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Problem with audio on DVD


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Old 03-08-2016, 22:06
Conor_McGlone
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I've noticed a problem when playin DVDs whether it be on my PC, Blu-Ray, or portable DVD player: the pitch on the audio track is higher than it should be by a semitone. I have compared the sound on the DVDs with their respective soundtracks (which are at the at the correct pitch) and clips online, and have noticed a significant difference which is quite frustrating for me. does anyone know what the problem is and how to fix it for the different players?
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Old 03-08-2016, 22:22
chrisjr
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If it is a film then it is probably a consequence of the film frame rate of 24 frames per second being speeded up to match the UK video frame rate of 25 frames per second. And of course the audio is speeded up by the same amount to maintain synch with the video.

Nowt you can do about it unfortunately.
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Old 03-08-2016, 22:28
Conor_McGlone
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If it is a film then it is probably a consequence of the film frame rate of 24 frames per second being speeded up to match the UK video frame rate of 25 frames per second. And of course the audio is speeded up by the same amount to maintain synch with the video.

Nowt you can do about it unfortunately.
So does that mean that all films/DVDs in the UK are at a higher pitch than the originals/US versions?

Is this the same for digital downloads like itunes and also for blu-ray discs?
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Old 03-08-2016, 23:08
chrisjr
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So does that mean that all films/DVDs in the UK are at a higher pitch than the originals/US versions?

Is this the same for digital downloads like itunes and also for blu-ray discs?
The problem is that the video formats used by TVs generally follow the broadcast specification which in the US is 29.97 frames per second (yes it is an odd number to use but there are good reasons for that) and in the UK 25 frames per second.

In the US the film frame rate is able to be converted to the video frame rate using a technique that effectively generates extra frames. It does actually slow down the film by a very small amount.

In the UK the film frame rate is close to the video frame rate so they probably decided that speeding up the film by about 4% was easier than trying to convert the frame rate.

This explains it better if you are interested.

http://www.paradiso-design.net/videostandards_en.html

Blu-Rays may actually play at the "correct" 24 frames per second and your TV may well be able to display that frame rate properly. I have tried it on my LG TV and a Blu-Ray shows a 24 fps rate and a DVD 25 fps.

Digital downloads could be anything depending on the source.
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Old 03-08-2016, 23:23
Chris Frost
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So does that mean that all films/DVDs in the UK are at a higher pitch than the originals/US versions?
That very much depends on several things. In simple terms if the original movie was shot at 24 frames per second and then converted to 25fps for the PAL version without audio pitch correction then yes. If it's a US TV program or was shot on video in the US then the frame rate 30fps. When that's converted to 25fps for PAL they drop frames but the audio pitch doesn't change.

Feature films shot at 24fps can be transferred to DVD at 25fps with a pitch correction to compensate for the 4% faster running time.

Is this the same for digital downloads like itunes and also for blu-ray discs?
Not necessarily.

Blu-rays are encoded to run at 24fps. Depending on the settings of your BD player then you can either output at 1080p/24 or have the player convert in to an interlaced signal 1080i/60. Either way the audio stays the correct pitch. Both formats along with 1080i/50 are included in the HDTV signal spec.

iTunes - well it depends if you're watching a movie in it's original theatrical release at 24fps or whether it has been messed with.
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