Converted Videos look Washed Out

[Track]

I'm converting videos I've taken with my Canon T2i, and no matter what file type or preset I choose.. the videos end up looking like their contrast has gone down.

I mean, I'm okay with lower quality, but they just end up looking totally different than what I shot.

Why does this happen?

[jagabo]

How are you comparing? Two media players side by side?

[Track]

Here's a good example:

[jagabo]

Again, how are you comparing? How did you make those sample images? Even the same video file can look different depending on how you view it. Open the same video in two players at the same time. Do they look the same or different?

[Track]

Well, of course they look different. Just as different as those screenshots.

[transporterfan]

What software are you using to convert, and what are you converting to?

[poisondeathray]

The converted video was probably decoded through quicktime at some point by your converting software - it was cropped 1920x1080 and levels are clamped

The "original" screenshot is taken though libav decoder (probably VLC) 1920x1088, and levels are "normal"

[Track]

What software are you using to convert, and what are you converting to?

Handbrake. I've tried every preset.

[jagabo]

Well, of course they look different. Just as different as those screenshots.

If one video played in two players looks different how do you know your converted files are washed out? Maybe it's just a difference in the way you view them. In the way you prepared your sample images. That's why I asked how you produced the sample images.

[Track]

The converted video was probably decoded through quicktime at some point by your converting software - it was cropped 1920x1080 and levels are clamped

The "original" screenshot is taken though libav decoder (probably VLC) 1920x1088, and levels are "normal"

I'm not entirely sure what all that means, but I'm glad you understand it.

So, what do I do?

[Track]

Well, of course they look different. Just as different as those screenshots.

If one video played in two players looks different how do you know your converted files are washed out? Maybe it's just a difference in the way you view them. In the way you prepared your sample images. That's why I asked how you produced the sample images.

No, I'm sorry. I didn't read the question properly.

The same video looks the same, or roughly the same, in both media players.

[sanlyn]

Both images look washed out to me. jagabo's question is relevant: how were the images made? WHile that does have something to do with the way the images "look", it seems IMHO the video was captured with the wrong base-IRE. That could set black levels to0o0 high (the white -- bright -- levels are correct, but gamma is a mess).


[Attachment 16874 - Click to enlarge]

A histogram of your original loos like those I see for video using the wrong base IRE on playback, or or maybe the capture software has such a setting.

[Attachment 16875 - Click to enlarge]

Even at that, you wouldn't correct this by changing "contrast" or making the video "darker", which are both the wrong way to do it. You would ajust gamma to get the correct black levels without wiping out everything else. I changed gamma with the levels control in After Effects (VirtualDub has a similar control), set for broadcast standard at the black levels:

[Attachment 16876 - Click to enlarge]

But the problem is in either the playback or the capture settings. I'd suspect playback.

[Track]

Well, I'm playing it with Media Player Classic. I took the screenshot with MPC, as well.

[sanlyn]

MPC generally takes a snapshot straight from the frame. Still looks like the base-IRE (base black level) is not correct. Brights are a tad "hot" as well, but that's true of most consumer cams. It's minor here and can always be adjusted.

[Track]

MPC generally takes a snapshot straight from the frame. Still looks like the base-IRE (base black level) is not correct. Brights are a tad "hot" as well, but that's true of most consumer cams. It's minor here and can always be adjusted.

Is the T2i considered a consumer-level camera? This particular video was captured with a very cheap mirror lens just as a test run.

Well, it's not MPC because the original file's black level is fine. It's obviously handbrake's fault, no?

[sanlyn]

I used Handbrake briefly a while back, but don't recall seeing a relevant setting for black levels. Haven't used it since because I don't care for the way it cropped. When you say the original's black level looks OK do you refer to playback via TV or directly into a computer without capturing? In other words, does the video play normally before conversion or other processing?

[sanlyn]

Is the T2i considered a consumer-level camera?

This particular video was captured with a very cheap mirror lens just as a test run.

That's a new one. How do you capture a video into your computer with a mirror lens?

Well, it's not MPC because the original file's black level is fine. It's obviously handbrake's fault, no?

Can't say. We don't know how you transferred the original video to your PC. IMHO you seem to have omitted some information.

[jagabo]

This issue (converted video looks different than original) pops up all the time. It's almost always a result of the way the videos are viewed, not a difference in the videos. The video in most compressed formats is stored in YUV. To view them the video has to be converted to RGB on the computer monitor. Media players usually use the graphics card to do the conversion, not the CPU. The graphics card has video overlay proc amp controls for converting YUV to RGB, separate from the Desktop proc amp controls. Depending on the graphics card and the version of Windows only one program at a time can use video overlay. So if you play a single video in two media players (even two instances of the same player), one will get video overlay to convert to RGB, the other will use the CPU and write to the Desktop. If the video overlay proc amp controls are maladjusted (and the defaults in the graphics driver are often wrong) you will see differences in the two players.

What usually happens is someone starts playing the original video, then while it's still playing starts a second instance of the player for the new video. Often the complaint is that the new video looks washed out. But if you repeat the test, this time starting the new video playing first, then the old video, the results are exactly the opposite.

