Tuesday, June 2, 2009

Is the HQ35 Mystery Solved?

[This post is under review: Expect revisions soon (or not). Specifically, I spotted some issues in my test video that have me questioning some assumptions I've made so far. More detail will be added, once I've sorted out just how significant the effect of these discoveries may be on the issue at hand, getting smooth, high frame rate playback under HQ35 encoding and the related issue of getting the HQ35 encoding at all.

At this point, getting HQ35 has become such a rarity that I've backed off on seeking an answer to a question that has almost become moot.]

Sadly it's going to be a little hard to tell since so far, uploading test videos comparable to the ones in the previous demo of this problem will not seem to render to HQ35. However, without the alternating squares in each pair of frames, there still seems to have been significant progress, in this video.

and in this one:

The first video was rendered in Sony Vegas Pro 8.0c. Full specs are provided in the description section of the video's YouTube page.

I need to confirm just how the second video was rendered. I suspect it was done in Final Cut Pro, probably as a Quicktime container using H.264 video and AAC audio.

The key either way is to boost the number of reference frames or (in Quicktime) keyframes. Onno (maker of the animation) says that he increased the keyframes to 1 keyframe per frame... in other words, each frame is also a keyframe. I hope he will see fit to share more detailed rendering specs and settings that I can download and implement. This was discussed in some detail in a recent thread in YouTube's recently renovated Help Center.

A render of my adapted test video, with the alternating blocks appears below the fold.

Be warned, though, that at least at the time this was uploaded, it only received the HQ18 encoding. I suspect this may be because, to defeat frame droppage in HQ35, videos have to meet a certain standard of "compressibility," so as to avoid presenting them at such a high bit rate that they become too difficult, time consuming, (and costly) to stream effectively, particularly for those of us with slower connections.

So here's the one with the bouncing boxes:

Enjoy! And please leave comments if you find that this information is not helping to eliminate stutter and lost frames in your HQ35 videos. This is a very new development and I'm far from confident that this is a definitive answer.

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