PDA

View Full Version : Confused beginner's questions!


SammyRoss
10th April 2004, 12:42
1- I have a 1GB+ .mpg file, that, when being dropped on GSpot does not show any codec utilization. Does this mean it's not compressed?

2- Is MPEG-1 a compressed file format or not? Is it the same as VCDs?

3- Let's say I want to further compress this 1GB+ file to reduce it's size. In fact, let's say I have any file, compressed with any codec (DivX3 for instance), and I want to compress it with a different codec that I prefer.
a- What tool can I use to do this?
b- Do I always have to decompress the file to raw video first before I start encoding? Or does the encoder utilize the system codecs to decompress it on the fly?

Thank you.

bond
10th April 2004, 13:12
Originally posted by SammyRoss
[B]1- I have a 1GB+ .mpg file, that, when being dropped on GSpot does not show any codec utilization. Does this mean it's not compressed?gspot doesnt handle .mpg files!

2- Is MPEG-1 a compressed file format or not? Is it the same as VCDs?hum i am not the .mpg specialist, but afaik it can store both mpeg-1 and mpeg-2 streams
and yes, mpeg-1 is used on vcd, mpeg-2 on svcd/dvd

3- Let's say I want to further compress this 1GB+ file to reduce it's size. In fact, let's say I have any file, compressed with any codec (DivX3 for instance), and I want to compress it with a different codec that I prefer.
a- What tool can I use to do this?read the doom9 guides!
basically there are lots of tools which can do that
i would recommend you to create an avisynth script .avs where you decode the .mpg via mpeg2dec3 or mpegdecoder ( mpeg(2)source() )
avi files can be used via avisource()
as i said use search and read the guides to find out more about that

than you can load this .avs file into virtualdub and encode

b- Do I always have to decompress the file to raw video first before I start encoding? Or does the encoder utilize the system codecs to decompress it on the fly?the other codecs can be used

Tommy Carrot
10th April 2004, 13:22
If the source is mpeg1, i dont see any need to use avisynth, just open the file with virtualdub.

SeeMoreDigital
10th April 2004, 13:35
Originally posted by SammyRoss
1- I have a 1GB+ .mpg file, that, when being dropped on GSpot does not show any codec utilization. Does this mean it's not compressed? If you want to check you .mpg files, then for the time being use VideoToolBox (http://www.kcsoftwares.com/?kmp3) from KC Softwares. I say for the time being because the maker of Gspot is intending to release a new version of Gspot that can read Mpeg1 and 2 streams!

Originally posted by SammyRoss
2- Is MPEG-1 a compressed file format or not? Is it the same as VCDs? Yes, Mpeg1 is a compressed file format (so is Mpeg2) However, when making an VCD, Mpeg1 is encoded at around 1100kbps and uses 240 vertical pixels (for NTSC) or 288 vertical pixels (for PAL). And both the audio and video stream is packed/authored into an .dat container.

Originally posted by SammyRoss
3- Let's say I want to further compress this 1GB+ file to reduce it's size. In fact, let's say I have any file, compressed with any codec (DivX3 for instance), and I want to compress it with a different codec that I prefer.
a- What tool can I use to do this?
b- Do I always have to decompress the file to raw video first before I start encoding? Or does the encoder utilize the system codecs to decompress it on the fly? In answer to 'a' - I use MPEGmediator, as you can (technically) use it to input Mpeg1 and 2 streams at the same time!

In answer to 'b' - It all depends on the encoding application. MPEGmediator will also let you import Mpeg1 or 2 files that contain audio

Cheers

EDIT: I forgot to mention. You might be interested to know that Mpeg1 can look every bit as good as Mpeg2 when encoded at so called 'DVD' bitrates (4000 - 6500+) and when using 480 vertical pixels (for NTSC) or 576 vertical pixels (for PAL).

Soulhunter
10th April 2004, 18:31
Originally posted by SeeMoreDigital
EDIT: I forgot to mention. You might be interested to know that Mpeg1 can look every bit as good as Mpeg2 when encoded at so called 'DVD' bitrates (4000 - 6500+) and when using 480 vertical pixels (for NTSC) or 576 vertical pixels (for PAL). Hmm, IMHO MPEG2 copes much better with noisy content... :rolleyes:


Bye

SammyRoss
10th April 2004, 19:52
In answer to 'b' - It all depends on the encoding application. MPEGmediator will also let you import Mpeg1 or 2 files that contain audio

So what's your personal preference encoding-application-wise?

Thanks everyone, for bearing with me.

SeeMoreDigital
10th April 2004, 20:10
Originally posted by SammyRoss
So what's your personal preference encoding-application-wise?

Thanks everyone, for bearing with me. Without doubt, it's the latest XviD (http://koepi.roeder.goe.net/xvid.shtml) build.

It's a very flexible codec and if used correctly, you'll be able to burn your files to CD or DVD and watch them on a TV via suitably equipped DVD/Mpeg4 stand-alone player!

Cheers

SammyRoss
10th April 2004, 22:56
Well, XviD is the codec. What I actually meant was, the actual encoding application that uses the codec. VirtualDub? Is there anything more user friendly? If not, where can I find a comprehensive guide?

SeeMoreDigital
10th April 2004, 23:17
Originally posted by SammyRoss
...What I actually meant was, the actual encoding application that uses the codec. VirtualDub? Is there anything more user friendly? If not, where can I find a comprehensive guide? Well, I find MPEGmediator to be very user friendly.

But like all encoding 'front ends' it does things in its own way. I like it because I prefer to encode using the same image pixel frame size as the source ie: 1:1. (for an NTSC DVD that would be 720x480 and for a PAL DVD it's 720x576).

Cheers

SammyRoss
10th April 2004, 23:27
Where can I find it? Can you post a file? mpegmediator.com seems to be down... or is it my ISP?

SeeMoreDigital
10th April 2004, 23:36
Originally posted by SammyRoss
Where can I find it? Can you post a file? mpegmediator.com seems to be down... or is it my ISP? Try here (http://82.2.167.24/Uploaded_Files/Doom9_Forum_files/MPEGmediator_(v1.5).zip).

Cheers