The path to video conversion is laden with wasted time — mine specifically, so I'm sharing my experiences in hopes it'll save you some cycles. By "video conversion", I mean both "download YouTube videos"-type encoding utilities on the web and standard desktop applications. It's very easy to find something that'll do a mediocre or "OK" job, but quite a quandary to really get self-assured excellence with minimal effort out of the choices available.

I'll start with the best I've found, then move on to the shameful cowcrap. iDesktop.tv (formerly YouTube Desktop) is a more rewarding and less-ugly way to traverse the straits of video-hosting-giant-and-Google-property YouTube. It's a primarily visual browser, using thumbnails and icons to communicate what you can do. As I blogged earlier, I found iDesktop.tv to generally be rewarding in its earlier incarnation, and I disclaim they've quoted my words.

But really, and here's where I expound my controlled rage: why are there so many broken, awful, cloney video encoders which add nothing to the already-existing, confusing world of software? Usability-wise, they're near-bankrupt. I used to like Vixy.net for its straightforward approach (remember?), and some variants have sprung up — some suspiciously aping the same tech — but I'm downright disappointed at how often they (as a general collective) return "server too busy" messages. It's unpleasant and leaves less-tenacious souls at a dead end.
 

Compounding the disappointment, Vixy.net released a desktop app beta, which I was excited to see, but here's where things go sour: besides its understandable debut as adware, after you successfully encode a video (thank goodness it appears to work reliably, unlike its web counterpart — which used to be a lot better), all the settings are locked out so you're forced to quit and reopen it to encode the next video. What an awful interface!

Even worse, aside from reliability, Vixy desktop offers nothing really advantageous over the web version: it chugs along relatively slowly (it is kinda nice that it doesn't noticeably consume your local CPU power, but then again, things might run faster on a good rig, 'specially if it was multithreading-optimized), there's no batch encoding, and glaringly suffers from #5 (see below). So throw that in the pile you don't need to trouble yourself with, and let's continue.

Sure, I've found misc. lists of "How to download videos from YouTube or [insert video-sharing site here]" like Mashable's (thanx guys, you have a lot of neatly-compiled articles I've found useful!), but by far and large, the majority of those tools — and I've tried over 20+ of them, one disappointment after another — suffer from one or more significant flaws, and thus, aren't worth trying. Why bother with surplus complexity of choice when one decent utility will suffice?

I classify these flaws into the following 7 buckets:
 

1. Poor encoding quality - YouTube and other web video is generally in Flash (.FLV) format, which is heavily-compressed, likely very blurry and pixelated, and remember that video is already compressed before it ever gets uploaded to one of these services, compounding the artifacting damage. A lot of these encoders mangle the "quality" nth degrees worse, making the end result painfully fuzzy and a warbled horror to listen to.
     
    
2. Wasteful encoding settings - One plus to a lot of these Flash vids is they're small on filesize. Yet, these encoders will bloat the size a magnitude of times when converting to a more comment format. I'm shocked at how many encoders will use hoggier settings for already-crushed video, e.g., 44.100 khz stereo audio where YouTube has already smushed it down to 22.050 khz mono (that's right, those many music videos are in monaural sound). All of this slop adds up to bigger files and higher bitrates you don't need, because THERE'S NO ADDITIONAL QUALITY TO BE GAINED!
     
    
3. Too slow - Time is short, but a surprising number of desktop encoders don't use optimized algorithms, and in some cases, take a lot longer to encode for an imperceptible gain in quality compared to other methods. To add insult to injury, most of the desktop encoders I tried weren't multithreaded to make use of multiple CPU cores — not very tolerable in an era where dual-core computers are increasingly cheap & common. Even worse, they don't allow you to start multiple instances, leaving fractions of your total CPU usage idle which you'd be better off putting to use. And as for the web ones, frequent "server too busy" errors and other timeouts are rampant.
     
    
4. Too confusing to use - This is especially true of the more powerful tools, like FFmpeg (which, to its credit, does boast a very nice Mac version, ffmpegX). Obviously, video encoding is an advanced art & science; I have no end of respect for the engineers who've contributed to efforts to advance the balance of better quality at smaller filesizes.
    
