# DVR recording question **URL:** \ **Category:** Factual Questions\ **Created:** [April 19, 2020, 2:58pm UTC](https://boards.straightdope.com/t/dvr-recording-question/852126 "2020-04-19T14:58:23Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Bijou\_Drains](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bijou_drains/32/2814_2.png) [@Bijou\_Drains](https://boards.straightdope.com/u/Bijou_Drains)\ **Post date:** [April 19, 2020, 2:58pm UTC](https://boards.straightdope.com/t/dvr-recording-question/852126/1 "2020-04-19T14:58:23Z")
Watching the at home concert last night and I hit the record button when there was 40 mins left. But it recorded the last 60 minutes, not 40. I assume this is by design. Does this mean it is already recording as long as I don’t change the channel? ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [April 19, 2020, 3:14pm UTC](https://boards.straightdope.com/t/dvr-recording-question/852126/2 "2020-04-19T15:14:17Z")
Most DVR software keeps a running buffer of the last N minutes, so that you can instant-replay or seek back a short distance. When you start recording, since it already has the recent N minutes recorded, it just starts the recording with that buffer. At least, so I presume based on your description. Not all DVR software will do that. ---
**Author:** ![Bijou\_Drains](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bijou_drains/32/2814_2.png) [@Bijou\_Drains](https://boards.straightdope.com/u/Bijou_Drains)\ **Post date:** [April 19, 2020, 3:18pm UTC](https://boards.straightdope.com/t/dvr-recording-question/852126/3 "2020-04-19T15:18:32Z")
I think I remember this happened in the past too. Maybe the buffer is 20 minutes since that is the extra amount I got. this is ATT Uverse if anyone is curious. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [April 19, 2020, 5:00pm UTC](https://boards.straightdope.com/t/dvr-recording-question/852126/4 "2020-04-19T17:00:13Z")
> [@Bijou\_Drains](#): > > I think I remember this happened in the past too. Maybe the buffer is 20 minutes since that is the extra amount I got. this is ATT Uverse if anyone is curious. Pretty easy to test. Just keep your TV on a channel for an hour and then hit the rewind button and see how far back it goes. That’s your buffer. ---
**Author:** ![keno](https://avatars.discourse-cdn.com/v4/letter/k/f9ae1b/32.png) [@keno](https://boards.straightdope.com/u/keno)\ **Post date:** [April 19, 2020, 5:29pm UTC](https://boards.straightdope.com/t/dvr-recording-question/852126/5 "2020-04-19T17:29:50Z")
Using Verizon FIOS it records the last two channels – that’s how you can pause and rewind ‘live’ broadcasts. You can measure the size of the buffer by pausing a live feed. It’ll jump back to ‘live’ signal when the buffer is full. ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [April 19, 2020, 7:22pm UTC](https://boards.straightdope.com/t/dvr-recording-question/852126/6 "2020-04-19T19:22:16Z")
My DVR has a buffer of 90 minutes. If the DVR has been on for a while on the Law and Order all the time channel, and I turn on the screen at the last minute of an episode, I can either rewind to the beginning of the episode (or really, the end of the previous episode) - or hit record and get the whole episode recorded to watch later (what I can’t do is record the last half hour of the earlier episode).