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-   -   1080p youtube test (https://www.dvinfo.net/forum/avchd-format-discussion/469685-1080p-youtube-test.html)

Robert M Wright January 18th, 2010 12:24 PM

I experimented with that other video (the one in a casino), and basically got the same visual quality (perhaps slightly better) at 720p using a little lower bitrate (720p around 3.5Mbps vs YouTube's 1080p at about 4Mbps). To achieve the quality I got though, I did some serious pre-compression filtering and used encoding settings that almost assuredly would not be practical for YouTube to use on a massive scale. It looks like perhaps YouTube is using a very brute force approach (really fast motion estimation, etc.), probably to make transcoding ultra fast. Given the massive numbers of videos they host, that probably makes sense economically. If they did what I did, with all their videos, they'd probably have to fill an office building with fast computers, and hire a small army of techs that are pretty knowledgeable about video compression. I do think that if they threw that same 4Mbps (using the same encoding parameters) at 720p instead of 1080p, it would look just as good though. In my experimenting, it was quite clear they didn't achieve any finer detail in the images at 1080p than can be achieved at 720p.

Erik Phairas January 19th, 2010 08:19 PM

I haven't tried encoding a video in 720p using the same codec I used for the 1080p videos. I suppose I should give it a try.

I can see the difference in my 720p mp4 and my 1080p mts video on youtube but only just.

Bryan Sellars January 26th, 2010 02:29 PM

Quote:

Originally Posted by Tony Neal (Post 1466058)
Out of curiosity I've just loaded my first YouTube clip in 1080p and was pleasantly suprised at the quality - looks very close to the original if a little stuttery.

It was encoded in h.264 VBR at a target bitrate of 15Mbps - I guess I could try dropping the bitrate to make the playback a bit smoother but maybe YouTube re-encode clips to a bitrate suitable for streaming - anybody know for sure ?

YouTube - Trafalgar 200 HD.mp4


I just use WebVideoCap capture and then used G-Spot to read the file and it came up with this,

Codec: mp4a: MPEG-4 AAC LC
44100Hz 124 kb/s tot , stereo (2/0)
1920 x 1080
kbps 3285
29.971

I only captured the last part of the video in 1080P, so it was only a small sample.

Trent Briles January 26th, 2010 08:29 PM

Need help/Sorry if this is the wrong forum
 
Hi all,

I need some help and I apologize if this is the wrong part of the forum. I know this has been discussed already and I have followed most of the instructions, but it's not working.
I'm trying to upload a video to see if it will display in widescreen format on youtube. Right now, I don't care about the quality; I just want to see if it will work. I'm still getting the bars on the left/right.

my video is SD, but rendered/produced in 16:9 setting and 640/360 (just playing around) I've also saved it in 1280/720 and YT still displays it with the bars. I've even downloaded a small HD video and attempted to upload it with the same results. I have used SUPER Video converter, CinemaForge, and two other software programs and nothing works. My editing software is Premiere. (when you play these videos in QT and WMP it reflects the size of the video settings above).

Any information would be appreciated. Again, I dont care about the quality...I'm trying to get the procedure right.


Thanks much!

Graham Hickling January 26th, 2010 09:31 PM

Quote: my video is SD, but rendered/produced in 16:9 setting and 640/360

I'm confused - it's SD (i.e. 4:3) but you are rendering to 640 by 360?

So your rendered footage must be either a) stretched horizontally, b) pillar-boxed (i.e. black bars left and right), or (c) missing the upper and lower parts of the original image, or (d) has non-square pixels so that it still plays back as 4:3 in mediaplayer.

The only one of those options that will give you correct-looking 16:9 footage on Youtube, without black bars, is option C. Is that what you are uploading?

Trent Briles January 27th, 2010 08:16 PM

Sd
 
Graham,

I sent you an email reference my question. Thanks for the time.

Bruce Phung January 31st, 2010 04:13 PM

Can you really tell the difference between 720P and 1080P? I can't. I try out to upload 1080P and it finished upload to Youtube and the processing take forever to complete, 2 minutes video go an hrs and still processing. I'll stick with 720P.

Tom Gull January 31st, 2010 05:34 PM

Quote:

Originally Posted by Bruce Phung (Post 1479918)
Can you really tell the difference between 720P and 1080P? I can't. I try out to upload 1080P and it finished upload to Youtube and the processing take forever to complete, 2 minutes video go an hrs and still processing. I'll stick with 720P.

I tripped across a freight train video yesterday in 1080p and 720p. The difference was extremely subtle, mostly coming across to me as a slight difference in brightness (go figure). The higher-res one stuttered some even though I have a fast PC, FIOS, and a video acclerator download product in place. Bottom line for that video: no significant difference visually, performance hit for going with the higher-res one.

Martin Labelle February 2nd, 2010 11:21 PM

I can't tell the difference between 720 and 1080, also my Macbook pro is not able to play a clip in 1080(don't play smooth).
But the videos of Erik could only be upload in 480 and a lot of people would not see the difference between 480 and 720.
but there is a big difference in the sound quality.

Erik Phairas February 7th, 2010 09:08 PM

Wait are you making fun of my videos or of youtubes transcoder? :D


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