   Regardless, making powerful technology available to the masses is fundamental to widespread adoption and lessened headaches — remember what iTunes did for streamlining the audio encoding workflow, its reach multiplied exponentially in recent years by the iPod? And what good are powerful tools if you don't know how to use them? As a prime counterexample, I've heard SUPER © touted, but I didn't get a lot of joy out of it because its button-stuffed UI is shockingly mediocre.
    
   
    
   Furthermore, the download link on the website is tragically easy-to-miss…
    
    

   … contrast that aberrant, TL;DR-y sadness with the easy presets in Apple's QuickTime Player (and yes, more devs big and small should follow Apple's usability lead), which don't obscure the more advanced settings, but allow those who don't care to get started easily. And that's what counts.
     
    

5. Outputs cryptic filenames - One of several areas where iDesktop.tv notably excelled in where so many others fell short of the mark! After done encoding, a lot of these "tools" will popup a dialog that looks like this:
    
   
    
   WHAT IN THE HOLY WATERMELON'S NAME!??? Why squander my time renaming the file when the original likely had a clear and understandable title on the webpage it was on? What dickish tomfoolery! In sharp contrast, iDesktop.tv conveniently just grabs that title, with the exception of when special characters like "|" are used, in which case stuff gets unpleasantly gets truncated. Better still would be to exclude those characters. Nevertheless, I'm surprised this is so hard to get right — even Vixy lifts the YouTube code instead of the human-readable text.
    
   The desktop encoders are somewhat better, often simply drawing on the original filename, but… that's not a lot to root for. And as another black mark against them, their methods for selecting an output directory, something that should be drop-dead easy, are often arcane and obscured.
     
    
6. Disappointing presets - Good presets make a big difference in terms of being able to grasp a new tool effectively, softening the learning curve and leading to results you're pleased with. From synthesizers to my work on WindLight, I've experienced how true this is many, many times over. When video encoders offer presets, they often look like a haphazard jumble of numbers without a how or why you should pick X over Y.
    
   
    
   QuickTime's own Player is among the better ones in this regard, but it doesn't offer integrated batch encoding (I've read of ways to extend it with AppleScript or other methods too hassle-full for the casual user).
     
    
7. Lack of product differentiation - I've got a righteous gripe here, because Googling for "youtube video converter" and similar phrases turns up so a minefield of results. Many of the matches for offered programs are generic, inelegant, and do nothing to serve you, the user, insofar as how they'll encode videos well. (I suspect many are different but commonly-lousy frontends grafted atop the same backends and/or libraries.) This only reinforces my case for a few standouts to shine in a sea of suck.
    

And in said sea of suck, how do you choose?

One of the few that really stood out to me for its clean layout was the (ironically) generically-named Media Converter (another victim of #5). I really had high hopes after browsing the website and finding out about its desktop client. Unfortunately for the latter, changing its settings appeared to not actually do anything — the one test video I encoded into various bitrates resulted in files that were ALL THE SAME SIZE — leaving me frustrated and reaching for the uninstaller. A typical reaction to what I endured; I reckon most folks won't even be as patient to stick around and try fiddling with little settings. To be fair, Media Converter's web conversion service seems to be more robust than "the rest of the crowd".

*moves onto the next*

Zamzar does conversions in multiple formats. In addition to video, it also handles many standard extensions like DOC, XLS, PPT, etc. With an awkward downside of needing to email you the link to the converted file if you're a free user, it works decently, but is also prone to #5, and oddly lets you browse for multiple local files to convert, but only one remote URL at a time. Someone's gotta do a sparkling web video converter that does batch converting of already-online stuff more gracefully — even iDesktop.tv has troubles with this (read on).

*breath*

Beyond this, an eclectic-and-related note I passionately need to put out: Sony Vegas Video doesn't render "correct" H.264 videos. I'm generally a fan of this non-linear editor and have used it to prepare every single one of my video tutorials, piano performances, and more; apparently, they didn't or couldn't license Apple's AAC as part of the codec package, so it's frustrating being limited to use MainConcept or Sony's inferior AVC/AAC, and here's why: encode a Vegas project in either of those, and open it in QuickTime Player. Then, go to Window menu > Show Movie Properties and you'll notice video data is listed as "-NA-". Argh!

