youtube + x264 + 640*480 = weird artifacts

[10L23r]

I have this problem where if i upload a x264 video with resolution 640*480 to youtube, a lot of resolution is lost.

Refer to this link for more details:
http://grumbel.blogspot.com/2010/07/youtube-quality-problems.html
(this person has the exact same problem!)

[AlekseiV]

Have you tried remuxing it as an FLV and uploading it?
ffmpeg -i file.mp4 -vcodec copy -acodec copy file.flv
That page talks about re-encoding the video with Flash Video in FLV, but I wonder if just using the container will work, seeing as how YouTube isn't very good with interpreting some containers.

[10L23r]

no i have not... ill try some time tomorrow when i get on my computer. (though i highly doubt it'd do anything)

but i must note that neither mp4 nor mkv containers can fix the problem.

[Yoshiyuki Blade]

It may just be Youtube screwing up the video. I posted pretty much the same issue for 1080p video a while back. Just by chopping off a couple rows (upload at 1078p) fixes the problem. Maybe it's the same issue here.

[ajp_anton]

BTW, since Youtube is widescreen, you can add black bars to the sides of the video (852x480) without screwing with the actual image. Youtube will think the image is bigger and will give it more bitrate.

[10L23r]

nope
doesn't fix the problem

if you read the link, you'll understand that it's not a bitrate problem, but rather a problem with youtube's processing that is specific to x264 when the vertical resolution is exactly 480

[ajp_anton]

I didn't try to answer your question, in fact I didn't even click the link. Just giving a tip to increase the quality once you fix the "weird artifacts" problem =)

Oh and I've uploaded many x264-encoded videos in 480p without any problems. I mux them all into mkv.

[Yoshiyuki Blade]

Adding borders might help YT to create a 480p version of the video if it hasn't already. But again, this is purely a projection based on what I've seen with HD video. A 1440x1080 clip will not offer a 1080p mode (only 720p tops). However, adding 240 horizontal pixels on each side will. Furthermore, there's that little pixel-chopping trick that you'll need to use so it doesn't totally screw up the video. Maybe you can try uploading an 852x478 video and see how that turns out.

[10L23r]

^I am trying that right now. youtube is undergoing maintenance -.-

so far the best workaround for this is to upscale to 960*720...
i guess it improves quality a bit too because afaik hd videos get more bitrate for the 480p mode

[ajp_anton]

Adding borders might help YT to create a 480p version of the video if it hasn't already. But again, this is purely a projection based on what I've seen with HD video. A 1440x1080 clip will not offer a 1080p mode (only 720p tops). However, adding 240 horizontal pixels on each side will. Furthermore, there's that little pixel-chopping trick that you'll need to use so it doesn't totally screw up the video. Maybe you can try uploading an 852x478 video and see how that turns out.Don't know/remember about 1080p, but when I did my YT testing a year ago, 480p worked fine with 640x480.

^I am trying that right now. youtube is undergoing maintenance -.-

so far the best workaround for this is to upscale to 960*720...
i guess it improves quality a bit too because afaik hd videos get more bitrate for the 480p modeWhen I did the testing mentioned above, within each mode (360p, 480p, 720p, 1080p) the bitrate was a linear function of the number of pixels. So for example every 480p video, no matter what the source resolution was, had the bitrate [width*height*c] kbit/s.
Don't remember if I compared different modes with each other... and maybe YT has changed something since then, I should do these tests again.

[MatLz]

(I don't know You Tube)

Maybe they use a 'quality' encode like crf in x264 ?
If they use only one quality value for all resolutions, maybe that is the problem.

Generaly in x264, i think lowres need lower crf value than higher resolution because upscaling resolution on playback......upscale artifacts too....

And sorry for my crappy anggliche :D

[Warperus]

From my tests they don't use pure quality mode. Quality of the image degrades drastically for high complexity scenes.

[TheSkiller]

I have encountered the same problem a week ago. If I upload a x264 encoded video (either as MKV or MP4), YouTube would just throw away every other line of the video and replace it with the previous one. Looks like it's supposed to be a cheap way of deinterlacing.

so far the best workaround for this is to upscale to 960*720...
i guess it improves quality a bit too because afaik hd videos get more bitrate for the 480p mode
This happened not only with 640x480 videos, but also with 960x720, although at 960x720 it is less visible. The only workaround I have found so far is encoding to Xvid AVI...

Videos upscaled to 960x720 definitely look a lot better on YouTube (if watched in "720p" mode) because they get a much higher bitrate for their image size than videos YouTube rates "480p".

[poisondeathray]

Have you considered using other free video hosts ? e.g. vimeo.com

[10L23r]

This happened not only with 640x480 videos, but also with 960x720, although at 960x720 it is less visible.

are you sure? i haven't seen any "deinterlacing" at 720 at all...

[TheSkiller]

Well it definitely happened to a 960x720 x264 encoded video that I uploaded on Aug 17th, it was easy to spot because it was a desktop screen capture. It also happended to a video I uploaded on Aug 2nd. But it did NOT happen to a video I uploaded July 25th. It's weird, it doesn't seem to happen to 960x720 videos every time so I would always carefully check them.

[pasteeater]

I have this problem where if i upload a x264 video with resolution 640*480 to youtube, a lot of resolution is lost.

Show your x264 command and the complete output.

[10L23r]

Show your x264 command and the complete output.

it doesn't matter.
the default settings produce the glitch so...

[Justin101]

no, I have not. Make sure that your video format is flv.OK? If it is not, this problem occurs is normal. And I suggest you that you can use the free video converter factory to solve the problem. Just google it.

[Trahald]

it doesn't matter.
the default settings produce the glitch so...

If you say the default settings produce the glitch then your command line DOES matter. ie. your command line would be x264.exe --output blah.mp4 blah.avi

If you say ANY combination of settings produces the problem, then the command line doesnt matter.

[10L23r]

If you say ANY combination of settings produces the problem, then the command line doesnt matter.

This is what I meant. A 640*480 clip encoded with x264 regardless of settings in either mp4 or mkv container will produce the glitch.

perhaps remuxing the stream could fix the problem... I'll try that tomorrow.