I see weird things when I try to playback an mpeg containing recorded
closed caption VBI data. I checked that the data in the mpeg file is
in transmission order, but what I get out seems to be randomized. It's
all there, but in the wrong order.
I cannot reproduce this with PAL teletext or WSS VBI data, it's coming
in at the correct order.
Can someone with a PVR350 in NTSC country test the following for me?
- Download ivtv-0.3.7g (see my upload message just now)
- Apply attached patch to ivtv-irq.c
- Compile and install
- Tune to a channel containing close captions
- Set up VBI embedding: ivtvctl -b cc -w cc -x 1
- Go to the test directory and run: vbi /dev/vbi4
- In another console run: cat /dev/video0 >/dev/video16 (10-15 seconds is
enough)
Now check the kernel log. It is the offset value at the end that concerns me.
It is the offset in the memory area the VBI data from the MPEG file is placed
by the firmware. It should be increasing until a certain point and then jump
back to the beginning. Instead, what I see is this:
offset 0x0019d068
offset 0x0019e8a8
offset 0x0019eeb8
offset 0x0019e298
offset 0x0019fad8
offset 0x001a00e8
offset 0x0019f4c8
offset 0x001a06f8
offset 0x001a1318
offset 0x001a1928
offset 0x001a0d08
offset 0x001a2548
offset 0x001a2b58
offset 0x001a1f38
offset 0x001a3778
offset 0x001a3168
offset 0x001a4398
offset 0x001a49a8
Note that many offsets are out-of-order. And it is not hard to imagine what
that does to your closed captions. Can anyone verify this?
Thanks,
Hans
--- ivtv-irq.c~ 2005-08-20 17:39:10.000000000 +0200
+++ ivtv-irq.c 2005-08-20 17:39:28.000000000 +0200
@@ -827,7 +827,7 @@
size = ivtv_read_reg(itv->dec_mem + itv->vbi_dec_start + 4);
size += 8;
pts_stamp = 0;
- IVTV_DEBUG_DMA(
+ IVTV_INFO(
"DMA/VBI-Reinsertion type 0x%08x, size 0x%08x, offset 0x%08x\n",
streamtype, size, offset);
}
