Any downsides to WMV?

[sphinx99]

I'm trying to pick a codec to archive lots and lots of footage (type 1/2 DV, some high bit rate MPEG2, tons of lagarith/huffyuv stuff) in a fairly high quality but space conscious manner. I don't mind playback being limited to the Windows platform so long as I can transcode it out of WMV and into something else if I really *have* to play it elsewhere.

So platform limitations aside, are there any downsides or weaknesses to WMV in terms of editing, compression quality, encoder quality? I'm really liking WME which seems to work great and is easy to use; the compression quality seems to be at least comparable to the other current-gen codecs, and it seems that it's possible to transcode from WMV to something else if necessary. What are the downsides? I am not committed to any particular codec so I'm looking for any possible risks with WMV that I should consider before moving everything over. Thanks!

Appreciate any input!

[anonjon]

How does this compare with the latest DivX? Wouldn't that be superior? I'm a bigtime fan of DivX, but I'm not sure how well it compares with others.

[guns1inger]

All mpeg based encoders use temporal compression routines which make editing difficult. There are some mpeg2 editors that can use smart encoding to reduce the amount of re-encoding that is required, however I have not seen anything that does this for mpeg-4 based codecs (Divx/Xvid/WMV etc).

If you want to archive footage for the long haul so that it is editable in the future without quality loss due to re-encoding (and that is what you are going to have to do) then use a suitable codec. DV or a lossless codec would be the best choice. Yes, they are horribly inefficient for storage compared to mpeg based codecs, but they are designed for quality and editability. Mpeg based codecs are designed for compressibility and end-user playback.

Your problem is that you have conflicting requirements. If you want to store this footage in the best possible condition to work with in the future, put it all on DV tape, or buy lots of HDD space.

If you want efficient storage, accept that any highly compressed format will open you up to substantial quality degradation down the track.

[edDV]

"Editing" becomes problematic in all highly compressed MPeg4 formats including wmv but there are methods to get cuts to frame accuracy through estimation.

Standard rule is get your filtering and "editing" done as much as possible before compression.

DV, PAL, NTSC and 1080i are interlace and this presents problems converting to progressive. Inverse telecine when successful restores a true progressive film sequence. Other forms of deinterlace are highly destructive. The better techniques require memory and hardware filtering to get processing times reasonable.

VC-1 is the main focus for high quality interlace compression. The TV industry needs and demands a high quality interlace solution for transmission and archive. Interlace VC-1 isn't fully there yet but may be the best near future solution for DV and Digital Betacam format archiving. 1080i as well.
http://www.microsoft.com/windows/windowsmedia/howto/articles/vc1techoverview.aspx
http://en.wikipedia.org/wiki/VC-1
http://www.inlethd.com/support/vc10fourcc.html

First targets for VC-1 standardization include broadcast studio transmission and archiving at 1/3 to 1/2 current bitrates (e.g. 90 Mb/s Digital Betacam reduced to 40.5 Mb/s VC-1 MP@ML).

There are plans for Mpeg4 H.264 to better support interlace but at lower priority it seems compared to VC-1. These two formats have the widest industry support and are both part of the HD DVD and BluRay specifications.

[thecoalman]

so long as I can transcode it out of WMV and into something else if I really *have* to play it elsewhere.

Which is the Achilles heal of any highly compressed format, a single encode from DV-AVI to a high bitrate MPG introduces significant degradation. Not very visible but it's there when you zoom..... DV on the left 8000kbps MPEG on the right:



The question you have to ask yourself.... self :P ..... Are these important memories I'm trying to archive or just movies and othe junk that I've collected. If it's important get a external drive and store them there.

[sphinx99]

I'm taking a look at stills of footage encoded to WMV Advanced Profile with the codec bundled with WMP11, and with the various registry tweaks turned on (encoding takes forever!) and the quality is almost indistinguishable from the original at high bitrates (say 10-15mbit for 720x480 NTSC). By indistinguishable, I mean that if I take a still and diff them, there is very little degradation. Even luma and chroma noise seem to [mostly] survive the encoding process. I've gotten somewhat familiar with VC1 footage from HD-DVD on the PC (was one of the first with Toshiba's HD-DVD laptop) and have noticed the same there too: if VC1 can encode film grain, then it's good enough for me, since it's also 1/2 the size of 25mbit DV.

It also supports interlaced content which is nice!

Appreciate everyone's feedback so far. But regarding the posted example, I just don't think MPEG2 (even at high bit rates) is at all representative of VC1 at even higher bitrates for the same content. I'm not seeing blocking or other decode artifacts being that bad?

[Jiggytrav]

I've started to store everything in WMV format simply because it allows me to stream to my Xbox 360 (and thus my HDTV) via the Media Center or Tversity. In fact, the PC --> 360 has become my central hub for media in general and there limitless storage by adding HDD space and streaming. I'm also using WME and it seems to do a great job and there are plenty of options available.

On the other hand, if this is personal footage that you have captured, it would probably be better to keep it in the highest quality format that you captured it in (whether that's DV, etc). And I'm not doing much editing so WMV format is fine by me.

[thecoalman]

The point I'm trying to make is if it's important I'd suggest leaving it as-is. Any conversion introduces some degradation... The original will always be the best copy for the future... you don't know what's going to be avaialble 20 years from now and being able to fall back on the original copy will be important however minute the difference may be. I've always analogized it by asking if you would trhow away the negatives from your pictures? Of course if it's not precious family footage you are trying to archive it's not really that much of a concern.