Search the Help Forum
|
general question about video quality on flickr
|
|
i have just uploaded and then deleted a new video on flickr because the quality was so badly degraded.
the video was of white water over a fall and a heron, taken with a new camera.
downloaded onto my laptop it was very clear and sharp, although it is not HD.
on flickr much was blurry and ugly.
i have often found before that a smooth gliding flow of water, say, when uploaded to flickr becomes broken up by what look like unfocused blocks of pixels floating along - as if the lens were filthy or covered with blotches of grease.
my question is: is this kind of degradation of image inevitable? it is particularly noticable on blocks of colour, and water, when the screen isn't very busy
i hoped my new and better video quality with the new camera would improve things, but it's just as bad....
i don't process videos at all after taking them.
i checked faqs etc. but couldn't find an apt section to answer this...
Posted at 6:03AM, 23 November 2010 PDT
(
permalink
)
ed ed edited this topic 18 months ago.
|
|
|
In the past, when an issue like this has come up, staff has asked users to leave the video in place and provide a link to it, so they can take a look.
If it happens again, I'd recommend leaving it there so others can check it. :-)
Posted 18 months ago.
( permalink
)
|
|
|
yes, that occurred to me after deleting, but it is not just a problem with this one video - i've had the same problem often before...
and the video was so disappointingly ugly in the flickr version that it hurt to look at it!
but thanks for the advice.
Posted 18 months ago.
( permalink
)
|
|
|
p.s. but here's another one that has similar burriness especially at bottom left if you look full size...
www.flickr.com/photos/47246995@N00/5020546893
Posted 18 months ago.
( permalink
)
|
|
|
"if you look full size..."
By "full size" do you mean when I click on the "full screen" button? That size will differ depending on each viewer's monitor size and screen resolution. My monitor is set at 1920x1080, so I wouldn't expect it to look great at that size...
But on the Flickr page, that video looks fine to me (other than being a little dark). I wonder if your browser is zoomed in a little? You can press CTRL+0 to reset your browser zoom. (Just in case that's it.)
Posted 18 months ago.
( permalink
)
|
|
|
I can see that ed ed . The bottom left corner, and for me the bottom right corner (which is worse) look as if they are smeared with Vaseline.
Posted 18 months ago.
( permalink
)
|
|
|
 yes, i meant full-screen. my point being that if i watch it full screen on my laptop after downloading it from my camera it is uniformly sharp....
but even on default fickr page size it is blurry (to me)
 thanks very much. yes, the right is as bad, it's true. smearing is just the word...
it is dispiriting that this happens.
Posted 18 months ago.
( permalink
)
|
|
|
Hi there,
If you could please leave that video in place, we'll be able to take a closer look at it. Until we do, can we get some info from you as the compression used on the videos? So, codec, frame rate, data rate, resolution, and deinterlacing info (if you have it).
Which reminds me that we should make an FAQ as to suggested parameters for those. ;-)
Posted 18 months ago.
( permalink
)
|
|
|
Oh, also to note, the original file size of this video is 640 x 480 , so, it's doubtful that it will ever look great at 'full screen' after being trancoded. Do you have a higher resolution for this file?
Posted 18 months ago.
( permalink
)
|
|
|
 this is the only resolution i have for this, i think. i just transfered it from card to computer and then uploaded that file to flickr.
my latest video which had the same blur, if not worse, this time on white water, was 848X480. and the original was fine on my screen.
i have an HD mode available on my camera, but don't see the point of using that if the flickr quality is so poor.
i suppose what i need to know is whether a sharp deterioration in quality is inevitable in the transcoding process.
and if there is any way to avoid blurring/smearing in the process.
as i have said, on my laptop screen the videos are without this blurring effect
i am afraid i have no idea what deinterlacing means let alone how to find out about it....
Posted 18 months ago.
