.
30s : the clip has 30 seconds duration.

... you multiply the numbers: 800*600*32*25*30 = 11'520'000'000bit (or 1.152*10^10bit)

1 Byte is 8 bits, 1 kiloByte is 1024 Bytes, 1 megaByte is 1024 kiloBytes & 1 gigaByte is 1024 megaBytes. divide the above result:

((((11'520'000'000/8)/1024)/1024)/1024 = 1.3411 gigaBytes

...

[many2]

DivX 5.x gets the job done of keeping mostly perfect sources at a much lower filesize. Usually I set it to encode in 1-pass quality based at 100%quality, set the keyframe interval to 1 frame and the VBE quantizer to min:2 max:2. It does not work so well for editing in Premiere for example as the codec has to read a loop from the beginning to access any frame.

[drawRecords]

thanks guys i apreciate the help

the problem ive had is having to re-request footage as the original supplied has been such low res and quality - film/video production companies tend to think that as im using a computer to play the footage it should be optimised for the web or something!

thanks again