Please explain why when watching a film on dvd it looks fine, the picture is not going to fast or to slow so what is the difference with blu-ray at 24fps the picture still looks the same as far as movement goes, not to fast not to slow, so what is this 24fps all about. I know films are filmed at 24fps but I cannot see any movement difference between dvd and 24fps blu-ray.
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24 FPS Please explain
- Thread starter kitkat
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The_Lhc
Well-known member
kitkat:Please explain why when watching a film on dvd it looks fine, the picture is not going to fast or to slow
That isn't strictly true, I used to buy a lot of Stargate SG-1 DVDs, region 2 and never thought there was anything wrong with them, I then happened to download a rip of an episode to watch on my PC, the difference in tone in the actors voices between the DVD and the download was remarkable, the region 2 DVD all the voices were noticably higher in pitch because of the effect of the framerate being speeded up to squeeze it into our refresh rate. It made it really hard for me to watch the DVDs after that, as everybody sounded like they'd been sucking on helium.
That isn't strictly true, I used to buy a lot of Stargate SG-1 DVDs, region 2 and never thought there was anything wrong with them, I then happened to download a rip of an episode to watch on my PC, the difference in tone in the actors voices between the DVD and the download was remarkable, the region 2 DVD all the voices were noticably higher in pitch because of the effect of the framerate being speeded up to squeeze it into our refresh rate. It made it really hard for me to watch the DVDs after that, as everybody sounded like they'd been sucking on helium.
Paul.
Well-known member
As long as everything in the chain of devices supports the frame rate, everything should come out sounding the same. I guess your TV didn't like the 60hz feed.
My TV wont support true 24p, although the PS3 does. this means i get a little jaggyness with slow panning shots in films from the conversion.
My TV wont support true 24p, although the PS3 does. this means i get a little jaggyness with slow panning shots in films from the conversion.
Thats not strictly true Paul, when a film that has been shoot in 24fps is played back on a display that does not support it, and it is sped upto 60HZ the sound track runs approxiamtely 3% ( think it's 6% actually, can't find the document at the moment) faster than it is recorded at. Therefore The vocals will seem more high pitched, its only a subtle difference, but once you play a sound track in both modes you should be able to tell the difference, I certainly can.
The_Lhc
Well-known member
What he said, I'd never have noticed if I hadn't watched a downloaded copy. The DVDs were being watched on an old Sony Trinitron CRT incidentally, none of your modern stuff.
Paul.
Well-known member
markjaspi:Thats not strictly true Paul, when a film that has been shoot in 24fps is played back on a display that does not support it, and it is sped upto 60HZ the sound track runs approxiamtely 3% faster than it is recorded at. Therefore The vocals will seem more high pitched, its only a subtle difference, but once you play a sound track in both modes you should be able to tell the difference, I certainly can.
My TV uses 3:2 pulldown to add frames rather than speed it up. Dialogue remains at the correct speed, but this is where the slight juddering comes from in slow panning shots.
My TV uses 3:2 pulldown to add frames rather than speed it up. Dialogue remains at the correct speed, but this is where the slight juddering comes from in slow panning shots.
The_Lhc
Well-known member
Paul Hobbs:
markjaspi:Thats not strictly true Paul, when a film that has been shoot in 24fps is played back on a display that does not support it, and it is sped upto 60HZ the sound track runs approxiamtely 3% faster than it is recorded at. Therefore The vocals will seem more high pitched, its only a subtle difference, but once you play a sound track in both modes you should be able to tell the difference, I certainly can.
My TV uses 3:2 pulldown to add frames rather than speed it up. Dialogue remains at the correct speed, but this is where the slight juddering comes from in slow panning shots.
Your current TV might, the TV you had ten years ago wouldn't have done.
markjaspi:Thats not strictly true Paul, when a film that has been shoot in 24fps is played back on a display that does not support it, and it is sped upto 60HZ the sound track runs approxiamtely 3% faster than it is recorded at. Therefore The vocals will seem more high pitched, its only a subtle difference, but once you play a sound track in both modes you should be able to tell the difference, I certainly can.
