Anyone notice choppy dvd playback on 360?

M

munkle

[H]F Junkie
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when i play dvd's i notice some nothing major but some slight choppyness during computer generated scenes i dont know why but its only during those scenes and the audio is fine its just the video, i dont know if its the disc because its brand new (lord of the rings extended edition) and never been played before. anyone notice anything like this, its very very slight choppyness?
 
To tell you the truth I haven't even tried playing a DVD in mine yet. I'll try to play one sometime tonight or maybe tomorrow and post my findings back here.
 
During "CGI" scenes suggests that it's choppy during high-bitrate scenery, so maybe its playback is software-based instead of hardware-based.
 
steviep said:
During "CGI" scenes suggests that it's choppy during high-bitrate scenery, so maybe its playback is software-based instead of hardware-based.
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you are kidding, right? its a DVD, its not rendering anything, computer generated or not.
 
I'm not talking about rendering. Are you familiar with the concept of decoding?
 
KingPariah777 said:
you are kidding, right? its a DVD, its not rendering anything, computer generated or not.
Click to expand...
rofl.gif
That's a good one.
 
The 360 is most likely using a combination of the ATI graphics chip + CPU.

If the DVD gets choppy it's most likely the software or the DVD drive loading speed.
 
steviep said:
I'm not talking about rendering. Are you familiar with the concept of decoding?
Click to expand...
What the hell does CGI on a movie have to do with decoding?

Its all video to the player...

PerfectCr said:
rofl.gif
That's a good one.
Click to expand...
glad you liked it. Care to contribute?
 
KingPariah777 said:
What the hell does CGI on a movie have to do with decoding?

Its all video to the player...


glad you liked it. Care to contribute?
Click to expand...


:confused:

CGI has nothing to do with decoding.. just the AMOUNT of information that is being displayed does. CGI scene might have more information thereby having a higher bitrate at that point to show the appropiate information.

DVD do not render. They get decoded from the MPEG serial stream to either digital or analog output. Hence MPEG DECODER ;)

ninjaedit: which can be either hardware based or softwre based. hardware based is what is needed.

For all of you having problems. Was it in progressive mode? If so what mode? 720p or 1080i?
 
steviep said:
During "CGI" scenes suggests that it's choppy during high-bitrate scenery, so maybe its playback is software-based instead of hardware-based.
Click to expand...

KingPariah777 said:
What the hell does CGI on a movie have to do with decoding?

Its all video to the player...
Click to expand...

We're not talking reel-to-reel projectors pariah, DVD players aren't analog devices they are decoding the movie while you watch it, it's not all just video to the player.
 
figgie said:
:confused:

CGI has nothing to do with decoding.. just the AMOUNT of information that is being displayed does. CGI scene might have more information thereby having a higher bitrate at that point to show the appropiate information.
Click to expand...
Evidence that bitrate changes throughout a DVD? How can a "scene" be a higher bitrate than any other "scene" on the same movie?

figgie said:
DVD do not render. They get decoded from the MPEG serial stream to either digital or analog output. Hence MPEG DECODER ;)
Click to expand...
Thanks for reiterating my point:

KingPariah777 said:
its a DVD, its not rendering anything, computer generated or not.
Click to expand...
 
KingPariah777 said:
Evidence that bitrate changes throughout a DVD? How can a "scene" be a higher bitrate than any other "scene" on the same movie?
Click to expand...


umm yes they do actually. It is not going to be a constant bitrate throughout the movie. Since the entire movie is encoded in mpegx (a compression algorithm) the scene with more movement REQUIRES a higher bit rate than a scene with two people talking and sitting with no movement. ;) The nature of video compression :)
 
KingPariah777 said:
Evidence that bitrate changes throughout a DVD? How can a "scene" be a higher bitrate than any other "scene" on the same movie?
Click to expand...

If your living room DVD player supports it, turn on the bit rate menu. Usually under the main menu of the DVD Player, found on mine by pressing Display. With this on you can see what bit rate the current scene is playing at. Which changes as more or less information appears on screen.

Edit: A Cnet.com article that somewhat explains bit rates.
 
A computer generated scene will have more things moving. A scene where nothing is moving is easier to encode, takes a smaller datastream. On a cgi scene, where there is a a lot of momvement, it's a LOT more to decode in the same amount of time. Hence: a mess.

