Accessible tv tuners from the cli?
hittsjunk at gmail.com
Thu Oct 27 02:09:19 EDT 2011
Hi. You forgot that local tv is still one of the best sources for local news.
The web probably will never replace that. When I realized tvs were going digital,
I bought a tv tuner just so I could have access to my local tv stations. It's cool not to need
sighted help to manage my tv.
During our April disaster, local tv was the best source for weather info.
The weather radio didn't have backup, so it failed with the power.
True, you had to listen to tv audio on a battery radio when the
power grid failed, but the tv broadcast saved a lot of lives.
I agree the source for entertainment will move to the web, but there will be a place for
local broadcasting into the future.
On Thu, Oct 27, 2011 at 01:06:01AM -0400, Janina Sajka wrote:
> Thanks, Bob, for all this good info. I'm not looking to do this myself
> just now for a number of reasons, but I'm keeping your post against the
> day I do want to do this.
> Question: Isn't it worth considering simply accessing the content you
> want over the net using a browser? Perhaps with a service like hulu.com
> which is supposedly quite accessible. The famous name in this space, of
> course, it Net Flix, but they're supposedly not so accessible.
> I'd love to hear a discussion of the pros and cons of such services. I
> am personally of the opinion that the future of broadcasting is the web,
> not in the least because it's fully international and intrinsically
> time-shift capable.
> pigiron at gmx.com writes:
> > On Wed, 26 Oct 2011 17:19:59 -0600 "Littlefield, Tyler" <tyler at tysdomain.com>
> > wrote:
> > > Hello all:
> > > I was curious if any of you have tried using a TV tuner from the cli?
> > > How accessible or otherwise was it? I'm building a computer hopefully
> > > soon, and would like to throw in a tuner, but I don't know how it'd work
> > > with speakup or if there's an accessible program to interface with them.
> > >
> > While I'm sighted, I run everything for my TV tuner from the command line
> > except for post editing any recorded shows. But there's even some simple CLI
> > video editors. I've never used them, so I can't speak to those.
> > Getting everything set up correctly is definitely a head scratcher though. So
> > set aside gobs of time and get your zen in shape in order to keep your blood
> > pressure in check.
> > It all starts with getting a TV tuner that Linux likes. I strongly suggest that
> > you buy one that the Video4Linux, otherwise known as "V4L", Linux kernel
> > subsystem supports. A good place to start is this web site:
> > http://www.linuxtv.org/wiki/index.php/Hardware_Device_Information
> > Like most Linux documentation, it's only slightly out of date; chuckle.
> > While you may find drivers and applications for non-V4L supported tuners on the
> > internet, you'll probably find that they are old, or not maintained, or both.
> > All the current action is on the V4L code, and it's been that way for awhile
> > now.
> > You did not say which country you live in, nor which types of signals you'll be
> > trying to watch or capture. That will make big a difference for some of the
> > following information, along with which TV tuner you buy.
> > One of the first puzzlers you'll encounter is all the strange new buzz words.
> > One is the anagram "DVB". I means Digital Video Broadcast, which differentiates
> > it from the old analog broadcasts and tuners. Then you'll hit things like the
> > words "DVB-C", "DVB-S", and "DVB-T". It took me awhile to figure out that the
> > letter "C" means cable. The letter "S" means satellite. And the letter "T" means
> > terrestrial; which is the over the air signal. You'll sometimes see that
> > shortened to the anagram "OTA". Confused yet?
> > After you've slogged through all that, and figured out which tuner to buy, you
> > install it and verify that Linux likes it by checking the output of the dmesg
> > command. You should also now have files and directories located under
> > the /dev/dvb directory.
> > If you get this far, you next need to create what's called a "channels" file.
> > This is simply a strangely formatted text file that contains all the TV channels
> > that the tuner finds in your local area. It's analogous to scanning the
> > available channels on one of those new fangled digital televisions.
> > There are multiple command line programs that will create the "channels" file.
> > Which one you use partially depends on what type of signal you want to capture;
> > such as cable, satellite, or terrestrial; along with which country you live in.
> > Drill down from this web page for more info:
> > http://www.linuxtv.org/wiki/index.php/Frequency_scan
> > After you've successfully scanned the TV channels for your area and created the
> > "channels" file, you'll find that you probably need copy that sucker into
> > multiple directories. The mplayer program expects to find it in one place,
> > while the xine player expects it in another, and so on. But once you get in
> > place, you can now tell the player which TV channel to play by using it's name.
> > For example, if you want to play a station called "WCBS" using the mplayer
> > application you could enter the following:
> > mplayer tv://WCBS
> > But, how do you know what station name to use??? The answer is to look inside
> > that strangely formatted "channels" text file you created. Each line is a
> > different channel, and the first field is the TV station name. Each field
> > within a line is separated by the colon character. It's safe to edit the
> > channel file and change those TV station names to something you like. But, do
> > not change any other field on a line.
> > Note that mplayer normally spews a ton of output to the terminal, you may
> > want to try the "-really-quiet" parameter to keep the output from speakup to
> > a minimum, or turn it off.
> > If you wish to capture a show, just one simple way to do it from the command
> > line is to bring up a terminal and use one of the "zap" programs provided in
> > the "dvb-apps" package to tune your tuner to the particular TV channel. Which
> > "zap" program you use depends on the type of TV signal. See the following for
> > more info:
> > http://www.linuxtv.org/wiki/index.php/Zap
> > Next, open another terminal and simply redirect the output of your tuner device
> > to a file. For example, something like the following might work if you only
> > have one TV tuner installed:
> > cat /dev/dvb/adapter0/dvr0 > testvideo.mpg
> > While that documentation states that the "zap" programs can also be used to
> > record a program, the "azap" program that I use doesn't support it.
> > If you attempt to capture the new ATSC over the air digital HDTV channels now
> > found in the USA, expect to eat up gigabytes of drive space. You'll find that
> > the sucker is in the MPEG Transport Stream format, and unless you live next
> > door to the transmitter, it will also contain errors. While mplayer and VLC
> > among others, will play the file, if you want to convert it into a DVD format,
> > you'll need to fix all those errors. I'll leave those numerous painful hints
> > for some other time.
> > I found a really obscure command line program from a bloke in Australia that
> > will set up a timed recording, but I had to modify the hell out his C language
> > program. For one thing, he has the channels hard coded; ouch! But here's a link
> > if you're looking for even further frustrations:
> > http://www.togaware.com/linux/survivor/TV_Recording.html
> > You simply tell it which channel to record, the output file name, what time to
> > start recording, and when to stop. Kind of like a DVR.
> > I could go on forever, but I've bored you enough. Hope this helps, and good
> > luck.
> > peace,
> > bob
> > _______________________________________________
> > Speakup mailing list
> > Speakup at braille.uwo.ca
> > http://speech.braille.uwo.ca/mailman/listinfo/speakup
> Janina Sajka, Phone: +1.443.300.2200
> sip:janina at asterisk.rednote.net
> Chair, Open Accessibility janina at a11y.org
> Linux Foundation http://a11y.org
> Chair, Protocols & Formats
> Web Accessibility Initiative http://www.w3.org/wai/pf
> World Wide Web Consortium (W3C)
> Speakup mailing list
> Speakup at braille.uwo.ca
More information about the Speakup