Even more frustrating, the first frame of the video will be black — you won't see any content until you scrub through the footage — and worst of all, trying to export the vid into another format spews this lame error:

I've also verified that some more commercial encoders like Sorenson Squeeze 4.5 don't handle Vegas' quasi-MP4 either, and after an exhaustive round of websearches, and I haven't found anyone else who's noted this, so maybe it's the first. In any case, I hope it helps lost travelers wondering why.

Sony, this ain't an open letter, but if you can, please support all codecs that Apple's QuickTime does so your users can benefit from some widely-used and wonderfully efficient formats, as anyone who's enjoyed Apple Trailers is aware. And if you can't do this for whatever technical/legal/etc. reason, please communicate why. And for that matter, I wonder if competitors like Adobe Premiere support rendering in all QuickTime codecs… does anyone know?

An aside: as noted, a bulk of the above applies to the web, so it isn't strictly platform-specific. However, my main rig is a Windows PC, and the desktop apps I've tried are mainly for Windows. Besides QuickTime originating and continuing to pave the way on the Mac, Macs appear to have a lucrative advantage in video encoding with notables like ffmpegX and HandBrake (compared to the Windows version) being superior version to their Windows analogues. I haven't had great experience with these, but they look a lot more compelling. Even some higher-end commercial apps like Autodesk Cleaner and Final Cut Compressor are Mac-only. (Makes me almost wanna go OSx86.)

Now that I've shown you why there's so much suckage in terms of an easy path to video encoding, I believe the market has a lot of ripe opportunities for some fresh upstarts to come in and do something great. Perhaps not insanely so, but nevertheless, there are gaping holes just waiting to be filled.

Today, I suggest investigating Media Converter and Zamzar if you're looking for more general-purpose and FREE video conversion tools on the web,

and if you specifically spend a lot of time on YouTube and want to download YT vids to your computer, I give iDesktop.tv my recommendation, with some caveats you should know about, including:

• It allows you to queue vids for download without fuss in an OS X Dock-ish tray, but right-clicking on the thumbnails to select a format, or clicking on the little format icons if you'd rather do that, is difficult and fiddly.
   
• Downloading more than one vid at a time doesn't work reliably: it'll often leave a little circular spinner (meant to indicate indefinite progress) stuck, and I find myself having to refresh the page and re-download. Like downloading a video to convert (which is a queue-able, pretty reliable process), the actual convert-and-download should include a progress bar and be queue-able.
   
• Export to MOV, not MP4 if you want better audio quality. I don't know if this is an inherent technical deficiency, but iDesktop's MOV and MP4 appear to have identical video, but different audio, with the former being MP3 and the latter being AAC, both @ 22.050 khz. Unfortunately, the AAC has the high-end lopped off, meaning the treble range is muffled and weak. Filesizes are comparable, so I haven't seen any advantageous reason to go for MP4 over MOV here. Compare them for yourself and see, er, hear what you think.
   
• The QuickTime-compatible vids it converts aren't web-streamable. This should be the default, as makes for a slightly-larger filesize for such an advantageous feature. (I vaguely recall Vixy.net's converted .MOVs were web-streamable, but the desktop version's currently aren't.)
   
  This means after saving a video to disk, if you want it to play on-the-fly, you need to:
   
  
   
  1. Open it up in QuickTime Player.
  2. File menu > Export.
  3. In the "Save exported file as" dialog next to "Export", select "Movie to Hinted Movie". "Use" = "Default Settings". (I think the recent File menu > Export for Web will also work for more elaborate purposes.)
  4. Save.

All those steps add up to more wasted time when repeated across many videos — it's obvious I love automation wherever I can use it! After all, I slogged through all of the above because I was looking for a better way to make my Second Life Tip of the Week video tutorials available for download.

I hope the iDesktop.tv crew (whose contact info is hard to find) will fix these errata, and keep improving their service. Sign up for a free account, import your faves + playlists from your existing YouTube account, and see how you like it. And let me know in the comments about what I've missed out and what tools you prefer to convert videos!