Andrew Haley wrote: > On 10/14/2010 12:33 PM, Alan Cox wrote: >> On Thu, 14 Oct 2010 06:29:10 -0400 >> Tod Thomas <fr33zone@xxxxxxxxx> wrote: >> >>> I remember reading some time ago that VHS was a proprietary standard >>> and without special equipment it was difficult to transfer it to other >>> media. I'm pretty sure I heard within the last couple of years that the >>> VHS standard was retired, or its patent ran out, or something. I >>> expected someone would eventually pick up on that and develop an open >>> source process for transferring old VHS content to DVD. Is there >>> something likes this? Am I dreaming? >> You need a capture card for own stuff. It may be macrovision >> protected so you can't do it without either other trivial bits (which I >> believe are now illegal in the USA) or a tv capture card that doesn't get >> confused by it. > > I have a need for this (an old wedding video). I'd be interested to know > if anyone here knows of a tv capture card that works well with Fedora. The quality will not be great, but that is just a limitation of the tape. I mean, you will never get something better than what is actually coded in the tape; the problem is that what appears good on a TV appears bad on a modern good monitor. Anyway, I have done the conversion for a lot of homemade videos. Hardware: any BT848/BT878 board or similar (Philips SAA7134). Most analog capture board use these chips. There are web pages listing commercial models and chipset used. With one of these boards, you connect video composite and audio from the VCR to the PC. (audio goes into line-in of the soundcard if the capture board is video-only). You then adjust the audio level to avoid clipping. You capture video and audio using one of the available tools. I usually run command-line mencoder; compressing video while capturing is NOT a good idea, better to capture everything lossless and then do some processing. I use a lossless codec, called ffhuffyuv, I think (sorry, I can not access to my scripts at the moment), which will save data with no degradation (it is like zip, not like jpeg). I have no problems doing this in 720x576 on an Athlon XP2400+ and one 60GiB disk (hardware older than 6 years). The final file (a lot of gigabytes) can then be loaded in avidemux for postprocessing and rendering. First thing is discarding initial and final dead seconds. I always use a chroma stabilization filter (VHS always likes to flicker between one green-ish frame and one violet-ish frame). It is seldom needed to use some other filter (color enhancement or denoising). If you decide to scale the video you have to handle the interlacing issue: if you resize to <=50% of height, the best thing to do is to discard one of the fields. If you do not rescale you can try to compress in interlaced format (activate the option in the parameters of your video codec). Another option is to deinterlace: I go from 25i to 50p with the yadif filter when I want to maintain highest quality. Finally, the encoding part. For "archival" stuff I use MPEG4 with a low fixed quantizer (such as 3 or 4). If you want small files you can go with the usual 2-pass VBR methods. If you want DVD, you have to go to MPEG2 and do addition steps (VOB files, menus, dvdauthor ...). Audio is easy; mp3 or vorbis, it is difficult to get it wrong (mp2 for DVDs). Problems I have encountered in my experience: 1) lost frames when capturing; this is not caused by CPU or disk saturation but by failure of the video chip in detecting the VHS start-of-frame sync; if you pass the vcr_hack option to the bttv module the problem is solved (but you lose a few video lines at the bottom of the frame, something like 4 or 8). 2) audio and video go out of sync; actually never happens with mencoder as it will compensate by skipping or duplicating a frame. The process takes a long time (3 hours of recording may need 3-8 hours of additional processing, depending on your hardware and what you do), but it can run unattended, so you don't mind. The quality is not as bad as often described. You will hear that a time base corrector hardware is needed to have good results, but not many people know that the BT chips actually have a sort of TBC inside. I can give you more details if you want. -- Roberto Ragusa mail at robertoragusa.it -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
