I have some DV footage 720x576 5:4 ratio (similar to 4:3) Lower Field and created a sequence which I matched with source.I want to upload this to YouTube.
I understand YouTube accepts 720p, in which I use the preset YouTube export (H.264 - YouTube HD 720p 25), which adds black bars to the sides and exports out at 1280x720 Progressive. This takes approx 3 hours to export for a 45min clip.
To speed up the export I tried preset, H264 - PAL DV Widescreen, set to Progressive. By default this uses 16:9 pixel ratio, it added bars to the sides and outputed 720x576. The export took 30minutes only, a lot quicker than the above option. When I play it back with VLC, the overall ratio is correct (i.e. black bars on sides and not stretched), no obvious concerns. I uploaded this to YouTube and it appears fine also.
But as I used frame resolution of 720 x 576 which is 5:4 and it is displayed 16:9 by using non-square pixels, is there a problem that I haven't yet discovered? - Especially, as i keep reading to use square pixels for monitors/YouTube.
Just want to be sure before I continue down this path. Thanks
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720*576 is only the Sample/Storage Aspect Ratio. DV is either displayed as 4:3 (768*576) or 16:9 (1024*576)
If you want to upload 720p 4:3 you can avoid your own side-bars by encoding as 960*720. Then you can be certain that your footage really is 4:3 and not 5:4.
Youtube may stil (and probably will) re-encode and add more side-bars to make the 1280*720 but the footage should still be pure 4:3
Do not upload as 720*576. There is no guarantee that yt's encode acknowledges the AR flag - not even certain there is one in a DV.avi (normal avi does not have one)
Normal AVI V2.0 has facility for one, but is inconsistent so is never used. DV does have facility for one and is consistent in how it is applied. Unfortunately, apps are all over the map of inconsistency for support of AR, even when it is correctly supplied, so agree for most web use* is best to avoid the issue altogether by using square pixel ratios.
*other uses, such as DVD, BD do have consistent playback support of non-square AR.
Visually 5:4 as you pointed out is not dissimilar to 4:3. To confirm that you have not been duped, do a screen-cap of your 1280*720 and then crop away the side-bars. Then do the maths on the active video screen.
To be clear, 720x576 and 720x480 are NEVER 5:4 or 3:2 (respectively), except if you assume a 1:1 pixel AR (aka square pixels). For DVD or DV video, that is never the case - they are always non-square (aka anamorphic), whether 4:3 or 16:9 DAR.
It's only with the primacy of lcd displays and with web playback that square pixel formats are the assumed fallback. IOW, non-square was the rule, now it is the exception to the rule.
I found that youtube process videos quickly and uses less compression if they are 1080p, So I started resizing all my uploads to 1440x1080 whether it be DV/DVD (720x480, 720x576) or analog tape captures (704x480, 704x576), Plus all TV's and computer monitors are at least 1080 in resolution so that will prevent another upscale done by TV/PC from 720 to 1080. You should give it a try and see for yourself. 720P made more sense when we had 720P TV's and monitors, not anymore now.
Thanks for all your inputs!
I think my 1st priority us to reduce my encoding time and maintain quality of original footage. Encoding at 720p takes a long time, so I wonder ho long 1080p will take - i will try.
If I reencode to 960x720, what should I set the Pixel ratio to ? (I'm using premiere)
In my OP, I explained that I can obtain a 16:9 frame ratio if I encode at 1280x720 but why do I also get a frame ratio that is 16:9 when I instead use a pixel ratio of 16:9 ?
1280x720 with square pixels IS 16:9 DAR. But so is 1920x1080.
You aren't using a Pixel AR of 16:9 in Premiere, though, you are using a Display AR. For either of those 2 dimension options above, your Pixel AR is 1:1 (aka square pixels).
If you re-encoded to 960x720 or 1440x1080 using similarly square pixels (aka 1:1 Pixel AR), you would arrive at 4:3 Display AR. Which is very likely what your original material was supposed to be (since you said YT or Premiere added black pillarbars).
So, I recommend you try test encoding to:
- 720x576 at non-square pixel AR (~1.066666:1)
- 768x576 at square pixel AR (1:1)
- 960x720 at square pixel AR
- 1440x1080 at square pixel AR
Every one of them should give you a 4:3 DAR image with black pillarbars when shown in a 16:9 player window or when shown fullscreen on a 16:9 monitor.
If #1 doesn't show that way, it's because the player is not honoring the non-square AR.
Then you pick which one looks best to you. If you have no problem with either the AR or the quality of #1, it is the least change from your source, and is the most efficient in terms of pixel geometry, but my guess like those of the others is that for most web use, you'll end up getting the best quality from #4, even if it takes a while to encode - BECAUSE YT gives it preference when re-encoding (remember, it ALWAYS re-encodes).
YouTube takes the DAR into account for MPG or VOB upload. I've uploaded 720x480 MPGs before and they've been resized to 640x480. I don't know for sure, but doubt they'd do the same for DV AVI.
Last edited by manono; 13th Oct 2020 at 15:54.
I also read somewhere that YouTube will downscale resolution of 720x576.
How can I check what resolution / bit rate youtube has encoded at ? - I could not see anything in the control panel.
You can quickly check the resolutions by checking 'quality' from the settings. To check bitrate you will have to physically download the video.
How about a link ?
Great, This is what I found:
Video exported as 720 x 576 with Premiere set to Square 1.0 or PAL 1.0940 - On YouTube, displayed as 4:3, Available Quality - 144p, 240p, 360p, 480p
Video exported as 720 x 576 with Premiere set to Non Square PAL 1.45 - On YouTube, displayed as 16:9 with bars, Available Quality - 144p, 240p, 360p, 480p
Video exported as 1280x720 with Premiere set to Square - On YouTube, displayed as 16:9 with bars, Available Quality - 144p, 240p, 360p, 480p, 720p
Video exported as 960x720 with Premiere set to Square - On YouTube, displayed as 4:3, Available Quality - 144p, 240p, 360p, 480p, 720p
Seems that option 3 is best, though it takes a long time to render.
Ok. But can we get a link for Option 3 ? I still, and am sure I am not alone, want satisfaction that you really do have 4:3 video in that 16:9 frame
Confirmed that the active video is 960*720.
I'll be asking another question about render speed shortly
Well you can do a test between rendering at 960*720 and 1280*720 with the same bitrate - 960 should be quicker. And yt might give that less bitrate in its re-encode but that should not impact on delivery quality.
But if you want to do a short sample encode/upload, and also upload the original as provided to yt as an attachment here then we can also compare. A 45+ min vid albeit on a topical subject (gotta be careful here since it is somewhat political) and a 9gb original is a compare that most would not attempt.
I am probably wrong with this since much water has flown under the bridge but I seem to recall that 4:3 uploads (my own included) were originally presented pillar-boxed. Now they are presented full-screen with the actual screen width being shrunk to fit.
These days we get used to the 'tv effect' on non-ws material so the bars may not appear out of place. And they did not bother this viewer of the OP's sample.
The downside is the probable increase in encoding time.
Did you try 1440x1080? it is the least damaging resize of all.
What is the best time to resize in the work flow? In AviSynth (BilinearResize) or the last step with Virtual Dub before output?