( permalink
)
ed ed edited this topic 18 months ago.
|
|
|
Hi ed ed,
We see the original file is encoded at 11MBps; since for SD video we transcode at a bit rate of 694Kbps, artifacts can be expected during our transcode process since we're stepping the video down (11MB > 694Kbps). So, it might be a good idea to use video editing software (such as Windows Movie Maker, which is free for Windows users) to compress the video using a lower bitrate.
If you did record video in HD, we do use a higher bitrate during the transcode (2MBps), so that is one benefit of recording in HD (and we have the ability to transcode at 4MBps, too, here).
Unfortunately, that particular type of video (mostly black and shadows, moving water) will show any compression artifacts more than a different subject, but yes, there can be a decrease in quality during transcode depending on the tech details of the video uploaded.
A rough rule of thumb (which we can add to the FAQs), is the following:
- Encode no higher than 2MBps for SD, 5MBps for HD
- use H.264
- use 30 frames per second
- use deinterlace
Posted 18 months ago.
( permalink
)
|
|
|
yes, good idea to put something in the faqs.
make it as simple as possible though, because many - like me - are pretty shaky when it comes to bitrates etc.
i'll try using the hd mode in future to see if the result is better, but the video i uploaded and deleted today (not hd, but v. good quality on computer) was mostly bright white turbulent water over a weir and the white foam looked smeared and blurry, even though it was pretty well lit.
it's a pity water doesn't come out well, as it is one of the most dramatic and varying of subjects for a "long photo."
i'll google deinterlace as it means nothing to me, but i guess that is something you could do on the movie maker editor?
anyway, thanks for your response. appreciated.
Posted 18 months ago.
( permalink
)
|
|
|
Interlacing is the practice of only updating alternate lines in the image each cycle; televisions cope well with it (and CRT ones actively benefit), computers generally don't like it much and need to 'de-interlace' video by generating a version where each frame updates completely each time.
If you see video modes described as (for example) 1080p vs 1080i, the latter would be interlaced, the former would be 'progressive', or, more simply, not interlaced. So, if you can set your camera to a mode that records progressive video to start with, and leave it progressive, so much the better.
Posted 18 months ago.
( permalink
)
|
|
|
 i don't think i can do that with my camera though. it doesn't seem to have that option...it has avchd and motion jpeg in three different qualities but i see no p or i...
thanks anyway.
Posted 18 months ago.
( permalink
)
|
|
|
in case this thread is still being looked at by zyrcster, i posted a video today taken in hd mode on my camera as suggested and the edges of the frame are still very blurry and smeary (see top left) compared to the same video shown on my computer.
and there is no dark water this time.
it is straight out of the camera.
i don't know if this is an interlacing problem or what, perhaps it's just what i have to accept as flickr video quality?
Posted 18 months ago.
( permalink
)
ed ed edited this topic 18 months ago.
|
|
|
Hi ed ed,
Again, straight out of camera is probably going to have a very high bitrate and since we transcode at 2MBps, you can imagine how stepped down a 'raw' video straight from the camera is going to be.
If you post a link, we can take a look and walk you why it's looking compressed.
Again, you'll have best results uploading to our service (and, in fact, most other video sites) if you process the video prior to uploading, following the info in my comment above.
Posted 18 months ago.
( permalink
)
|
|
|
sorry, i forgot the link;
www.flickr.com/photos/47246995@N00/5214285622/
i'm afraid i don't much understand the language of video editing. i just occasionally upload a video. it's not something i want to spend a lot of time on, but i'll look into it.
curiously, with my videos the smeariness seems to be worse now than it used to be...(esp. noticeable in top left of this video)
do you think it would be better to use the less-than-best quality in the camera setting or the hd one? - i can't see much difference as far as the degradation is concerned...
thanks.
Posted 18 months ago.
( permalink
)
ed ed edited this topic 18 months ago.
|
|
|
Hi ed ed,
Thanks for the link. The bitrate on that video is 30MBps. We transcode all HD videos at 2Mbps. So, we're stepping your upload down from 30MBps to 2MBps. That's going to significantly affect the quality of the video, so you should get the bitrate down yourself prior to uploading, using video software.
