AVI Question

[alanball]

Hi all
I have been downloading video files from my old tape camera which are AVI format using the old DVIO.EXE which never seems to fail, as I'm sure Lata will confirm as he told me about it 10 or more years ago!!

My question is, is MPEG2 still the best format to save the AVI files as? I dont know much about the ins and outs of AVI but there must be lots of detailed information in them being so large files.
Thanks

[Ken Berry]

I guess it all depends on what you intend to do with the video. Is it AVI or DV/AVI? If AVI, then that will (or should) play on your (HD)TV. MPEG-2 will also play directly on your TV, and of course be made into a DVD. But you could also convert it to mpeg-4, which has become a more popular format for sending and playing on the TV.

[alanball]

Thanks for reply Ken, would the mpeg-4 be the same resolution as the Mpeg-2?

[alanball]

Sorry Ken its dv/avi

[Ken Berry]

The quality should be the same depending on the mpeg-4 bitrate you choose but the size of the new video clip will be smaller than an mpeg-2. It's good that it is DV/AVI as that at least preserves the quality of the original video -- even though it will still probably be less than standard def digital video.

[Davidk]

Theoretically, AVI was the original video format, owned by Microsoft. Everyone was horrified at the sizes of files it produced.
Time passed, and a standards committee devised mpeg-2 (MPG), which is the standard definition commonly referred to now, and achieved the same result (with a small definition loss) as AVI, but with compression in a file format that is half the size of AVI for an equivalent recording.

Some people still horrified at file size, especially with the progression to high definition imagery, so standards committee devised MP4 which had different compression algorithm and achieved a file size of half MPG or 1/4 avi for an equivalent recording. But now, mp4 is a carrier format - can have several varieties of resolution within that structure, so in addition to achieving a much reduced file size you now have to pay attention to frame resolution of the imagery.

With increasing screen resolution requirements, using a file structure that doesn't take the entire disk is an operational necessity. Beyond HD, there is 4K and 8k is getting a run is the latest screens available. And resolution seriously impacts on the capacity of computers to display video in those formats using HD and 4k: the amount of data needed to be process for every frame increases exponentially with higher resolution requirements: a frame rate of 25 (30 for NTSC) fps is still a display need, but the information to be processed for each frame is going up dramatically. See attached image for comparisons. And thus the need for proxy files in VS.

[asik1]

I saved all my DV stuff as 3mb WMV's
90min takes about 2 gig.

[Ken Berry]

But will WIMVs play natively on a TV?

[asik1]

But will WIMVs play natively on a TV?

all the ones that matters of those files have streamers .

[canuck]

But will WIMVs play natively on a TV?

all the ones that matters of those files have streamers .

What does that mean?

[lata]

DV.Avi was used by Mini DV camcorders- Hi8 etc. a lossless format, earlier camcorders were analogue
When we transfer DV.Avi to the pc, and I say transfer that is what we do, no recoding so what we got was the same as recorded on tape DV.Avi. Quality was excellent at 13 Gb per hour should be good even for standard definition.
Analogue camcorders used a process to capture the video, this involved transcoding on the fly, converting the analogue stream to digital to produce a Mpeg2 file, (4Gb per hour ish) at least that was the norm. getting the settings correct was essential to creating good quality.

Interlaced re Progressive
DV-Avi format were interlaced using Lower Field First.
Earlier video studio programs also defaulted to use LFF, so doing Share – Mpeg2 would use LFF to match
This changed with the introduction of Digital HD formats, Video Studio now uses UFF by default.
If we are to convert DV-AVI using Video Studio we would need to create our own template to use LFF
The other option would be to use Frame Based (Progressive) rather than interlacing.
Fortunately, all Mpeg4 templates appear to use progressive

Frame Size
Dv-Avi is a standard definition format using 720 x 576 (Pal) and I assume using 16:9 ratio older video may have been 4:3
You should try rendering to Mpeg4 1920 x 1080 25P
Does that play on your TV and at what quality?

As a test you should try other formats to compare quality, and to find the ones that play on your TV.
Render times could also a factor in your decision.

[alanball]

Thanks guy’s for all the useful comments and the background history lessons From DavidK and Lata.

Looks as though I’ve got some trials to do.
Thanks again for all your help.