DVB-T Radio Support

[bgowland]

Out of interest what settings does lame use in the encoding? I am wondering how the sound quality is affected by the conversion. In all the DVB-T ads the sound is described as 'near CD quality', so what impact does encoding to MP3 have?

I've yet to work out how to set LAME for particular bitrates etc. Looking at the gbnetradio mp3 file properties, it seems to default to 128Kbps 48KHz.

The actual broadcast streams for DVB-T radio vary from 96Kbps to 192Kbps - ideally I'd like to be able to control the LAME encoder to match what is being broadcast. It's on the ToDo list. I may also add a live playback mode (i.e., render directly to the audio device) if I can find the time.

Cheers,
Brian

[Graham]

Version 1.3

The problem with the plugin not appearing in Config.exe is fixed.

But channel changes don't work right.

I deleted the old version (1.2) and copied the 1.3 files and started again. The install and start of the service worked well. Starting the first time asked me to do a channel scan and that went well. The db3 has squillions of entries so it seems that the EPG grab is working well.

And the bad news ... Selecting the first channel works okay. Selecting a second and subsequent channel immediately stops the current channel from playing, then nothing happens for about 20 seconds, then the logo changes to the logo of the new channel but there is no sound. Pressing play again (without selecting a new channel) gives me sound from the new channel.

The above is what you see in the attached logs.

I can also change channels okay by pressing Stop, then selecting the new channel.

Thanks for your good work.

Graham

[bgowland]

And the bad news ... Selecting the first channel works okay. Selecting a second and subsequent channel immediately stops the current channel from playing, then nothing happens for about 20 seconds, then the logo changes to the logo of the new channel but there is no sound. Pressing play again (without selecting a new channel) gives me sound from the new channel.

First - glad you've at least got it working of sorts.

I notice your DVBTRadio.xml has <StopOnChannelChange> set to true. Are your logs from when it was set like this? What happens when it is set to 'false'?

I think I can see something in the pvrx2.exe-native.log which doesn't look right but I'm not sure why...

Code:

2008-06-23 15:02:02.667    VERBOSE    Graph contains the following filters:
2008-06-23 15:02:02.667    VERBOSE     - DirectSound: Realtek HD Audio output
2008-06-23 15:02:02.667    VERBOSE     - MPEG Layer-3 Decoder
2008-06-23 15:02:02.667    VERBOSE     - MPEG-I Stream Splitter
2008-06-23 15:02:02.667    VERBOSE     - SOURCE
...
2008-06-23 15:02:39.308    VERBOSE    Graph contains the following filters:
2008-06-23 15:02:39.308    VERBOSE     - MPEG-I Stream Splitter
2008-06-23 15:02:39.308    VERBOSE     - SOURCE
2008-06-23 15:02:39.308    VERBOSE     - DirectSound: Realtek HD Audio output

...the above is PVRX2 building its playback graphs. The first is when you selected play and the second is it building a new playback graph when you submitted a new tuning. The first has an MPEG Layer-3 Decoder in it, but the second doesn't.

If I set my StopOnChannelChange to 'true', PVRX2 builds the new graph consistently each time I change channel on the fly, but mine uses the MPA Decoder filter (not the MPEG Layer-3 Decoder).

You could try the MPA Decoder from here http://www.free-codecs.com/download/MPA_Decoder.htm

Cheers,
Brian

[Graham]

You could try the MPA Decoder from here http://www.free-codecs.com/download/MPA_Decoder.htm

Sorry, didn't make any difference. Edited log ...

2008-06-23 18:18:43.652 VERBOSE getSetting(ListGraphFilters)
2008-06-23 18:18:43.652 VERBOSE Graph contains the following filters:
2008-06-23 18:18:43.652 VERBOSE - DirectSound: Realtek HD Audio output
2008-06-23 18:18:43.652 VERBOSE - MPA Decoder Filter
2008-06-23 18:18:43.652 VERBOSE - MPEG-I Stream Splitter
2008-06-23 18:18:43.652 VERBOSE - SOURCE
2008-06-23 18:18:43.652 VERBOSE getSetting(SaveGraphFiles)
2008-06-23 18:18:46.964 VERBOSE SetRenderList creating new texture (285 x 252)
...
VERBOSE getSetting(PreferredAudioRenderer)
2008-06-23 18:18:58.277 VERBOSE audio renderer filter: DirectSound: Realtek HD Audio output
2008-06-23 18:19:18.308 VERBOSE getSetting(ListGraphFilters)
2008-06-23 18:19:18.308 VERBOSE Graph contains the following filters:
2008-06-23 18:19:18.308 VERBOSE - MPEG-I Stream Splitter
2008-06-23 18:19:18.308 VERBOSE - SOURCE
2008-06-23 18:19:18.308 VERBOSE - DirectSound: Realtek HD Audio output
2008-06-23 18:19:18.308 VERBOSE getSetting(SaveGraphFiles)
2008-06-23 18:19:22.949 INFO DirectShowPlayerBase::playMusicFile(C:\$Media\TVvideo\gbnetradio-2.mp3)
...
2008-06-23 18:19:23.996 VERBOSE getSetting(ListGraphFilters)
2008-06-23 18:19:23.996 VERBOSE Graph contains the following filters:
2008-06-23 18:19:23.996 VERBOSE - DirectSound: Realtek HD Audio output
2008-06-23 18:19:23.996 VERBOSE - MPA Decoder Filter
2008-06-23 18:19:23.996 VERBOSE - MPEG-I Stream Splitter
2008-06-23 18:19:23.996 VERBOSE - SOURCE
2008-06-23 18:19:23.996 VERBOSE getSetting(SaveGraphFiles)
2008-06-23 18:19:31.074 INFO Key pressed: F4, Alt

The xml ...