I should also note that the type of compression artifacts you're seeing directly relate to the subject matter you're shooting (not that you should shoot other subjects, but if those are the subjects you're shooting, you should get familiar with video editing software!)
Also, the original of that video is 1280 x 720. When we transcode the videos, we're resizing them to 640 on the longest side. So, that's also going to affect the quality.
If you instead edited the videos yourself and then upload them, they'll get through our processing probably looking a lot better than they do now. On Windows, you can use their free Windows Movie Maker to convert the videos , using the settings I describe above as your maximums, and then upload it to Flickr.
This group can probably provide some advice, too:
www.flickr.com/groups/moviemaker/
This topic has some good info (noting that we now go up to 640px on the longest side, not 500, so you can adjust that accordingly).
www.flickr.com/groups/moviemaker/discuss/72157608106226196/
Posted 18 months ago.
( permalink
)
|
|
|
o.k., well many thanks.
does the longest side business mean that it would be better to shoot the original video in 640x480 then?.
it seems to be on this kind of "long photo" video that the degradation is most evident, as opposed to,say, people walking down a street...or moving the camera around...
i don't have windows movie maker but can download it: it depends how long i have to spend on editing video, which is not my speciality interest.
do you think the transcoding process you use will get "better" at some point?
anyway, i appreciate your help. thanks again - and for the links.
Posted 18 months ago.
( permalink
)
|
|
|
It does sound like there's a serious problem at the Flickr end - if it's possible for us to get videos down to suitably low bitrates without them looking rubbish, it should be possible for Flickr too.
Edit: Also, what's with this '640px on the longest side' idea? According to the FAQ, pro account holders should be able to get 720p, which is 720px vertically, and a decent number more across.
Posted 18 months ago.
( permalink
)
|
|
|
Cris, I have a question about the best settings. You mention that you transcode HD videos at 2Mbps and to 640 on the longest side.
But if I resize my HD vid to 640 on the longest side, will you still see it as an HD video, or will you treat it as an SD video and then use a bitrate of 694kbps?
I guess I'm a bit confused what I should do with my HD (1280x720) videos. Lower the bitrate to 2Mbps and then let Flickr resize it to 640? Or resize it myself to 640x360 at 2Mbps and then have Flickr downsample to 694kbps. How does your program decide a video is HD? I thought it was based on dimensions.
Posted 18 months ago.
( permalink
)
|
|
|
Hi ed ed,
We might kick up the bitrate some, but that does result in very large files, which would impact how viewers perceive playback, so it's doubtful we'd transcode to 30MBps any time soon. It's a tradeoff, more of which is discussed here:
en.wikipedia.org/wiki/Video_compression
Posted 18 months ago.
( permalink
)
|
|
|
well, i did as suggested, found a video editor, changed the parameters of the video in 2 different ways as 2 separate tests, set frame rate to 30, tried the bitrate at 2mbps and then 512kbps, changed size to 640x480 (shows a black strip at top because of different proportion height to width, i guess) then 720x480 - (proportion ok in a black frame.)
these changes reduced the size of the file from around 100mb to around 16 mb, so it is evidently of poorer quality.
uploaded both separately to flickr:
result: smearing and blurring just as bad, possibly worse.
(as i said original video from camera crystal clear on computer)
time to give up?
Posted 18 months ago.
( permalink
)
ed ed edited this topic 18 months ago.
|
|
|
Hi ed ed,
Try searching for video groups on Flickr (or the internet in general) and asking other members how they produce good quality video for online services.
www.flickr.com/search/groups/
Good luck!
Posted 18 months ago.
( permalink
)
|
|
|
Cris, I'm wondering if you missed my question above, as I posted it at the same time to your reply to ed ed.
Posted 18 months ago.
( permalink
)
|
|
|
Hi Brenda & The Ewan,
I'll ask one of our developers to explain the dimensions and address questions about the bitrate issue, so thanks for your patience.
[edited for grammar]
Posted 18 months ago.
