@jak.willis

Hi Jak.

Because there is no compression. Each pixel will be recorded individually even if it's neighboring pixels has exactly the same 'setting'. Nothing is grouped or shared, so a frame that could have 'shared' 90% of its information with another frame will not share that information and be recorded again. That results in a huge amount of extra data being produced.

Ray.

Ah, I see. So it’s not like it’s un-compressing the source video and reverting it back to it’s raw form, how it was before it was compressed in-camera?

@jak.willis

Correct. There is neither no gain or loss. Any 'lossy' compression codec means exactly that. Some information is irrecoverably lost. Even if you have a camera that records raw, if the camera is set up wrong and either over exposes or under exposes, highlight or shadow detail is still lost. Same as in a digital still raw file.

@jak.willis

Correct. There is neither no gain or loss. Any 'lossy' compression codec means exactly that. Some information is irrecoverably lost. Even if you have a camera that records raw, if the camera is set up wrong and either over exposes or under exposes, highlight or shadow detail is still lost. Same as in a digital still raw file.

Yeah, I see. So, in simple terms, if you decide to export your project as an uncompressed AVI file, then why is it that the data rate ends up being huge? Sorry to keep going on about this but, as you can probably tell, I am very keen to learn and understand these things.

Also, out of curiosity, I took a random 720x576 MPG file from my PC hard drive, imported it into MEP, exported a small chunk of the video as uncompressed AVI, then put the file on to a USB Flash Drive so that I could then attempt to play it on my TV & Blu-ray Player to see what happens. And what happened was it came up with "Resolution not supported" with only the audio playing - but that was stuttering. Any ideas as to why this happened?

@jak.willis

Basically the data rate is too huge for the TVs processor to keep up with, even if it could read an AVI encoded file.

Or the usb flash drive is not fast enough which could be another reason. Last but not least, a lot of digital TVs only support a few codecs. Normally listed in their manuals.

Normal use of such an AVI file would be purely archival in nature. A base file that can be re-edited at a later stage if need be. Typically for me it would be a waist of time producing them if I had the original files.

@jak.willis @CubeAce

I wouldn't be so sure about the data rate being too high. Uncompressed video does not need decoding. That is why editing it in say MEP is so easy. The program does not have to do any work to decode it, unlike an MP4, where MEP will have a much harder time decoding.

I agree with Cubace on the USB drive; it's data throughput speed is probably not enough. Put it on a portable SSD and you will have a better result. However, as CA says, I very much doubt any TV or Pluray player would even play it, as the codec wouldn't be supported.

AVI certainly has a role. For example, the best way to capture VHS (or nay analogue source) is to capture as an AVI. I will caveat this by saying we never capture "uncompressed", we capture "lossless" using a lossless codec such as Lagarith, HUFFYUV or MagicYUV. These codecs result in much smaller files (around 450mb per minute as opposed to 1gb per minute for uncompressed). Working with these lossless AVIs means you can do multiple saves and effectively, no quality is lost. I recently had a awful piece of video that I had to run through multiple programs to get it looking good, all in AVI format. You could never do that with MPEG 2 or 4 without losing quality along the way.

So, in simple terms, if you decide to export your project as an uncompressed AVI file, then why is it that the data rate ends up being huge? 

Cubeace gave you the answer above:

Because there is no compression. Each pixel will be recorded individually even if it's neighboring pixels has exactly the same 'setting'. Nothing is grouped or shared, so a frame that could have 'shared' 90% of its information with another frame will not share that information and be recorded again. That results in a huge amount of extra data being produced.

@jak.willis @CubeAce

as the codec wouldn't be supported.

What codec? If it's uncompressed then it doesn't use a codec, does it?

That's why I was asking because I used to assume that if you chose to export a project as uncompressed AVI, that the original bit rate of the video file would be retained because there's no compression. A bit like how Smart Render works. So I got confused wondering why it was that the bit rate of the uncompressed file would be much larger than the source file sitting on the timeline.

@AAProds

Good ol' Anna Logg.

I knew I had forgotten a good reason to have avi. In that instance it does make a lot of sense to use before the final edit.

Ray.

@jak.willis

What codec? If it's uncompressed then it doesn't use a codec, does it?

Yes, technically you're right. My point was TVs and BD players are (I assume) not designed to play uncompressed video.

@CubeAce Anna Logg. I like it!

@jak.willis

Any 'codec' is an instruction set that tells the computer how to construct the data into a file that can be read by another program. In this case to show a video. Compression or not does not come into the equation. It is still an encoding of another file or in AAProds case the digitized signal he gets from the convertor he uses to capture the analog signal from his VHS tapes.

[Edit] The file will still need to contain frame rate information, picture size, audio sampling rates, type of audio codec used, etc.

Ray.