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Old January 27th, 2016, 02:06 PM   #1
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recording bitrate query

For example if a video is recorded h264 and say the bitrate used is 5.500Kbps will it be sharper if recorded a 720p or 1080p when authored to 480p dvd?
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Old January 27th, 2016, 02:34 PM   #2
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Re: recording bitrate query

Hi Bruce,

When encoding a video clip at a fixed bitrate, the lower the resolution, the less pixels to compress, so the 720p should provide the best result since the delivery will be a lower resolution anyway (DVD).

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Old January 27th, 2016, 02:49 PM   #3
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Re: recording bitrate query

yep that's what I figured too
Thanks for getting back to me with that.
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Old January 28th, 2016, 09:53 AM   #4
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Re: recording bitrate query

That seems an odd situation. So far as I know, Jeff is correct in his answer to the narrow question asked.

But, where do you get a 1080p file at 5,500Kbps? A conventional camera is going to lay that down at a minimum of 20-28,000Kbps (28Mbps).

In a properly constructed workflow aimed at best quality, you'll maintain higher resolution and higher bitrates until the last step of encoding for distribution. If possible, that would mean 1080p at 20Mbps + gets encoded for DVD, using a good scaler to get it down to 480p at perhaps 8.5Mbps.

An original 1080p or 720p at 5.5Mbps can be pretty ugly, depending on the complexity of the image (motion, noise), and the quality of the rendering codec. Generally, you'd want to avoid such a low spec as an intermediate or master render. That's a quarter of the bitrate typically used for 1080p, and maybe a third of what's typical for 720p.
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Old January 28th, 2016, 06:24 PM   #5
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Re: recording bitrate query

Narrow question indeed but to the point n'est pa?
Anyway I'm doing things other than "a properly constructed workflow" what a hoot lol
the little x9 in the picture records the output from the switcher as either mp4 or ts and does a decent job in good light but I cannot adjust the bitrate but can control the resolution - thus the question
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Old January 28th, 2016, 08:14 PM   #6
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Re: recording bitrate query

Quote:
Originally Posted by Bruce Dempsey View Post
Narrow question indeed but to the point n'est pa?
Anyway I'm doing things other than "a properly constructed workflow" what a hoot lol
the little x9 in the picture records the output from the switcher as either mp4 or ts and does a decent job in good light but I cannot adjust the bitrate but can control the resolution - thus the question
Well, you gotta' do what you gotta' do!

If you have good results from the x9 recording, or good enough, well, good enough is good enough!
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Old January 29th, 2016, 07:50 AM   #7
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Re: recording bitrate query

The term workflow as I understand it refers to the post production process whereas In my case production switching is the preferred method as Live Streaming is the primary medium of delivery so any camera cuts, chroma key, titling and pip needs to be done insitu.and the bitrate referred to in this instance is broadcast bitrate: H.264 High, Main, Baseline Profile ( max.720/30p 10Mbps ), AAC-LC ( max.256kbps ) and multi bitrates must also be transmitted from the rtmp server in 240p , 320p,480p to allow lower bandwith viewers unbuffered video
I cut my teeth in Live TV back in the late 60's and it's still a thrill to see a polished production sent out to a live audience. Back then it took a semi trailer full of heavy gear, and a crew of 7. - Today I accomplish the same (if not more complicated productions) one man band with a few devices stuck on a tripod so when you say "good enough" I try to understand where you are coming from and I trust it is not in a mocking tone.
As to the zidoo x9 the android / linux tv box which records the switcher's output via an hdmi port.. Well it is a marvelous little device that cost me less than a hundred bucks, records to a usb3 stick or sdcard and so long as the result is not expected to be "cinema", then the recordings are certtainly acceptable unless the viewer is pixel peeping at 200%. Squeezing evey last drop of goodness out of it as well as all the other budget gear I use is an ongoing and pleasureable chore. thus my initial question
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Old January 29th, 2016, 01:07 PM   #8
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Re: recording bitrate query

Quote:
Originally Posted by Bruce Dempsey View Post
The term workflow as I understand it refers to the post production process whereas In my case production switching is the preferred method as Live Streaming is the primary medium of delivery so any camera cuts, chroma key, titling and pip needs to be done insitu.and the bitrate referred to in this instance is broadcast bitrate: H.264 High, Main, Baseline Profile ( max.720/30p 10Mbps ), AAC-LC ( max.256kbps ) and multi bitrates must also be transmitted from the rtmp server in 240p , 320p,480p to allow lower bandwith viewers unbuffered video
I cut my teeth in Live TV back in the late 60's and it's still a thrill to see a polished production sent out to a live audience. Back then it took a semi trailer full of heavy gear, and a crew of 7. - Today I accomplish the same (if not more complicated productions) one man band with a few devices stuck on a tripod so when you say "good enough" I try to understand where you are coming from and I trust it is not in a mocking tone.
As to the zidoo x9 the android / linux tv box which records the switcher's output via an hdmi port.. Well it is a marvelous little device that cost me less than a hundred bucks, records to a usb3 stick or sdcard and so long as the result is not expected to be "cinema", then the recordings are certtainly acceptable unless the viewer is pixel peeping at 200%. Squeezing evey last drop of goodness out of it as well as all the other budget gear I use is an ongoing and pleasureable chore. thus my initial question
Yes, we have a similar history in broadcast TV and streaming. It is amazing, isn't it!

"Good enough is good enough" is meant quite sincerely, not mocking at all. To my thinking, there is an endless number of experts on the internet to tell you or me that what we're doing is wrong, because it doesn't meet some standard of what someone else has spent thousands to purchase. Or maybe we have the wrong gear. "Everybody knows that blah blah blah, and I'm doing you a favor to tell you this..." when repeating something read on the internet.

Which leaves producers in exactly the same situation as they've ever been. Somebody has to determine how good is good enough, because every project has some constraint of time, money, gear, or staff that may affect the delivered quality. So, when you say "what I'm doing is good enough..." I tend to take that at face value, because I have no idea as to the needs you're satisfying, nor the constraints you're working within.

Of course there are some recognized best practices approaches to this or that process, too. And I do believe that workflow starts in preproduction, because what we plan and what we execute in production affects our choices and results in post. For a straightforward example, Premiere bogs down previewing some MP4 files, but seems to cruise through AVCHD. That's a workflow choice, I'd better test it out and select AVCHD recording in the camera if I want a good editing experience.

BTW, I had a quick look at the Zidoo x9 specs. What I found is that it's encoding h.265, not h.264, and is capable of more picture quality at a given bitrate than h.264. Which somewhat clarifies (in my mind, FWIW), why you're finding good enough quality at 5Mbps. A different ballgame, I don't have as good a sense of best practices with h.265; I'd want to test out both 720p and 1080p.
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Old January 29th, 2016, 02:55 PM   #9
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Re: recording bitrate query

the x9 in it's Hdmi-In mode is recording h264 either as an mp4 or .ts
It will view / play h265 . alogn with I bunch of stuff I haven't even looked at. Only the hdmi-in part interests
It's variable framerate gives editing software an earache but I think that is one of the reasons it can produce such nice video at very low bitrates. both variable bitrate and variable framerate is quite an efficient process but probably wholey unsuited to much editing other than trim Certainly no grading or fancy stuff. That's why it's so important to get it right during production
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