MPEG-4 ~ what's the difference?

[kr236rk]

Hi,

What's the difference, please, between the many softwares offering to convert/compress video's into MPEG4 format?

for example, Roxio offer a "Buzz" download programme for converting videos

http://www.roxio.com/enu/solutions/roxiolabs/products/buzz/default.html

whereas Sorenson Media retail a disc doing basically the same thing, in terms of MPEG4 creation

http://www.sorensonmedia.com/pages/?pageID=2

and i was wondering what the difference might be between the resulting MPEG4 files

1) file size?

2) image quality?

3) compression rate?

another example is that i run Pinnacle 9 dv edit software, and its MPEG4 file properties read something like "old MPEG" - does this mean that there are different MPEG4's around: all called '4', but still not the same as each other?

thanks

Ric

[Baldrick]

I guess that all those means mpeg4 sp/asp = divx or xvid for example. Mpeg4 can also be h264 but it will usually mention either h264 or avc then.

1,2,3) It depends on the video bitrate. You will get similiar results with most mpeg4 sp/asp variants and a bit better video quality with mpeg4 h264.

Read http://en.wikipedia.org/wiki/Mpeg4

[kr236rk]

I guess that all those means mpeg4 sp/asp = divx or xvid for example. Mpeg4 can also be h264 but it will usually mention either h264 or avc then.

(quality) ... depends on the video bitrate. You will get similiar results with most mpeg4 sp/asp variants and a bit better video quality with mpeg4 h264.

Read http://en.wikipedia.org/wiki/Mpeg4

many thanks

which is the best MPEG *compressed file size : image quality* MPEG4 type, please - h264?

and, if this is also determined by the source video, which is the best dv type for optimal compression to high quality MPEG4?

bests

R

[jagabo]

h.264 gives the most compression under most circumstances. But it takes much longer to encode than Divx/Xvid and much more horsepower to play back. Many DVD players will play Divx/Xvid in an AVI container. Few will play h.264.

[gilamran2]

is there a place with many video files, each with a different format.
so we can see the difference? like size/file size/bit rate/ covertion time. etc

???

[jagabo]

Doom9 used to do codec comparisons:

http://www.doom9.org/codecs-final-105-1.htm
http://www.doom9.org/codecs-104-1.htm
http://www.doom9.org/codecs-103-1.htm

I would take them with a grain of salt given the limited number of video files tested and the limited number of settings.

Extremetech did some tests in 2004:

http://www.extremetech.com/article2/0,1558,1544886,00.asp

As a very general rule you'll find that MPEG4 ASP (Divx/Xvid) can get about the same quality as DVD MPEG2 at about half the bitrate. MPEG4 AVC (h.264) will give about the same quality as DVD at 1/4 to 1/3 the bitrate. This is with the same frame size and frame rate. Keep in mind that most MPEG4 files you'll find on the internet have the frame size reduced to 640x368 or less so they can get away with lower bitrates.

[kr236rk]

this is very helpful, fascinating, helpful, and thanks - but i am still confused

theoretical example

folks upload compressed videos to the web, some are questionable quality and lacking in definition, whilst others are well defined and look seamlessly smooth: presumably, the majority of these uploads are MPEG-4 [don't think any dv web sites give you file / codec info, on what's already up there (even your own)], but what is the main factor determining a high or low quality result, and what can the guy behind the video do, to choose the optimal software for the job - is there also a commercial software guide on the web, or on Doom, for example, re MPEG-4 quality - with regard to commercially available editors / AVI compressors?

many thanks again

R

[TBoneit]

"some are questionable quality and lacking in definition" simply because they are overcompressed and bit starved to keep file size down.

There is no way a 700Megabyte file can hold a 2 hour movie and look good.

As jagabo states many inexpensive DVD / Divx player will play a Divx or Xvid as long as it was done in such a way as to squeeze every last bit of file size.

The Philips 5990 now plays WMVs as well as AVIs and MPGs.

If it is a DVD movie then as cheap as DVD blanks are just leave it as a DVD movie and retain the quality.

[kr236rk]

thanks

is it better to shop around and download individual compressors, or go for the MPEG-4 converters found in package software, like Pinnacle, Roxio or Movavi, please?

or is the difference negligable - in terms of bit rate, and so forth?

i suppose the ideal situation is to have a compression software which allows you to vary bit rate, file size and all other potential variables; as far as i am aware, commercial dv editors offer predefined files, which cannot be customised?

thanks again for helping up this learning curve!