<settings>
<DisableScreenSaver>False</DisableScreenSaver>
<EnableGetNowNext>True</EnableGetNowNext>
<StopOnChannelChange>True</StopOnChannelChange>
<ScanFullEPG>True</ScanFullEPG>
</settings>

The oddest thing is that I don't do anything to fix it ... just wait about 20 seconds, until the logo changes, and then press OK on the remote.

It may be that the decoder doesn't appear in the graph because the the mp3 file is empty. I'll try some more tests.

Thanks

Graham

[Graham]

It may be that the decoder doesn't appear in the graph because the the mp3 file is empty. I'll try some more tests.

I can run PVRX2 in a window and watch the folder containing the mp3 files in Explorer. I go to the plugin and select a channel, an mp3 file appears in Explorer and the channel begins to play.

I select a second channel and press OK on remote. The existing mp3 goes to 0k and no new file is created. The channel does not play. I wait 20 seconds for the channel logo to appear and press OK again and a new mp3 file is created and the channel begins to play.

Hope this helps.

Graham

[bgowland]

What specification is your machine (CPU speed, ram etc.)?

[Graham]

What specification is your machine (CPU speed, ram etc.)?

OS Name Microsoft Windows XP Home Edition
Version 5.1.2600 Service Pack 3 Build 2600
OS Manufacturer Microsoft Corporation
System Name TV2
System Manufacturer GBT___
System Model NVDAACPI
System Type X86-based PC
Processor x86 Family 15 Model 95 Stepping 2 AuthenticAMD ~1808 Mhz
BIOS Version/Date Award Software International, Inc. FG, 22/05/2007
SMBIOS Version 2.3
Windows Directory C:\WINDOWS
System Directory C:\WINDOWS\system32
Boot Device \Device\HarddiskVolume1
Locale United Kingdom
Hardware Abstraction Layer Version = "5.1.2600.5512 (xpsp.080413-2111)"
User Name TV2\Graham
Time Zone GMT Standard Time
Total Physical Memory 1,024.00 MB
Available Physical Memory 490.57 MB
Total Virtual Memory 2.00 GB
Available Virtual Memory 1.96 GB
Page File Space 2.31 GB
Page File C:\pagefile.sys

[bgowland]

I'm fairly certain that you're right about the decoder being missing from the pvrx2 playback graph is because the mp3 file is 0KB.

It seems to be a timing issue - the file would grow if everything was left to its own devices. The problem here is that (I think) pvrx2 is trying to restart playback of the new mp3 before it has started to be written. At that point, it stops its playlist which triggers a cleanup down the line. The fact the Now Playing panel continues to show the newly selected channel is a red herring (bug :o).

I think my pvrx2 process must be slightly slower in trying to play the new mp3 file by which time it has valid mp3 content. I'll need to do some tweaking and perhaps add a user setting for playback delay(s).

Is there a reason why you have StopOnChannelChange set to true? Does it cause problems when set to false?

Cheers,
Brian

[Graham]

Is there a reason why you have StopOnChannelChange set to true? Does it cause problems when set to false?

A long time ago, when DVB-T Radio was still in nappies, this thread hosted an exchange of messages about channel changes hanging when changing between muxes. That was me. I'm sorry but I can't remember what the outcome was ... it's an age thing.

I have StopOnChannelChange as true to be sure the that the mux problem, if it still exists, doesn't muddy the waters.

Your description of a timing problem seems to match the symptoms that I see. Would it be possible to put in a "filesize test" ...

Is mp3 > 0 bytes
if yes tell PVRX2 to play the file
if no wait 100 milliseconds then test filesize again.

Thanks
Graham

[bgowland]

A long time ago, when DVB-T Radio was still in nappies, this thread hosted an exchange of messages about channel changes hanging when changing between muxes. That was me. I'm sorry but I can't remember what the outcome was ... it's an age thing.

Yep - I'm with you on the 'age thing' - I can't remember either. I do know there was at least one other person who experienced the same thing which convinced me to add that setting.

I have StopOnChannelChange as true to be sure the that the mux problem, if it still exists, doesn't muddy the waters.

I'm racking my brains trying to think what's changed between the v1.2 Dvbtr.exe process and the v1.3 service to make such a difference. It seems that the service (on your machine at least) is returning an 'OK go ahead' result faster than the Dvbtr.exe process used to.

Would it be possible to put in a "filesize test" ...

Is mp3 > 0 bytes
if yes tell PVRX2 to play the file
if no wait 100 milliseconds then test filesize again.

Yep, already started to add the code for something similar. For the time being you'll have to live with a manual stop/start when changing channels. I may have a new upload for the wiki later tonight.

Thanks for the feedback / logs etc. they've been a big help.

Cheers,
Brian