MPEG encodes by noting which pixels don't change much (or at all) and combining them.
 
http://www.doom9.org/
There's a great site to learn about how DVDs and bitrates work :p

FYI, DVDs are not CBR (constant bitrate), they are VBR (variable bitrate), and the scene being decoded on-screen has everything to do with the bitrate. This is similar to MP3s, in the sense that a CBR 192kbps MP3 will be locked at 192k no matter how much information is being decoded - which is why sometimes CBR MP3s sound "wishy-washy" during certain portions. However, a properly encoded VBR MP3 (which, in your winamp, you see the bitrate constantly switching, anywhere between 32 and 320kbps) will adjust its bitrate to fit as best it can, the amount of audio information being decoded.

I speculated that for some strange reason the X360 may have some kind of primitive software decoding BECAUSE he said it was during a CGI scene. CGI scenes generally have the highest bitrates on DVDs because there is always so much going on, and a lot of movement involved. I've never seen a DVD get choppy during high-bitrate playback unless I tried sticking it into a 300mhz Pentium computer with a videocard that only supports software decoding. Yes, it could be an entirely different reason altogether - but to me, it sounded like a decoding issue. You really should read up on how DVDs work before blasting people in this forum.
 
I tried playing several DVDs earlier today:

- Pitch Black
- Gladiator
- Godzilla :p

All worked fine, no choppy playback or anything. Maybe it's your DVD? I unfortunately don't have the LOTR on DVD so I can't try it out.
 
steviep said:
http://www.doom9.org/
There's a great site to learn about how DVDs and bitrates work :p

FYI, DVDs are not CBR (constant bitrate), they are VBR (variable bitrate), and the scene being decoded on-screen has everything to do with the bitrate. This is similar to MP3s, in the sense that a CBR 192kbps MP3 will be locked at 192k no matter how much information is being decoded - which is why sometimes CBR MP3s sound "wishy-washy" during certain portions. However, a properly encoded VBR MP3 (which, in your winamp, you see the bitrate constantly switching, anywhere between 32 and 320kbps) will adjust its bitrate to fit as best it can, the amount of audio information being decoded.

I speculated that for some strange reason the X360 may have some kind of primitive software decoding BECAUSE he said it was during a CGI scene. CGI scenes generally have the highest bitrates on DVDs because there is always so much going on, and a lot of movement involved. I've never seen a DVD get choppy during high-bitrate playback unless I tried sticking it into a 300mhz Pentium computer with a videocard that only supports software decoding. Yes, it could be an entirely different reason altogether - but to me, it sounded like a decoding issue. You really should read up on how DVDs work before blasting people in this forum.
Click to expand...
My original argument was that CGI is NOT directly related to slowdown during playback...regardless of Bitrate and whatever else.

A CGI scene can be just as slow and simple as a real life scene, and vice versa. CGI has nothing to do with it, you entire position is based on your assumption that CGI scenes are always full of motion and color, which obviously isn't always true.

I wonder if the original poster gets slowdown during the entire movie "Toy Story"? I doubt it...because "CGI" scenes have nothing to do with it, its the action in the movie, not how the scene was created by the filmmakers.

Get it yet, hotshot?

zero002021 said:
I tried playing several DVDs earlier today:

- Pitch Black
- Gladiator
- Godzilla :p

All worked fine, no choppy playback or anything. Maybe it's your DVD? I unfortunately don't have the LOTR on DVD so I can't try it out.
Click to expand...
How did you play Godzilla without TONS of slowdown?!?!?!?! Isn't Godzilla computer generated?

:D :rolleyes:
 
KingPariah777 said:
My original argument was that CGI is NOT directly related to slowdown during playback...regardless of Bitrate and whatever else.

A CGI scene can be just as slow and simple as a real life scene, and vice versa. CGI has nothing to do with it, you entire position is based on your assumption that CGI scenes are always full of motion and color, which obviously isn't always true.

I wonder if the original poster gets slowdown during the entire movie "Toy Story"? I doubt it...because "CGI" scenes have nothing to do with it, its the action in the movie, not how the scene was created by the filmmakers.

Get it yet, hotshot?

How did you play Godzilla without TONS of slowdown?!?!?!?! Isn't Godzilla computer generated?

:D :rolleyes:
Click to expand...

munkle said:
when i play dvd's i notice some nothing major but some slight choppyness during computer generated scenes i dont know why but its only during those scenes and the audio is fine its just the video, i dont know if its the disc because its brand new (lord of the rings extended edition) and never been played before. anyone notice anything like this, its very very slight choppyness?
Click to expand...

Right. So the CGI in any of the LOTR sets is slow and simple. That's why they made it cgi. :p The ~only~ ones that would fit that would be possibly khazad-dum, and even they're pretty busy.

90% of CGI scenes are done because they CANT be done with normal cameras, or it would be hazardous/cost prohibitive. So yes, I'd expect he'd see slowdown in Toy Story, for any scene where a live-action version would use a CGI insert.