Ric

[jagabo]

folks upload compressed videos to the web, some are questionable quality and lacking in definition, whilst others are well defined and look seamlessly smooth: presumably, the majority of these uploads are MPEG-4 [don't think any dv web sites give you file / codec info, on what's already up there (even your own)], but what is the main factor determining a high or low quality result, and what can the guy behind the video do, to choose the optimal software for the job - is there also a commercial software guide on the web, or on Doom, for example, re MPEG-4 quality - with regard to commercially available editors / AVI compressors?

With all the high compression codecs you pick the file size you want, usually indirectly by selecting the bitrate (file size = bitrate * running time). The bad quality videos you see are from using too low a bitrate for the video. This is usually done simply to meet a size requirement (to fit a 2 hour movie on a CD, for example). If you have to have a specific size you can use a smaller frame size to get higher quality but you will be trading off spacial resolution to get fewer macroblocks. You can also use a lower frame rate, in which case you are trading off temporal resolution to get fewer macroblocks.

Many of the codecs have constant quality modes where you select the quality you want and the encoder uses whatever bitrate is needed at each frame to deliver that quality. You don't know exactly how big a file you will get until the conversion is done. I always use this type of encoding when making Xvid AVI files.

The program used to create the compressed files can make a difference in the final quality when processing is needed before compression. For example, deinterlacing methods differ from program to program.

All in one packages like Pinnacle's, Roxio's, etc. usually do not to the best job.

Going from DV to DV you have no choices. DV is a fixed frame size, fixed frame rate, and fixed bitrate. Most programs that convert from DV to MPEG or Divx may have fixed templates but they usually let you make adjustments.

[kr236rk]

thanks Jagabo,

can you suggest a software ~ commercial or custom-download ~ which gives the user control - so that a degree of experimentation is possible - over bit rate, encoding, and so forth - i am particulaly thinking of projects streaming AVI into MPEG-4, since burning/creating dvd's is cool with me

R

[jagabo]

AviDemux and VirtualDub are free, have lots of filtering options, give you lots of control over the compression, and aren't too hard to use. VirtualDub only produces AVI files but AviDemux can create AVI, MPG, MP4, OGM, MKV, etc.

If you really want very detailed control over the filtering you'll need to learn AviSynth. Then you can use either of the above programs for the compression.

[kr236rk]

AviDemux and VirtualDub are free, have lots of filtering options, give you lots of control over the compression, and aren't too hard to use. VirtualDub only produces AVI files but AviDemux can create AVI, MPG, MP4, OGM, MKV, etc.

If you really want very detailed control over the filtering you'll need to learn AviSynth. Then you can use either of the above programs for the compression.

ah! - thanks - a light comes on

i used VirtualDub for my early film transfers to dv, so i have an amateur working knowledge of this software; somehow DivX video player came into this, as well; got as far as downloading AviSynth, but never used it: are there tutorials on the web for AviSynth, please?

AviDemux sounds cool 8)

bests

Ric

[jagabo]

If you have an old version of VirtualDub you should update to the latest beta. It supports source plugins that let it open MPG, MOV, MP4 and other files. Many source plugins can be found here:

http://forums.virtualdub.org/index.php?act=ST&f=7&t=12664&s=45c27a76cb3b999a09a214a28142a4a9

If you install the Divx or Xvid codec you can create AVI files with those codecs. You'll probably wan't LAME ACM for the audio. After installing the codecs you should be able to play the files with any media player.

For AviSynth tutorlials I'd start with the guides at this web site:

https://www.videohelp.com/guides?searchtext=&tools=77&madeby=&formatconversionselect=&h...or+List+Guides

And at AviSynth.org:

http://avisynth.org/mediawiki/Main_Page#New_to_AviSynth_-_start_here

You'll probably want AvsP and/or AvsEdit too.

[kr236rk]

thanks Jagabo,

very helpful -

this sounds like fun

bests

Ric

[ConverterCrazy]

I find this thread extremely useful and educative.

It should be part of Tutorials (Theory) for newbies and people like me who have limitations.

Needless to say, thank you all respondents to this thread.