Hugeeee File

dabear · Post by **dabear** » Fri Sep 28, 2007 2:21 am

I was working on this lil video while using msp 8.0

And the thing was about 4mins long and came out to 209mb mpeg.

How can i drop this file size to under 100mb with out losing much detail/sound quality.

troppo · Post by **troppo** » Fri Sep 28, 2007 7:17 am

reduce frame size
reduce bit rate
reduce frame rate

Gra · Post by **Gra** » Fri Sep 28, 2007 9:38 am

Hi Dabear

Are you preparing a movie for somewhere like You Tube? If so the link below to one of Steve's tutorials may be helpful:

http://phpbb.ulead.com.tw/EN/viewtopic.php?t=21263

Hope this helps.

Gorf · Post by **Gorf** » Fri Sep 28, 2007 9:46 am

A 4min vid of 209MB has a bitrate of about 7mbps. That's suspiciously close to DVD rates.

You want to drop the filesize: there are only two ways to do that: Edit stuff out or drop the bitrate. If you want 4min to come in at less than 100MB you'll need to drop the bitrate to 3.33mbps.

Depending on your video's content, you may just get away with using that bitrate on MPEG-2 at two-pass VBR. If not, and if you're not fussy about only having the computer* to play your video, one of the newer codecs like DivX will allow you to drop well below that rate, while keeping the frame rate and frame dimensions, and no noticeable loss of quality.

Reducing your frame rate and frame size do result in a loss of quality, how could they not? However, you need to weigh up how the resulting loss compares with dropping the bitrate or changing the codec entirely.

* Some set-top DVD players do support DivX, WMV etc.

dabear · Post by **dabear** » Sun Sep 30, 2007 5:47 pm

PocketDivXEncode

i found this encoding program and it did the trick.

dabear · Post by **dabear** » Tue Oct 09, 2007 3:23 am

troppo wrote:reduce frame size
reduce bit rate
reduce frame rate

how do i do this, like step by step,

I shouldn't have jumped at something else when i could use ulead to encode right. Give it a shot at least.

troppo · Post by **troppo** » Tue Oct 09, 2007 2:50 pm

It depends. Do you want to keep it as a MPEG file?
WMV files tend to be more flexible with regards to these parameters.

dabear · Post by **dabear** » Wed Oct 10, 2007 2:09 am

troppo wrote:It depends. Do you want to keep it as a MPEG file?
WMV files tend to be more flexible with regards to these parameters.

could you tell me both ways for mpegs and wmv files? I will try both ways to see which is best

troppo · Post by **troppo** » Wed Oct 10, 2007 3:16 am

You will find all these settings in the 'options' part of the the create video dialog box. Just experiment with the different settings till you are happy. If you are creating a WMV file there are heaps of presets to choose from, saving you the work.
I would only recommend exporting to an MPEG file if your ultimate destination is DVD, in which case you wouldn't want to reduce frame rate, or frame size.
Enjoy!

dabear · Post by **dabear** » Wed Oct 10, 2007 4:07 am

I dropped the file size by like from 210mb to 128mb but is still to big to upload anywhere. I think i figured it out tho going to keep trying thanks.

Gorf · Post by **Gorf** » Wed Oct 10, 2007 9:52 am

dabear wrote:I dropped the file size by like from 210mb to 128mb but is still to big to upload anywhere...

The only two ways to reduce the filesize are:

Edit stuff out
Reduce the bitrate

That's it.

Nothing else.

troppo · Post by **troppo** » Thu Oct 11, 2007 2:03 am

I disagree. I have reduced some files for email considerably by reducing the frame rate. (Less frames per second means less data, which means smaller file size) A similar principle is at work when you reduce frame size, less data, smaller file.
Otherwise wouldn't my mobile phone record at full frame rate and full size instead of 15fps and 320X240?

Gorf · Post by **Gorf** » Thu Oct 11, 2007 10:34 am

Disagree all you want - one of us needs to be wrong.

What filesize would a two minute 720x576 25fps MPEG running at 2mbps be?

