HD Output and Workflow Queries

[Angelo Lorenzo]

“Am I completely missing an important step or a miracle output format that will unlock the incredible quality of HD? Because as of now, sadly, it doesn’t look much better than SD to me.”

You are because you’re still outputting VGA resolution. Youtube and Vimeo can both take HD files up to 1080p/i

Your technical details are very confusing, and you may have mismatched something.

1. “Shot 1080i HDV 24p on a Sony”… so is the footage 1080i60 or 1080p24?

2. “Captured via firewire in Premiere CS4 on a HD 1080 (60i) timeline”… I would worry if this matches your footage or not based on the poor information in #1. It’s best to match the timeline and capture exactly to your native footage.

3. When exporting you need to choose progressive/no fields. You may also want to choose “blend frames” as this will blend interlaced fields a bit more than not choosing it. Web content almost always looks better progressive and although 1080i looks good, for video sites with multiple resolutions, I don’t know if I’d trust their resizing to account for interlacing (I’ve yet to do tests).

4. With h.264 you can choose the keyframe distance and the bitrate. Less motion = keyframes farther apart and a little less bitrate, more motion = keyframes closer together and a little more bitrate. You can also do VBR once you set your keyframe amount properly. I prefer setting my keyframes manually rather than setting them auto.

The biggest boon to this video is the really high compression. You may also want to throw a sharpening filter on the entire video to retain details as you downsize from HD to SD. Sharpening simply increases the contrast around edges.

– Angelo Lorenzo
– https://FilmsFor.Us Helping you sell your film online

[Joe Boyle]

Thanks for your quick reply!

“… so is the footage 1080i60 or 1080p24?”

Sorry about that. I was a bit confused. The footage is 1080p24.

“… I would worry if this matches your footage or not based on the poor information in #1. It’s best to match the timeline and capture exactly to your native footage.”

I’ve read that if I shoot 24p, I should edit it in a regular 60i timeline and if I shoot 24a, I should edit it natively in a 24p timeline. Is this correct? I’ve also read that it’s only really important to edit 24p natively if my end goal is a film out, which it isn’t. So, which would be better? Shoot 24p and edit it on a 60i timeline, finally ouputting to a 1080i file or shoot 24a, editing it on a native 24p timeline and outputting to 1080p?

“4. With h.264 you can choose the keyframe distance and the bitrate. Less motion = keyframes farther apart and a little less bitrate, more motion = keyframes closer together and a little more bitrate. You can also do VBR once you set your keyframe amount properly. I prefer setting my keyframes manually rather than setting them auto.”

What is the best way to choose the target bitrate? Simply the size of the end file. A higher bitrate target will always result in a higher quality compression, correct? Also, what is a standard place to start testing keyframe distances? 30? 60? It just seems like there is such a wide swath, it would be difficult to pinpoint where to start.

Also, what do you think is the best codec/settings to use for a proper compression of hdv with good final results? H.264?

I uploaded the video once again using your advice about going above VGA standards. Here it is: https://www.youtube.com/watch?v=gnzlwwEAuHg Does it look better?

You have helped me immensely thus far. I hope all of this makes sense. Learning this is difficult for me, but I’m thankful to have some guidance along the way!

Joe

[Jeff Pulera]

Hi Joe,

You are correct that Sony HDV 24p has pulldown added in-camera and is actually recorded to tape as 60i, so you’re using the correct edit preset at 1080 60i.

As suggested, output as Progressive, and tick a “deinterlace” button if you see one, don’t remember what CS4 offers in the output dialog. The “Maximum Render Quality” button can be helpful also, especially if scaling the video to a smaller size.

Regarding output at 640×480 – web video should always use square pixels to avoid a stretched look, so the proper sizing of “SD” output for the web from an HD source would be 854×480 with 1.0 Pixel Aspect Ratio, to maintain the correct widescreen look. Or you can use whatever dimensions you want, but keeping the 16:9 relationship between the two numbers.

Jeff Pulera
Safe Harbor Computers

[Angelo Lorenzo]

Taking Jeff’s answers into account, I would capture at 60i since your camera is adding a pull-down.

You can then do two things: keep your timeline in 60i or, for the sake of having native progressive footage, you can use a 24p timeline. One word of advice: When you are creating a new sequence, under the “Settings” tab click “Playback Settings…” and try each of the two 24p conversion methods (either repeating frames or interlaced) to see what works best with your camera. I would try this setting with some quicker moving footage like pans.

As far as encoding bitrates and keyframes, here are my medium-high recommendations (this assumes 24p, 30p, or 60i):

Low movement/action 640×480:
Keyframe every 15 frames
2000-2500 kbps

Action 640×480:
Keyframe every 8 frames
2500 kbps

Low movement/action 720p:
Keyframe every 15 frames
5600-7500 kbps

Action 720p:
Keyframe every 8 frames
7500 kbps

Low movement/action 1080:
Keyframe every 15 frames
12000-16000 kbps

Action 1080:
Keyframe every 8 frames
16000 kbps

– Angelo Lorenzo
– https://FilmsFor.Us Helping you sell your film online