I know the reason that my TiVo doesn’t allow me to simultaneously record one show and watch another is because it has one tuner. I’ve had TVs that include Picture-in-Picture, but only one tuner, so you had to use a VCR to really use the P-i-P feature. My current TV has 2 tuners and P-i-P, which is great.
Seeing as this “tuner” gadget seems to be the only thing standing between me and, say, a TiVo that can record 5 different shows at once by including 5 tuners, why doesn’t anyone do this? What’s the problem? Are they expensive, or is there a worldwide tuner shortage, or do the cable companies get pissy if you watch more than one channel at a time?
I’m not particularly wondering about TiVo - I just used it as an example.
I’m more just wondering why they don’t make TiVos/DVD recorders/VCRs/TVs with a bunch of tuners in them; it seems to me that people would like the ability to record multiple channels at once, but I’ve seen at most 2 tuners in one box.
Would simultaneous recording of multiple video and audio streams work with one processor and one hard drive? I’m wondering how it would be possible to capture more than one program at a time without multiple drives. An hour TV show in normal TV resolution takes up a lot of space! If a DVR drive was partitioned, would it be able to write to both partitions at the same time without dropped data?
I assume the reason that some devices do/did not have two built-in tuners is just to keep costs down. Usually consumer electronics have a very thin margin.
Right, this is why a Tivo or other devices don’t have five tuners. While you could use one to watch, you wouldn’t be able to simultaneously record with the other four. At least not without duplicating some of the other hardware. Tivo used to brag about all the optimizations that they did to the hard-drive controller just to get it fast enough to keep up with a simultaneous record and play. While you could get higher-end hardware and add more memory buffers, you run in to the thin profit margins again.
I have the previously mentioned DirectTV Tivo box… I routinely record two shows simultaneously. Even watching a third previously recorded show whilst the other two are recording. This is why Tivo is better than world peace
I don’t think partitioning would help/hurt–it’s all just hunks of data (like simultaneously downloading two files via FTP; you don’t need two partitions, just sufficient bandwidth/etc. to make the copy time reasonable). I think it just depends on your processor speed, bus speed, and drive write speed. Recording video to hard drives is nothing new (it’s only putting it in the consumer market that is); I’m sure we must have people here with extensive AVID/RAID experience who could tell you how fast you can record video to HD, and if you could do multiple streams.
[QUOTE=AthenaI’m more just wondering why they don’t make TiVos/DVD recorders/VCRs/TVs with a bunch of tuners in them; it seems to me that people would like the ability to record multiple channels at once, but I’ve seen at most 2 tuners in one box.[/QUOTE]
My DVR can record two channels while you watch a third live channel*, even though it only has two tuners, because it records digital TV, where several TV channels are “multiplexed” into one signal. There are six multiplexes here, so if the recorder had a fast enough processor and disk it would only need six tuners to record every channel simultaneousy, which would be about 40 channels.
if the third channel is on the same multiplex as one of the other two
You CAN watch one show while recording another. If you put the TiVo in standby mode…it will “release” your television from TiVo control (while the TiVo is still recording its scheduled program). You can then use the regular tv tuner to watch any show (of course you won’t have any TiVo capabilities, like pausing the show, for what you’re watching)
{/nitpik}
I agree. We love our DirecTV TiVo box. What I don’t understand is why the two tuners need two cables. These cables go all the way back to the multiswitch at the bottom of the satellite dish. Why can’t I run one cable from the multiswitch and then split it behind the TV (or why can’t the TiVo split the signal itself)?
I know the answer to that one! It’s because of the signal strength of the multiswitch at the Dish. Newer DISHNetwork dishes use more signal out of the sattlelite so that you can, in effect, put a splitter near the tuner box.
My Time Warner DVR has two tuners and does HD too; it comes with a 166mHz Sparc processor and 64MB of RAM, so I’m guessing processing power isn’t much of an issue, especially when you’re talking about dedicated hardware and software.
And for only $4,700, you can buy the Sony Vaio Type X DVR that has six tuners
Sorry to be the Sourpuss in all this, but Jeez Louise, people!
How many shows can possibly be on at the same time that you want to watch?
Five freaking tuners? Are there ever actually Five (5!) shows on at the SAME time that will never be on again that you HAVE to watch?!?
Even with a one-tuner Tivo hooked up to DirecTV I’m able to catch everything I want thanks to reruns in the middle of the night.
But two tuners I respect. Watch now + record now = power.
But with great power comes great responsibility. With more than two tuners you have the potential to become PURE EVIL.
Be wary of your great power, and wield it sparingly. For when you become comfortable with this power you will accept nothing less than it, and worlds will crumble before you.
all the time… well not 5 tuners, but 3 would be nice. It never fails that I want to watch something on the Hitler channel or somesuch ed-U-K-shunal channel and there is some sitcom or other on at the same time (or 1/2 hour in)… not to mention all the time games netowrks play… a minute here and there really screws up stuff.
It happens for us every Sunday at 9pm (Desperate Housewives, Rome, and Fox’s animated lineup) and every Wednesday at 9pm (Lost, Veronica Mars, Trading Spouses). Keep in mind that with a DVR you actually watch the shows whenever - we currently have three weeks of Rome to catch up on. It’s not like the missus and I watch 29 different shows, it’s just that Sundays and Wednesdays are bad for us.
it’s very expensive. A DVR tuner that tunes both analog and digital TV (or even just analog) typically needs a complicated tunig apparatus thingy (it’s a high quality programmable band pass filter), a high quality ADC and a DSP to process the signal. Then you need enough memory and bus bandwidth and if your DVR compresses the stream, a video compression chip per tuner. You need your hard drive to be able to handle this many simultaneous writes, and the CPU not to choke on that many threads.
Yeah, but that’s because your DVR just has to record the digital stream to the disk. TiVos and other DVRs that are able to deal with non-digital cable and over the air signals have to have MPEG2 encoding hardware to do the A-to-D conversion on the fly. It’s this hardware that’s expensive, not the actual RF tuner.
Also, it may be that going to 2 tuners is easy (with the appropriate encoders), but that going much higher than that becomes unfeasible without spending a lot on specialized hardware or R&D. At 4 or 5 video streams, you’re getting a few Megabytes a second that have to be dealt with. Now, a standard hard drive should be able to deal with a few MB/sec at sustained writes without any problem, but with 4 different data streams, you can’t just make one sustained write. Which calls for some snazzy memory caching going on, which requires additional memory. And whatever you do, you have to make sure that it continues to work under the worst circumstances (ie, maximum data coming in), even when the user is doing all kinds of crazy clicking on the interface and loading up a different old show every few seconds. If the interface lags because it has to wait for the disk to write or, even worse, the recording gets messed up because the interface got priority, you have a very unhappy customer.
It may just be easier and simpler to make a device with one or two tuners and let the really hardcore people buy two of them.