What filesize would a two minute 320x288 15fps Cinepac AVI running at 2mbps be?

The answer to both is 30MB. To change the filesize, you need to change the duration or the bitrate.

Just to reinforce my point - imagine I have a clip at 768x512, 60fps with 16 bits per channel and encoded using DivX. How big is the file? You don't know, because I haven't given you the two pieces of information that will let you work it out. Even if I gave just one, you'd still be stuck.

If I go on to tell you it's 30 seconds long encoded at 5mbps, you can work it out easily, and you don't use a single item of information given in the above paragraph.

Your mobile phone probably can record at 30fps 640x480 (mine can). If it did so at the same bitrate as the 15fps QVGA setting, it would look awful, but the filesize will be the same.

Bitrate & duration affect filesize.
Bitrate, framesize, fps and codec affect quality.
You can adjust bitrate, framesize, fps and codec to try to maintain quality, but ultimately it's bitrate that will get the OP under his 100MB limit.

Devil · Post by **Devil** » Thu Oct 11, 2007 12:34 pm

Gorf wrote: What filesize would a two minute 720x576 25fps MPEG running at 2mbps be?

What filesize would a two minute 320x288 15fps Cinepac AVI running at 2mbps be?

The answer to both is 30MB. To change the filesize, you need to change the duration or the bitrate.

Not necessarily true. There are many things embedded into files that have nothing to do with the bitrate.

Let me put it this way, you have a 30 Mb file containing 2 minutes of MPEG-2. What is the video bitrate? 2 Mbit/s? WRONG:

1. Is it low level, main level, high 1440 level or high level?
2. Which profile/I/P/B frame macroblocks are used?
3. What is the GOP?
4. What quantisation is used
5. What audio layers are used?
6. Which audio encoding is used?
7. What is the audio bitrate?
8. Is motion compensation used?
9. Who makes the encoder (algorithms change with the maker)?

This is a tiny part of the data transmitted with a MPEG-2 video stream, large amounts of which are optional. Each GOP, as well as the whole file, has a header, each of which can contain literally hundreds of items of information, as well as the video and audio data. Each item may be just 1 bit long but many of them are several bits long, or even many bytes. These have to tell the decoder whether it is, e.g., NTSC or PAL, 4:3 or 16:9, 4:2:0 or 4:2:2 colourspace, the GOP structure, as well as hundreds of other pieces of information. It is impossible to know easily the proportion of the overheads to the actual video.

The corollary is that it is impossible to know the overheads, knowing the video bitrate and how they are multiplexed, unless you know exactly the encoding algorithms. Put it another way: if you encode exactly the same clip with three different encoders at the same constant bitrate, you will obtain three different file lengths and they can vary quite considerably.

Analogical considerations apply to all digital video formats, as they all have additional variable data embedded in the blocks. It is impossible to be categorical as to file length v. quality for a given duration and bitrate.

BTW, did you know that even CBR varies in both bitrate and quantisation? Not much, but the bitrate is typically ¡Ó5-10%.

However, this does not answer the OPs dilemma. I must admit I don't understand the problem. I presume he wants to upload his video to YouTube or similar, with a 10 min/100 Mb limit. I find that it is simple and I've described my OM before on this forum, such as at http://phpbb.ulead.com.tw/EN/viewtopic.php?t=26405 and elsewhere. Many who have viewed this unedited clip have been surprised at the quality from this simple method, which is ideal for MSP8.

troppo · Post by **troppo** » Fri Oct 12, 2007 6:00 am

Hi Gorf, I understand your point. I guess what I meant, is that by reducing the frame rate and frame size, you can also then reduce the bitrate without affecting quality too much. These 3 things should all be reduced together to find a happy medium between quality and file size.
To illustrate my point, in MSP8, if you increase frame size in the MPEG encoder options dialog, then it automatically increases the bitrate, to keep quality high.
So while your statement is true according to the letter of law, I think, for the sake of dabear's question, he will get a better quality result to reduce all 3.