[Len Reston]

Yeah this also a long post but mostly summarizes what I know about it from reading various forums and tinkering.

For now they seem to be using the &fmt=6 as their HQ, which is their so-called big flv 480×360 with 96Kbps mono audio – sometimes you see the HQ link for this format under the player, or is selected depending on client bandwidth/user settings. Their &fmt=12 is the old 320×240 flv, both h.263. These extensions are for YT’s testing and was discovered I think in early Feb 08 but don’t know for sure.

I’ve seen something called a greasemonkey script for firefox to either put the =18 link in the page or auto-append it. There are other methods out there – haven’t used them though. Despite all this there’s really no knowing what YT will settle with. IMO the =18 with stereo is the most pleasing even though audio goes thru a “compressor” and makes everything very loud. Background sounds are elevated.

It looks like all the settings should be OK. Wouldn’t use too few frames per keyframe. As an experiment I tried 1 frame/keyframe. It severly reduces compresson, caused the bit rate to climb to the limit set at 4Mbps and looked very poor, as in running out of bits. It was backed off to 15 per keyframe. 24 probably results in a lower average bit rate. I think you can reduce bit rate until you see lower quality. 4Mbps is arbitrary because with YT’s 1GB limit, you can upload a 10 minute vid with over 13Mbps total rate. Perhaps maxing out with 720p is good idea if you believe YT will survive well into several upgrades later when HD may be the norm on a global scale.

I forgot to mention that on this one

https://www.youtube.com/watch?v=BO5c_Ktpdf8&fmt=18

I used QT PRO because I realized the demos are QT files anyway (duh). It is 16Mbps 1920x1080i 29.97fps H.264, 44.1KHz 2ch PCM. It was uploaded as 15 frames per keyframe, single pass, frame reordering checked,no filters, h.264 480×360 restrict to 4Mbps, sound 320Kbps aac lc abr best. No deinterlace since can’t tell difference when source is 1080 high resized to 270.

From watching the Mustique11, I see it’s very sharp and full frame. There’s a lot of motion at times. From MediaInfo it’s at 29.97fps. (Was that your cam frame rate? YT uses source frame rate though can’t be sure in every case.) This puts a heavy load on the codec (more blocking). The Canon consumer demos are very conservative with motion as their cam codecs don’t handle motion very well. Their vids look good on YT’s h.264 with 16:9 letterbox even if left sharp. When there’s lots of motion I either soften (don’t have motion blur) slightly overall, and/or add black frames (or virtually “no activity frames” same properties, frame rate size etc) to the end of the video, like 2/3 to 1x the length of the vid or even more if it’s a short clip (too much and it may buffer in the player). This causes the codec to shift more bits to the active video portion – the avg bit rate is about the same. The no activity period is kinda annoying but it benefits all three YT versions if the vid itself isn’t too long. It benefits uploaded flv’s the most when you can adjust bit rate of the actual file that will be loaded into the player, IMO. You never know when YT might squash file padding, as they have with the hex edited flv.

There’s also the option of dropping the frame rate to 25, 24 or 20 resulting in some judder if different from your camera rate – it might be a better tradeoff than the erratic blocking of the codec. YT may be interested in encoding speed at the expense of some quality. Someone wondered what could be google’s power bill as they encode all the videos on their servers to the new versions. And some have observed repeated re-encoding of their videos – even as far back as early 06.

[Len Reston]

To see YT’s h.264 aac version they are testing, append &fmt=18 to the URL.

canon hv20 demo example:
https://www.youtube.com/watch?v=WcaYgZoVIOE&fmt=18

I’m using vegas platinum and x264vfw codec, intel version of h.264. My basic settings (by no means optimal) for uploading to YT are: 480×360 (same as their player) square pixels, x264 codec is set to “single pass – bitrate-based (ABR)” 4Mbps, other codec settings as default. platinum render settings: frame rate same as source, deinterlace, audio interleave every 250ms, either 320Kbps mp3 joint stereo (FhG from wmp11) or 44.1K 2ch PCM.

[Len Reston]

Append YT URL with &fmt=18 for their h.264 aac version. They started stereo aac Mar 8-9th and once again appear to be re-encoding all files on their server. I’ve been uploading 480×360 x264 4Mbps, 44.1KHz 2ch PCM. Only problem is YT’s audio “compressor” that makes everything sound loud. They may have their reasons or it is seriously mal-adjusted.