avi vs mp4

[KoenP2]

Hi,

I experience very big file size difference rendering to avi or mp4.

I always believed avi files would be smaller than mp4 my adobe premiere 10  gives other result. Am I doing something wrong here? And what are the pros and cons to avi or mp4?

Thanks for replying,

Koen

[Steve Grisetti]

Well, there is no one definition of an avi or an mp4, Koen.

An AVI is just a package, an envelope. What's inside it can be made up of any of thousands of codecs (compression systems), from DV to Divx and anything in between. So some AVIs are large and others are very small.

Likewise, MP4s are usually created using the H.264 codec -- but often are not. Sometimes product makers create their own codecs in order to, for instance, squeeze lots of video onto a very small memory card. In addition, MP4s can be created at a variety of quality levels. An MP4 you view online, for instance, can be very different (and a very different size) than one you view on your iPad.

In other words, comparing MP4s to AVIs is not only like comparing apples to oranges -- it's like comparing any of thousands of varieties of apples to any of hundreds of varieties of oranges.

[John T Smith]

Some reading...

Read Bill Hunt on a file type as WRAPPER http://forums.adobe.com/thread/440037?tstart=0

What is a CODEC... a Primer http://forums.adobe.com/thread/546811?tstart=0

What CODEC is INSIDE that file? http://forums.adobe.com/thread/440037?tstart=0

.

Report back with the codec details of your file, use the programs below

.

For PC http://www.headbands.com/gspot/ or http://mediainfo.sourceforge.net/en

For Mac http://mediainfo.massanti.com/

[KoenP2]

Hi,

Well that is a lot of information when I read the 3 answers on my, (in my mind simple) question.

I am using Adobe Premiere 10 and have editted a video to be shown on the web.

A 10 minute  movie MP4 format results in 521MB  now I than receive 'complaints' my moviefile is too big with an advice to render it not as MP4 but as AVI file.

That's why I queried for the differences in MP4 and AVI.

John, upon your advice I have now used MediaInfo the answers I get:

Format MPEG-PS

Codecs MPEG-2

and further more:

192 Kbps, 48.0 KHz, 16  bitsk 2 channels, AC-3(DVD-Video)

Question: is this 521MB acceptable or can I choose an other otion / parameter on Render(Share) my video resulting the file to be smaller without remarkable quality loss - mind I am not looking for A1 Qlty, medium reasonable will do.

In Adobe on tab Share I select:

MPEG   and under Advanced... I select Quality 3  

Your reply is appreciated.

Best regards,

Koen

[nealeh]

Initially I suggest you try the standard PRE10 upload *TO* Facebook or YouTube options. They should produce 'medium reasonable' quality. If they look good enough you can then download the file *FROM* Facebook or YouTube to display on your webpage.

Cheers,
--
Neale
Insanity is hereditary, you get it from your children

[Steve Grisetti]

And now you're finally getting to the bottom line, Koen!

Instead of thinking file formats -- think about how you want to use or display your file. As Neale says, there are optimal settings for creating a file to view online.

http://forums.adobe.com/thread/623549?tstart=0

If you start at the end, it's always easier to work back to the beginning.

[KoenP2]

Steve,

That sounds fine. Now I could do a trial and error, however a render takes about 1,5 hours, so I might endup somewhere after midnight , could you tell me as Adobe Premiere 10 is slightly more sofisticated as your thread 623549.

b Video Tab

*Video Codec: H.264

*Quality: 100

*Frame Wdith: 1280

*Frame Height: 720

*Frame Rate: 29.97   this, I suppose for PAL should be set to 25 ?

*Field Type: Progressive

*Pixel Aspect Ratio: square

*Set Bitrate: checked

*Bitrate: 8000 kbps   there is no Bitrate but a checkbox which allows you to Limit the rate to n kbps. Where when n = 1000 my 512kb file is estimated on 76 kb only, setting it to 8000 gives an estimated 612 kb

Now do I choose a low n or 8000 ?  What is the effect of a low n value, I presume lousy qlty?

Regards,

Koen

[the_wine_snob]

In addition to what Steve and John have offered, the two main determinants of AV file size are:

Duration

Bit-Rate

The CODEC used has a little effect, but mostly they allow for the data to be compressed, yet still leave acceptable quality. The lower the Bit-Rate, the lower the quality, but also the smaller the file.

Where CODEC's differ is by the allowable compression of the data, coupled with the acceptable quality. Some are better at the compression, than are others. The H.264 CODEC, usually found in MP4 wrappers, is very good at giving one acceptable quality, but still compressing with lower Bit-Rates.

Many of the CODEC's, commonly found in the AVI wrapper, are not quite so good, so to get the higher quality (read higher Bit-Rate), the files' sizes WILL be larger. One exception is the DivX CODEC, which does yield good quality, and lower Bit-Rates, and can compress the data very well. However, this CODEC is designed for delivery of streaming media, and is NOT meant to be edited later.

Editability is a big plus for the H.264 CODEC, and that is why it is used in so many HD formats, like AVCHD (a sub-set of H.264), today.

However, and with all of that said, there are major variations in H.264, so there are few universal specs. With DV-AVI, a particular CODEC, in the AVI wrapper, things are much simpler - the MicroSoft DV CODEC is standard, and uses low-compression, and higher Bit-Rates, to keep quality high, but at the sacrifice of file size.

There ARE a few CODEC's, usually wrapped as an AVI, like Lagarith Lossless and UT Lossless, that maintain lossless qualtiy, while still doing a good job at compression, but no where near as good, as most versions of H.264 - however, and just as their names imply, they are "visually" lossless - great quality, though at higher Bit-Rates and with larger file sizes, than most versions of H.264. For intermediate files, that will be edited later, I rely heavily on both of those lossless CODEC's. With the proper CODEC's installed, they both edit very, very well too. Also, one can do many generations of Encoding, without a noticeable loss in quality, where that is not true with H.264, where the compression will show an accumulation of a loss in quality, because of the high compression.

Hope that helps,

Hunt