ffmpeg doesn't record sound from WinTV.

Steve O'Hara-Smith steve at sohara.org
Mon Jan 2 02:22:35 PST 2006

On Mon, 2 Jan 2006 03:46:02 +0100
"Frank J. Beckmann" <frank at barda.agala.net> wrote:

> hat tells me 
> that the mixér settings are ok but the tv card does not send sound then I use 
> ffmpeg (or nuppelvideo).

	ffmpeg and nuppelvideo both use the same code to talk to the bktr
device, it relies on the sound being activated by opening the tuner device
which usually does the job. I see something possible in the xawtv code - 
could you try two things (in this order) please.

	First try rebooting and using ffmpeg *without* first running
xawtv (or motv) - you can tune the signal by setting the environment
variable BKTR_FREQUENCY to a frequency in megahertz. I have a suspicion
that xawtv is leaving the sound muted, every bktr card I have seen powers
up with the sound unmuted - this will test my suspicion.

	Second try applying this patch in /usr/ports/multimedia/ffmpeg
and then rebuilding and reinstalling ffmpeg. Let me know how you get
on - if it works I will try and get the patch committed and pushed up
to ffmpeg (grab_bsdbktr.c is now in ffmpeg CVS).

--------------------- Cut Here and your monitor will explode --------------
Index: files/grab_bsdbktr.c
RCS file: /ncvs/ports/multimedia/ffmpeg/files/grab_bsdbktr.c,v
retrieving revision 1.9
diff -u -r1.9 grab_bsdbktr.c
--- files/grab_bsdbktr.c        6 Jun 2005 02:05:01 -0000       1.9
+++ files/grab_bsdbktr.c        2 Jan 2006 10:15:50 -0000
@@ -171,6 +171,11 @@
                perror ("METEORSINPUT");
                return -1;
+       c = AUDIO_UNMUTE;
+       if (ioctl(*video_fd, BT848_SAUDIO, &c) < 0) {
+               perror ("BT848_SAUDIO");
+               return -1;
+       }
        *video_buf = (u_int8_t *) mmap((void *) 0, width*height*2,
                PROT_READ, MAP_SHARED, *video_fd, (off_t) 0);
        if (*video_buf == MAP_FAILED) {
--------------------- Cut Here and your monitor will explode --------------

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