View Full Version : Bt8x8 Capture - Interlaced or Progressive
30th October 2008, 01:37
I've been searching through the forum, but I couldn't find any definitive answer... When using one of these cards (with btwincap driver), is deinterlacing needed?
I've been experimenting with it, and it seems when deinterlacing on nsvenc the image is smoother without those typical motion blurs of interlaced sources... but it may be a placebo effect of knowing it is activated :)
Thanks in advance.
Edit: The card is a Pinnacle PCTV (bt878) and the source is a satellite receiver connected to the composite input (SCART to composite)
30th October 2008, 02:56
not a placebo effect. If the source material is interlaced, deinterlacing will remove interlacing (well, that was self evident of me!! ;) )
but no ... the picture will be better quality with de-interlacing
31st October 2008, 15:39
Just finished setting up and though it would be helpful for someone else :)
So lets see... starting from the beginning...
I'm capturing from a satellite receiver (PAL) via composite video and 2 RCA cables for sound, connected to the soundcard's linein (a C-media onboard card, which I had to patch a nasty bug, info here (http://www.cmedia.com*****forums/viewtopic.php?p=4480&sid=d8a6b09ae7b1711567a5eaaad139efdd))
Next, I installed the btwincap driver for my tv tuner card, and ffdshow for deinterlacing and resize filters.
After some testing and web research, I've settled with capturing at 768x576 (YUY2) through ffdshow, deinterlacing the signal with TomsMoComp (swap fields on, 5, vertical filter), the swap fields is needed for PAL from what I've read... Then the resize to 384x288 (half) via Simple Resize (acceptable quality and fast), and finally the encoding:
Video - x264vfw, 322kbps ABR, Subme 6, Me hex (can't use the umh for cpu reasons...), threads 3 (P4 3.2GHz HT Prescott)
Audio - LAME MP3 48kbps ABR (32kbps min, 64kbps max), before you say anything :p I've tried AAC+ from the shoutcast dsp plugin, but I got skipping audio (?!), and somehow MP3 sounds pretty acceptable with this settings.
That gives me a stream with 370kbps ABR combined, which looks and sounds "awesome" :)
Maybe this helps someone trying to setup NSV...
And as a last word, NSV is a really great format, and the shoutcast server is very portable and low on resources usage... save for the bandwidth usage :D
Sorry for any typos, but english isn't my primary language.
2nd November 2008, 01:22
I probably would just capture at the resolution you were going to transmit at. On a "P4 3.2GHz HT Prescott" you are going to get away with the software resizing, but you are probably just wasting CPU.
I know on the brooktree chipsets (in NTSC) that I've used that the output @320X240 or 352X240 isn't interlaced.
3rd November 2008, 22:23
yup rockouthippie is correct, capturing at half resolution should already be progressive, so you wont waste resources on deinterlacing or resizing
5th November 2008, 00:36
I'm capturing now at 640x288 and resizing to 384x288 (4:3 AR), this resolution doesn't exist on capture pin settings, only 352x288... but yeah it is much more fluid now, and there is no need for software deinterlacing, thanks for the tip :)
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