My TV uses 3:2 pulldown to add frames rather than speed it up. Dialogue remains at the correct speed, but this is where the slight juddering comes from in slow panning shots.
Your current TV might, the TV you had ten years ago wouldn't have done.
Does not matter, the sound track still needs to be altered at some point to match the picture otherwise the sync will be off. Remember this only for 24fps native shoot and recorded content.
Paul.
Well-known member
the_lhc:
Your current TV might, the TV you had ten years ago wouldn't have done.
The question referenced Bluray which didn't exist 10 years ago, so a moot point. Also, I did not own a TV 10 years ago!
markjaspi:Does not matter, the sound track still needs to be altered at some point to match the picture otherwise the sync will be off. Remember this only for 24fps native shoot and recorded content.
3:2 does not affect the audio channel at all as it duplicates frames (3 of one frame, 2 of the next) to pad out the video section to match the audio.
The audio speed up problem only occurs on PAL (50fps) TV's that cannot manage NTSC (60fps) frequencies. 24 fps will sync up with 60fps quite nicely. 24/2 = 12. (12*3)+(12*2)=60fps.
Your current TV might, the TV you had ten years ago wouldn't have done.
The question referenced Bluray which didn't exist 10 years ago, so a moot point. Also, I did not own a TV 10 years ago!
markjaspi:Does not matter, the sound track still needs to be altered at some point to match the picture otherwise the sync will be off. Remember this only for 24fps native shoot and recorded content.
3:2 does not affect the audio channel at all as it duplicates frames (3 of one frame, 2 of the next) to pad out the video section to match the audio.
The audio speed up problem only occurs on PAL (50fps) TV's that cannot manage NTSC (60fps) frequencies. 24 fps will sync up with 60fps quite nicely. 24/2 = 12. (12*3)+(12*2)=60fps.
The_Lhc
Well-known member
Paul Hobbs:
the_lhc:
Your current TV might, the TV you had ten years ago wouldn't have done.
The question referenced Bluray which didn't exist 10 years ago, so a moot point.
DVD was also referenced, specifically wrt PAL speed up, which I've experienced, hence it not being a moot point.
the_lhc:
Your current TV might, the TV you had ten years ago wouldn't have done.
The question referenced Bluray which didn't exist 10 years ago, so a moot point.
DVD was also referenced, specifically wrt PAL speed up, which I've experienced, hence it not being a moot point.
Paul.
Well-known member
If still not 100% sure what the original question was!
As far as I can tell, it may be 'what is the point of 24fps?' I saw no reference to fast audio or PAL, the OP seemed happy with his systems timing.
As far as I can tell, it may be 'what is the point of 24fps?' I saw no reference to fast audio or PAL, the OP seemed happy with his systems timing.
Since changing my TV for one that supports 24 fp, I have noticed that the audio on Blurays is clearer. It cannot be the TV because the audio is fed directly by analogue from the player to the amp. Therefore the only conclusion is that the audio is now at the correct speed, instead of speeded up by a few%.
As you say there's nothing too wrong with 25fps, and you wouldn't normally notice any big problem with the film. It takes the original 24 fps and speeds it up every so slightly, showing 25fps. The vide is slightly quicker, so the film doesn't run as long, and sound slightly higher as the speed up increases the frequency.
24 fps you get the picture and sound as they were recorded.
I agree that 60 fps with 3:2 pulldown would not cause any speed-up. It just shows one of the 24 frames twice, the next 3 times, refreshing the screen 60 times per second, but only showing 24 frames. some of the frames are shown slightly longer than others which can cause the judder mentioned.
24 fps you get the picture and sound as they were recorded.
I agree that 60 fps with 3:2 pulldown would not cause any speed-up. It just shows one of the 24 frames twice, the next 3 times, refreshing the screen 60 times per second, but only showing 24 frames. some of the frames are shown slightly longer than others which can cause the judder mentioned.
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