( permalink
)
zyrcster (staff) edited this topic 18 months ago.
|
|
|
the following streams are produced for sharing at flickr (besides mobile and appletv ones)
a) 640x480@700kbps h.264, mp4 container (90sec) (that is ~2.30 bitrate/pixel ratio)
b) 1280x720@2Mbps (90sec) h.264, mp4 container, if video is 720p+ (that is ~2.20 bitrate/pixel ratio)
HD video in our case is higher resolution though quality will be lower comparing to 640x480 that has better bitrate/pixel ratio (more artifacts, i.e. more big blocks in case of lower ratio). we are working on transcoding quality issues and planning to change default bitrates.
recommended video settings:
* 640x480 SD or 1280x720 HD
* bitrate: 1000-2000kbps for SD, 3000-4000kbps for HD. AFAIK, we don’t do any video pre-processing (noise reduction etc.), thus video with high bitrate and lots of noise (small moving parts) will have more artifacts after transcoding.
* Deinterlacing - use progressive mode (check camera settings), always deinterlace.
* frame rate: 25 or 30 is nice, this makes video playback “smooth”, though consumes bitrate, i.e. lower framerate might improve picture quality but affects playback.
Posted 18 months ago.
( permalink
)
|
|
|
Thanks. Now I can set up an iMovie export preset. :)
Posted 18 months ago.
( permalink
)
|
|
|
 this is all getting a bit beyond me, but please note that the changes i made on advice from staff - 6 posts above - made no difference to the final flickr result, and if anything made the result worse.
Posted 18 months ago.
( permalink
)
|
|
|
Hi ed ed,
Alex (shurikk, who is one of our develoeprs) just posted the (at this time) current "best practices" one should follow for best results uploading video to Flickr.
Lengthy discussions on how video compression work are really beyond the bounds of this Forum, so we do encourage you to seek video advice from other video members in video groups or at least try out the video editing software and encode to the suggestions that Alex posted above rather than posting straight out of camera.
www.flickr.com/search/groups/?w=all&q=video
Posted 18 months ago.
( permalink
)
|
|
|
i shall bow out of this discussion now.
the point i was making was that i did use editing software on your advice and did edit the video using the guidelines i had been given for better results, which were similar to's list, but that the editing didn't make things any better at all, but in one case much worse;
i.e that the editing advice, while taking some time, doesn't necessarily work.
Posted 18 months ago.
( permalink
)
|
|
|
Hi ed ed,
Thanks - if we can see a video you processed to the suggestions, we can take another look at it to see if we can improve things. Thanks!
Posted 18 months ago.
( permalink
)
|
|
|
I'm guessing that where a camera has 'quality' (essentially bitrate) settings it might be worth using the camera in 720p, 30fps, low quality, mode, then trying to upload that directly since it might have a similar effect to reducing the bitrate in editing software. No good if you want a low bitrate copy for Flickr and a high bitrate one for elsewhere though.
And still doesn't explain why individual users should be able to do a better job of transcoding the video than Flickr can. In principle it should be best to start off with the highest quality you can and transcode it once to the low bitrate web version. If you can get better results by transcoding it once, then transcoding it again from the already reduced quality result from the first step, there's something odd going on.
Posted 18 months ago.
( permalink
)
|
|
|
this is very late, but i was wondering the same - if a video recorded at lower quality in the camera might be better for the flickr transcoding process, than a video recorded at a higher quality.
in fact my newer camera, which can produce better quality video than my previous one (same make etc.) seems to result in worse quality on flickr video than the old one...though better on my computer screen.
perhaps as you suggest, i should set it on low quality for recording video for flickr, which seems paradoxical, not to say nuts.
Posted 18 months ago.
( permalink
)
|
|
|
I must say Flickr Flash quality is worse than YouTube and much worse than Vimeo.
Hope this will be improved one day.
Posted 18 months ago.
( permalink
)
|
This thread was closed automatically due of a lack of responses over the last month.
|
Feed – Subscribe to help discussion threads