With a .9 belief that CGI -> action, especially given Movie == LOTR... you can safely assume that CGI -> Bitrate -> slowdown.
 
lopoetve said:
Right. So the CGI in any of the LOTR sets is slow and simple. That's why they made it cgi. :p The ~only~ ones that would fit that would be possibly khazad-dum, and even they're pretty busy.

90% of CGI scenes are done because they CANT be done with normal cameras, or it would be hazardous/cost prohibitive. So yes, I'd expect he'd see slowdown in Toy Story, for any scene where a live-action version would use a CGI insert.

With a .9 belief that CGI -> action, especially given Movie == LOTR... you can safely assume that CGI -> Bitrate -> slowdown.
Click to expand...

Thank you for that. Some people here need to educate themself about the technology they are trying to act smart about. It could be an isolated issue, in this case. But it DOES sound like a bitrate decoding problem in this case.
 
its not like major choppyness as it seems that some of you have been thinking (maybe thats not what you think?) but its like the screens jumps maybe 2 pixles (i dont know just a referance of how small) once and a while during those scenes, its nothing major at all you barely notice but its there because its smooth and then jumps a tiny very minute distance very very tiny. but oh well, ill try some other dvds if it happens more i just exchange my 360.
 
munkle said:
its not like major choppyness as it seems that some of you have been thinking (maybe thats not what you think?) but its like the screens jumps maybe 2 pixles (i dont know just a referance of how small) once and a while during those scenes, its nothing major at all you barely notice but its there because its smooth and then jumps a tiny very minute distance very very tiny. but oh well, ill try some other dvds if it happens more i just exchange my 360.
Click to expand...
To be honest, yes, I noticed it a little bit ago while watching gladiator. It's very slight and can only affect people who are very prone to notice such things...for example, I am a videophile of sorts, so after a few minutes of watching the movie, without thinking about this thread, I saw it...then remembered the thread.....but my wife takes no notice.....but I get EXACTLY what you are talking about, and you are very correct.
 
Maybe it isn't a software decoding problem then. If you're talking about pixelation/video noise, it might be either a portion of scratched disc, or a DVD-streaming issue, both of which would indicate a crappy DVD drive. My Apex DVD player occasionally does this on burned disc.
 
the easiest place i have noticed to see this happen is when a movie is going to the menu and has an animated scene that goes to the menu, i just played star wars and when the xwing flys into the menu it jumps a little bit everyonce and a while, while its moving, i tested it on a dvd player too, the dvd player is perfectly smooth while the xbox360 jumps a little.

and its not pixleation its like a very slight lag, like the video skips some of the scene to catch up but not very much of the scene to catch up like .01 of a second it skips not much but noticible.

hmm.. if others are not haveing this problem i might call up gamestop and ask if i can exchange it, could this be at all a problem with the hdd? because my box had a big gash over the hdd, and it didnt seem damage but maybe something happened that im not aware of.
 
WTF :confused:

Umm, there is no difference between a CGI scene and a non-CGI scene in a movie. In the end everything on the DVD is encoded into MPEG. Doesn't matter whether the image was produced with a computer or filmed with a camera because the end product is just an image.
 
gwu168 said:
WTF :confused:

Umm, there is no difference between a CGI scene and a non-CGI scene in a movie. In the end everything on the DVD is encoded into MPEG. Doesn't matter whether the image was produced with a computer or filmed with a camera because the end product is just an image.
Click to expand...

*sigh* you people are killing me
The MPEG encoder that creates the compressed movie file analyzes each frame and decides how to encode it. The compression uses some of the same technology as still image compression does to eliminate redundant or irrelevant data. It also uses information from other frames to reduce the overall size of the file. Each frame can be encoded in one of three ways:

As an intraframe - An intraframe contains the complete image data for that frame. This method of encoding provides the least compression.

As a predicted frame - A predicted frame contains just enough information to tell the DVD player how to display the frame based on the most recently displayed intraframe or predicted frame. This means that the frame contains only the data that relates to how the picture has changed from the previous frame.

As a bidirectional frame - In order to display this type of frame, the player must have the information from the surrounding intraframe or predicted frames. Using data from the closest surrounding frames, it uses interpolation (something like averaging) to calculate the position and color of each pixel.

Depending on the type of scene being converted, the encoder will decide which types of frames to use. If a newscast were being converted, a lot more predicted frames could be used, because most of the scene is unaltered from one frame to the next. On the other hand, if a very fast action scene were being converted, in which things changed very quickly from one frame to the next, more intraframes would have to be encoded. The newscast would compress to a much smaller size than the action sequence.