Handbrake doesn't routinely change levels so I wouldn't expect to see a difference after encoding. But I found a vimeo.com page with a sample from the Canon Rebel T2i (http://vimeo.com/9810793). The video is a little unusual in that the luma values (the "Y" in "YUV") run from 0 to 255 rather than the usual 16-235. I wonder if that confused Handbrake. If the camera routinely produces such video it will need some special processing before reencoding. Upload small samples of your source and converted videos and someone will take a look at them.

Another possible issue if you're downsizing is the difference between rec.709 and rec.601 YUV/RGB conversion. The former us usually used for high definition video, the latter for standard definition. If you're downsizing to DVD resolution you should also convert from rec.709 to rec.601. The differnece is usually pretty subtle, most visible in greens and reds.

Also, as someone mentioned, Quicktime is notorious for screwing with levels. So if Quicktime was used in the decoding that could be problem.

[transporterfan]

Just to throw a spanner in, I have only used Handbrake twice and never liked it.
I stopped using it because the files were incompatible with a device I was using at the time.
In any event, the two encodes I did, the video quality had changed. At the time I thought nothing of it.
I was more annoyed they didn't work than I was at level changes. The OP got me thinking and I went back to the Handbrake site.

https://trac.handbrake.fr/wiki/PictureSettings

And discovered that it does employ filters. If a program does that surreptitiously then all bets are off as to who is right and wrong. I am not sure what it filters or how it employs them but have read a couple of reports on other blogs today of other people feeling the same about their video quality being altered.

[jagabo]

Well, I'll be! I just tested Handbrake with the sample from the above vimeo.com link and indeed it "legalized" the luma levels to standard rec.709. This would explain why you are seeing the washed out video. But notice how you can see more detail in the darks and brights in the converted image, they aren't blown out. Original on the left, handbrake encoded on the right (I downscaled the 1080p sources for these snapshots):



Does this mean Handbrake is automatically converting xvYCC to rec.709?

[transporterfan]

@jagabo: nice comparison!

@Track: Yes. Handbrake can seriously alter your video. Try a different converter.

[jagabo]

@Track: Yes. Handbrake can seriously alter your video. Try a different converter.

But in this case Handbrake did what it's supposed to do, converted wide contrast (Y 0-255) to standard contrast (Y 16-235). I don't really use Handbrake but I'm going to try some experiments to see what it does with other files. I want to know if there is some kind of "full range" flag in the MP4 file or if it looked at the video, saw the out of range values, and squeezed them.

[transporterfan]

@Track: Yes. Handbrake can seriously alter your video. Try a different converter.

But in this case Handbrake did what it's supposed to do, converted wide contrast (Y 0-255) to standard contrast (Y 16-235). I don't really use Handbrake but I'm going to try some experiments to see what it does with other files. I want to know if there is some kind of "full range" flag in the MP4 file or if it looked at the video, saw the out of range values, and squeezed them.

I agree. I do a lot of photography, not a lot of video. If software does 'what it's supposed to do' and not what I want it to do it is of no use. In this case (probably because of my other hobby - I prefer high contrast images) I would be happy with what it produces. I never said I don't like Handbrakes output, only that it changes said output.

[jagabo]

I reencoded the T2i sample video (opened with ffVideoSource() in AviSynth) with x264 CLI, making an MKV file. The MKV video retained the same full range luma. I then converted that file with Handbrake. The Handbrake encoded file retained the full range luma. I repeated the experiment using an x264 encoded MP4 file instead of MKV. Handbrake kept the full range luma again.

So it appears there's something in the original MP4 file that flags the video as full-range. Apparently Handbrake sees that flag and reduces the range to standard rec.709 when it converts.

[Track]

I reencoded the T2i sample video (opened with ffVideoSource() in AviSynth) with x264 CLI, making an MKV file. The MKV video retained the same full range luma. I then converted that file with Handbrake. The Handbrake encoded file retained the full range luma. I repeated the experiment using an x264 encoded MP4 file instead of MKV. Handbrake kept the full range luma again.

So it appears there's something in the original MP4 file that flags the video as full-range. Apparently Handbrake sees that flag and reduces the range to standard rec.709 when it converts.

Thank you, jagabo.

I can honestly say that I think I'm understanding most of what you've said.

However, I really doubt that I would be able to use a CMD video encoder.. is there another option?

[Track]

Bump..?

[brusno]

However, I really doubt that I would be able to use a CMD video encoder.. is there another option?

You may try StaxRip

[jagabo]

XMediaRecode did the same contrast reduction as Handbrake. An older version of Xvid4PSP (5.0.37.8) kept the full range luma. But that may end up causing a problem with playback. If your player sees the full range flag in the original video and compensates during playback, it won't see such a flag in the Xvid4PSP converted video -- the blacks and brights will be crushed. What do you see when you play the original video? At about 19 seconds into the video:



On the left you can see that the pattern in the dark jacket has disappeared. The highlights in the woman's hair are blown out. If your player is compensating for the full scale luma you will see something like the image on the right. But after conversion you may see something like the image on the left.

[Track]

When I play the original video, that is exactly what I see - certain parts are dark, almost black, making it hard to see the detail.

Is that because MPC is compensating? Then how will it look if it does not?

It seems like I have to choose between that and a washed out image..

[Track]

Bump