Compression of the video&audio stream + Web Interface (1 Viewer)

[squiddy]

Hello,

what do you think about adding compression into the new TV-Engine. I use it at home with my wireless network and some times it hangs, because of the low bandwidth I have due to my bad signal. If the server would be able to transmit compressed streams, these problems could be solved. Especially for wireless HTPCs this option would be interesting. With enough bandwidth, you could also be able to stream your TV over Internet. The upstream of ADSL is not very good, but if you would use a fast connection home with much upstream, you would not need to have a great connection for downloading the stream. Though it would be possible to watch it from nearly everywhere. But this would not be necessary, but a minor compression is in my opinion very useful.

Additionally, a Web-Interface for the masterserver could be interesting. Managing your recordings from anywhere, without having mediaportal installed.

So please tell me, what you think of these ideas


Squiddy

 

[Maschine]

Hi,

I think real time compression needs too much CPU power and is therefor hard to realize... That's also a reason for the bad performance of SW cards. They need to compress the TV signal with a software encoder which uses a lot system resources.

A webinterface is definately planned. See the forums for a thread "New webinterface".

Maschine

 

[squiddy]

What I'm thinking of is not a DivX compression or so, but a compression like for example taking half the width & height from the source video. Several HDTV screens from TVs have a higher resolution and they simply double the signal, so it would also work vice versa. Or some kind of very weak compression, not taking too much CPU power but taking the bandwidth down.

 

[Maschine]

If you resize the picture you still need to recompress the video stream. Which leads us back to the performance problems told above.

TVs don't modify the source material. They just scale it for viewing. So we still had to send all data over the network and could then just resize on the client. But that doesn't save any bandwidth at all.

If you know a good "weak compression" I'd be glad if you could point me to some links.

Maschine

 

[roosterx]

Maschine: isn't this one of the features i req some days ago, only i called it transcode - something that works perfectly well with SageTv.

 

[HappyTalk]

Yer MythTV does exactly this via a web interface exactly as you described. It uses VLC (if i remember correctly) and can be easily invoked via a command line. You can then watch it remotely using media player or vlc. You could stream the original mpeg2 or a version transcoded on the fly using xvid/wmv/other codec. You could also stream your other recordings or videos in a similar manner.

This was under unix and was not problem free but did work. VLC is open source and available for windows. The first thing though I guess would be to code a web service plugin exposing MP's main functionality, then you could quickly create a web app and/or regular app to communicate. It would be interesting to see how well (or badly) a
mp_client-->mp_web_server-->mp-tv_server implementation of this kind would work for remotely automating mediaportal.

 

[dodo]

Technically you could use VLC now to stream. Not tried it myself yet with Mediaportal but you would do this:
- Set VLC to receive the MP stream on the local computer.
- Set VLC to transcode and stream the transcoded video
- Use VLC on another computer to receive the transcoded video.
I have done this before using just TSReader to transcode DVB-T and there were no CPU issues at all.

 

[Maschine]

Hi dodo,

thanks for that nice post. I didn't even know that VLC could transcode video

Now I know where to search and will definately look at that.

Maschine

 

[quake74]

Not to mention the obvious, but a very good example to follow (and expand upon) is the http://gbpvr.com/pmwiki/pmwiki.php/Utility/EnhancedWebAdmin plugin for GBPVR. BTW, it looks to me like it's written in C#, so understanding it and copying its behaviour shouldn't be too difficult.

 

[dodo]

OK, I've just checked it out and VLC will quite happily transcode to mp4 and UDP broadcast to another PC on my wireless network. It can even reduce the size of the video.

Tomorrow I'll be trying sending the video over the net to work so I can watch the Ashes.

Keep your fingers crossed for me that the TV engine doesn't crash...

Here's a quick guide:
1. See here to start up TV server: http://wiki.team-mediaportal.com/TV-Engine_0.3/troubleshooting-streamtest

2. On the Open Network Stream dialog in VLC, select "Stream/Save" in Advanced options, then click on Settings.

3. Select "UDP" and the destination IP address.
4. Select your transcoding options (I used MP4V for video and MP3 for audio). Use "Scale" to change the video size.
5. On the destination computer, start up VLC, Open Network Stream and select UDP. Click on OK and you should see the video and audio.