If all of this sounds complicated, then you are starting to get a feeling for how much work your DVD player does to decode an MPEG-2 movie. A lot of processing power is required; even some computers with DVD players can't keep up with the processing required to play a DVD movie.
Click to expand...


http://electronics.howstuffworks.com/dvd4.htm
http://www.howstuffworks.com/dvd.htm

And this is just the absolute BASICS of how video bitrates work in MPEG, essentially, on DVDs.

Munkle, see if exchanging it will do anything, but it may be a while before you get another system. If you're not the only one that has this problem (and you aren't) it may not be an isolated issue. There may be something going on either with the disc-reading (intense heat causes discs not to be read as well), or with the software decoder they may be using, not being able to keep up with all the information being streamed for it. I'm not sure what to tell you.
 
steviep said:
Maybe it isn't a software decoding problem then. If you're talking about pixelation/video noise, it might be either a portion of scratched disc, or a DVD-streaming issue, both of which would indicate a crappy DVD drive. My Apex DVD player occasionally does this on burned disc.
Click to expand...
No it's not noise. For the most part, it's unnoticable, but it's aort of like a frame-skipping kind of thing, where the frame will only skip maybe a pixel or two every once in a while, instead of it being totally fluid.
 
The only issues that come to my mind, then, are either intense heat that debilitates the drive or cpu, or crappy software decoder. But you'd think with the processing power that the X360 has it wouldn't be an issue (so maybe it's the heat?). I could be wrong, but either way, MS should fix this for you.
 
steviep said:
*sigh* you people are killing me



http://electronics.howstuffworks.com/dvd4.htm
http://www.howstuffworks.com/dvd.htm

And this is just the absolute BASICS of how video bitrates work in MPEG, essentially, on DVDs.

Munkle, see if exchanging it will do anything, but it may be a while before you get another system. If you're not the only one that has this problem (and you aren't) it may not be an isolated issue. There may be something going on either with the disc-reading (intense heat causes discs not to be read as well), or with the software decoder they may be using, not being able to keep up with all the information being streamed for it. I'm not sure what to tell you.
Click to expand...

Lol, stop acting uppity. The poster you quoted is correct. CGI has no bearing on what kind of information the decoder is processing. I've seen CGI scenes with high bitrate and CGI scenes with low bitrate. High motion scenes with lots of unique color values will typically have the highest bitrate, but it is not limited to CGI or otherwise. If you are having problems with these DVDs "skipping" it def sounds like a decoding issue. Maybe buffer underrun? BTW, DVD's have an average max bitrate of 9.8MB/s. No matter how much CGI Toy Story 2 has (mentioned earlier in the thread), your decoding subsytem will not process more than that (given DVD).

And yes, MPEG2 doesn't update pixels whose values do not change across frames. The jargon you posted boils down to that.
 
munkle said:
the easiest place i have noticed to see this happen is when a movie is going to the menu and has an animated scene that goes to the menu, i just played star wars and when the xwing flys into the menu it jumps a little bit everyonce and a while, while its moving, i tested it on a dvd player too, the dvd player is perfectly smooth while the xbox360 jumps a little.
Click to expand...

Hooray! A movie I actually have :p

I'll try it out tomorrow and post my results here.
 
pakotlar said:
Lol, stop acting uppity. The poster you quoted is correct. CGI has no bearing on what kind of information the decoder is processing. I've seen CGI scenes with high bitrate and CGI scenes with low bitrate. High motion scenes with lots of unique color values will typically have the highest bitrate, but it is not limited to CGI or otherwise. If you are having problems with these DVDs "skipping" it def sounds like a decoding issue. Maybe buffer underrun? BTW, DVD's have an average max bitrate of 9.8MB/s. No matter how much CGI Toy Story 2 has (mentioned earlier in the thread), your decoding subsytem will not process more than that (given DVD).

And yes, MPEG2 doesn't update pixels whose values do not change across frames. The jargon you posted boils down to that.
Click to expand...

I'm not acting "all uppity" as much as I'm showing my frustration with the lack of understanding on how the way bitrates and decoding works. The poster is NOT right. You are correct in that DVDs have an average max bitrate of 9.8mbps, but every scene in every movie has a different bitrate, and therefore your decoder will have to work harder on some portions of the movie than others. You are also correct in that some CGI scenes can have an extremely low bitrate, but in this case I am correct. The CGI scenes from LOTR (i.e. armies of millions marching, etc) are NOT low bitrate, and will definately top out the decoder and its power. Therefore, in this case, the CGI action scenes have a direct bearing in the amount of information that runs through the decoder. You are absolutely correct in that some "regularly" filmed scenes can have higher or lower bitrates than CGI scenes, but this is all speculative and we are talking about particular scenes in LOTR, in which the X360 is stuttering and such. There is definately an issue with either the DVD-streaming, or the video encoding, or a combination of the two, in this case. If the particular scene tops out the decoder at 9.8mbps and it's skipping a touch, there is an underlying problem with the hardware in one aspect or another.

