Win7x64 Sound issues

[butterstick]

Hi All, I was hoping someone might be able to help me out. I have the newest version of GBPVR running on a new install of Win7x64RC1. Everything is good, except I cannot get any sound from GBPVR on live TV or on playback. I know the sound is there because everything else plays sound fine, VLC, WMP, Flash, etc. The recordings GBPVR makes playback with sound in other programs I just can't seem to get sound to come out of GBPVR. The sound device is a Radeon 4850 with sound out HDMI. It is set to the default device (onboard sound is disabled in the BIOS). I've tried different Audio Renderer's under Playback but nothing seems to be working. Thanks in advance for any help.

[whurlston]

Download AC3Filter. Make sure it's not the 64 bit version (GBPVR is a 32 bit app).

[butterstick]

Perfect. I downloaded AC3Filter (Full) installed and playback and live TV worked after a reboot without changing any settings in GBPVR. Many, many thanks Whurlston. That was driving me a little nuts.

I'm not sure what it "fixed"? I've been reading the forums here for about a year now and I still don't really understand the difference between a mux, codec, and filter. I know GBPVR doesn't really do any of the capture, processing, or playback but relies on other things to do that. Do they match up at all? Like capture is done with a card and its driver, processing would be the mux plus a codec if you were converting the format, and filters are for playback?

[whurlston]

Sorry for the short post earlier. The problem was that you did not have an AC3 capable decoder that GBPVR could use. VLC uses it's own internal decoders and WMP uses the Microsoft DTV Decoder. The Microsoft decoder will only decode Dolby Digital when used in Microsoft applications so GBPVR was not able to use it for AC3.

[dennit]

I've been reading the forums here for about a year now and I still don't really understand the difference between a mux, codec, and filter. I know GBPVR doesn't really do any of the capture, processing, or playback but relies on other things to do that. Do they match up at all? Like capture is done with a card and its driver, processing would be the mux plus a codec if you were converting the format, and filters are for playback?

The term "mux" is short for a multiplexer. The tuner card you use delivers transport stream packets (TS packets), which can be used directly for live TV, but which need to be assembled into an mpeg file. That's the job of the mux. The mux is used only for recording.

The term "codec" is short for encoder-decoder. GBPVR only does decoding (except when doing format conversion). It doesn't need to do encoding, because that was done when the TS packets were created. The codecs are needed for playback. Using the mux, GBPVR builds ts, mpg or dvr-ms format files. All of these are variations of the mpeg format that was in the original TS packets. The codec is needed to decode what the mux built and the mpeg inside the TS packets that the mux put together.

The term "filter," afaik, is a Microsoft word for a chunk of software that does one of the jobs needed in handling audio/video files, particularly through directshow in the case of GBPVR. It can be the mux or the codec discussed above. It could be a "splitter," which separates the audio from the video. It can be a "renderer," which sends it to a screen. There are various names for what the "filters" do. "Filters" have input pins and output pins so you can connect them one to another. You can test a string of filters in a program called graphedit. You can look to see what "filters" are used by GBPVR in the logs, then recreate that string in graphedit and see why it isn't working or whether some other codec or renderer would work better. Microsoft has a way of automatically picking filters using a number called the "filter merit" that is assigned to each "filter."

If you tell GBPVR to use the system default, it will ask Microsoft to make this automatic choice. If you tell GBPVR to use a particular filter, it will override this automatic choice. You can change the filter merit for any filter to control the automatic choice, or use the GBPVR override. The latter is the most common method.