# How does a DVD/CD player work?

**URL:** <https://boards.straightdope.com/t/how-does-a-dvd-cd-player-work/230114>\
**Category:** Factual Questions\
**Created:** [February 20, 2004, 12:54am UTC](https://boards.straightdope.com/t/how-does-a-dvd-cd-player-work/230114 "2004-02-20T00:54:26Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\
**Post date:** [February 20, 2004, 12:54am UTC](https://boards.straightdope.com/t/how-does-a-dvd-cd-player-work/230114/1 "2004-02-20T00:54:26Z")

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Other than “pretty good”, that is. 😉  
Anyway, is the digital info loaded into a memory chip on the player, or does it play right off the disk? It doesn’t _sound_ like the disk is spinning all the time, but I guess it could be. Sometimes I see a tiny ‘blip’ partway through a movie, but it seems much too short for anything to reload from the disk.  
Is it different for CD music and DVD movies? My DVD player does both.  
BTW; Netflix, IMO rocks. 🙂  
Peace,  
mangeorge

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**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\
**Post date:** [February 20, 2004, 1:05am UTC](https://boards.straightdope.com/t/how-does-a-dvd-cd-player-work/230114/2 "2004-02-20T01:05:13Z")

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A regular component (i.e. not portable Walkman-style) CD player and all DVD players constantly read from the spinning disc. Handheld CD players which play MP3s burned onto a CD will usually load the whole file into memory and stop spinning to save battery life.

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**Author:** ![Max\_Torque](https://avatars.discourse-cdn.com/v4/letter/m/e9bcb4/32.png) [@Max\_Torque](https://boards.straightdope.com/u/Max_Torque)\
**Post date:** [February 20, 2004, 1:49am UTC](https://boards.straightdope.com/t/how-does-a-dvd-cd-player-work/230114/3 "2004-02-20T01:49:08Z")

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> [@mangeorge](#):
>
> Sometimes I see a tiny ‘blip’ partway through a movie, but it seems much too short for anything to reload from the disk.

That tiny “blip” is most likely the layer switch. DVDs can have two data layers on one side (although not all of them do). The tiny pause and restart occurs when the laser refocuses to read from the second layer. Many modern DVD players read ahead to prevent the pause, but not all do. Computer DVD playing software, in my experience, always reads ahead, and is always blip-free.

If you want to verify this, check the reviews at [The Digital Bits](http://www.thedigitalbits.com), find one for a movie that’s in your collection, and note from the heading of the review where the layer switch takes place (for example, the switch in **Frailty** takes place at 1:11:35 in chapter 18), and check that point in your movie.