Thank you for helping to clear up my point, but please be aware that like you - I know what I'm talking about, and that the original poster and those that have posted subsequently with the same issues should contact Microsoft and see what can be done.
 
steviep said:
The only issues that come to my mind, then, are either intense heat that debilitates the drive or cpu, or crappy software decoder. But you'd think with the processing power that the X360 has it wouldn't be an issue (so maybe it's the heat?). I could be wrong, but either way, MS should fix this for you.
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i dont think its heat, as i played cod for 3 hours fine and that should have produced more heat than playing a movie, so im going with a crappy software decoder, i guess if its software i can wait and see if they update the dashboard and maybe that will fix it.
 
I would call them first. It could be that you have a defective unit, and I wouldn't want to be stuck with it. Don't settle for "play now patch later", as that's what consoles are NOT supposed to have.
 
steviep said:
I would call them first. It could be that you have a defective unit, and I wouldn't want to be stuck with it. Don't settle for "play now patch later", as that's what consoles are NOT supposed to have.
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yeah i sent them an email about it explaining that my dvd's play fluidily smooth on a dvd player but in high action seens on the 360 it starts to skip, probably wont get an email back till monday since its thanksgiving.
 
munkle said:
its not like major choppyness as it seems that some of you have been thinking (maybe thats not what you think?) but its like the screens jumps maybe 2 pixles (i dont know just a referance of how small) once and a while during those scenes, its nothing major at all you barely notice but its there because its smooth and then jumps a tiny very minute distance very very tiny. but oh well, ill try some other dvds if it happens more i just exchange my 360.
Click to expand...

I know exactly what you mean... I haven't tried it yet... that sounds exactly like what happens when there is too much data for the decoder to keep up with.
 
lesman said:
To be honest, yes, I noticed it a little bit ago while watching gladiator. It's very slight and can only affect people who are very prone to notice such things...for example, I am a videophile of sorts, so after a few minutes of watching the movie, without thinking about this thread, I saw it...then remembered the thread.....but my wife takes no notice.....but I get EXACTLY what you are talking about, and you are very correct.
Click to expand...

I will fire mine up in a minute and see if I get that as well.
 
pakotlar said:
Lol, stop acting uppity. The poster you quoted is correct. CGI has no bearing on what kind of information the decoder is processing. I've seen CGI scenes with high bitrate and CGI scenes with low bitrate. High motion scenes with lots of unique color values will typically have the highest bitrate, but it is not limited to CGI or otherwise. If you are having problems with these DVDs "skipping" it def sounds like a decoding issue. Maybe buffer underrun? BTW, DVD's have an average max bitrate of 9.8MB/s. No matter how much CGI Toy Story 2 has (mentioned earlier in the thread), your decoding subsytem will not process more than that (given DVD).

And yes, MPEG2 doesn't update pixels whose values do not change across frames. The jargon you posted boils down to that.
Click to expand...

gwu168 said:
WTF :confused:

Umm, there is no difference between a CGI scene and a non-CGI scene in a movie. In the end everything on the DVD is encoded into MPEG. Doesn't matter whether the image was produced with a computer or filmed with a camera because the end product is just an image.
Click to expand...




lopoetve said:
Right. So the CGI in any of the LOTR sets is slow and simple. That's why they made it cgi. :p The ~only~ ones that would fit that would be possibly khazad-dum, and even they're pretty busy.

90% of CGI scenes are done because they CANT be done with normal cameras, or it would be hazardous/cost prohibitive. So yes, I'd expect he'd see slowdown in Toy Story, for any scene where a live-action version would use a CGI insert.

With a .9 belief that CGI -> action, especially given Movie == LOTR... you can safely assume that CGI -> Bitrate -> slowdown.
Click to expand...

I'll go over it again. :)

CGI -> high action, 90% of the time (.9 belief, if you know probability terms).
LOTR CGI -> high action 95% of the time (.95 belief).
High action -> High Bitrate.
Slowdown -> LOTR CGI.
Slowdown -> CGI

Thus with a high level of belief, we can make the connection slowdown -> high bitrate, and thus infer that there is possibly a DVD decoder issue with the Xbox360.
 
i noticed the chopiness immediately when playing Shawshank Redemption.
 
Perhaps this isn't as isolated an issue as I thought... thanks for backing up my point, LE.
 
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