Re: [backstage] HD Videocamera advice please...
IMHO, plus points for the Sony include no-light nightshot for your Blair Witch-style fun, and a (albeit low-rent) Carl Zeiss lens. The audio jack is the main selling point for me though. ...the GOP length will affect the ability to edit the output. I've never really understood GOP (I know it's to do with interlacing, right?) - could you point me in the direction of a clear explanation please? No, nothing to do with interlacing (i.e. you have a GOP with any MPEG interlaced or progressive video) It is the Group of Pictures. In MPEG you can encode each frame as I-Frames, P-Frames or B-Frames. I-Frames have the complete image, P-Frames are predicted based upon changes from an I-Frame or previous P-Frame. B-Frames are similar to P-Frames, but bi-directionally predicted (n.b. this implies out of order frame encoding in the encoder) from I, P and B-Frames. A GOP is a sequence of I, P and B-Frames e.g. IBBPBBPBBPBB The GOP length is the number of frames between successive I-Frames. A long GOP length will, for example, cause a delay on video appearing on changing channels on a STB or, as editing cuts can only start from an I-Frame will mean you can't do frame accurate editing. Broadcast contributions e.g. DV, use I-Frame only codecs to allow frame accurate editing. Usually when taped MPEG is transferred to an online medium, the frame headers have trick mode data added to them to allow the frames to be found quickly for faster reconstruction. -- -- *Simon Thompson MEng MIET * Research Engineer (Electronics) PRINCE2TM Registered Practitioner *BBC Future Media and Technology* -- Brian Butterworth http://www.ukfree.tv - independent digital television and switchover advice, since 2002
Re: [backstage] HD Videocamera advice please...
Simon Thompson wrote: The GOP length is the number of frames between successive I-Frames. A long GOP length will, for example, cause a delay on video appearing on changing channels on a STB or, as editing cuts can only start from an I-Frame will mean you can't do frame accurate editing. I disagree with can't - the Sony XDCAM EX1 is a serious camera intended for broadcast use that uses long-GOP MPEG2. However, editing is indeed harder since the software needs to be clever about how it handles the content. You potentially have to decode a fair number of frames to show the one you want, and (unless re-rendering) you need to keep up to the previous I-frame before any edits made in your source material throughout the editing process. Final transcoding is awkward too. If you intend to output to another MPEG-2 then you either have to totally re-render the content to have new I-frames (but with associated quality losses) or attempt to piece together the original GOPs for the edit, only generating new sections around edit points. The majority of production houses [1] are still using I-frame based systems - DV/Digibeta/HDCAM - but with the current trends towards MPEG2-based formats - HDV/P2 - it is going to be interesting to see how different types cope with the issues of non-I-frame editing. Some long-timeframe productions will have the opportunity to re-render to a I-frame format at ingest (typically MJPEG), others (current affairs / sports) will have to deal with the formats throughout their workflows as they are. -jeremy [1] Televisual Aug '08 Production Survey (Current usage: 70% Digibeta, 68% DV, 49% HDV, 45% HDCAM) - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/
Re: [backstage] HD Videocamera advice please...
Jeremy James wrote: Simon Thompson wrote: The GOP length is the number of frames between successive I-Frames. A long GOP length will, for example, cause a delay on video appearing on changing channels on a STB or, as editing cuts can only start from an I-Frame will mean you can't do frame accurate editing. I disagree with can't - the Sony XDCAM EX1 is a serious camera intended for broadcast use that uses long-GOP MPEG2. However, editing is indeed harder since the software needs to be clever about how it handles the content. You potentially have to decode a fair number of frames to show the one you want, and (unless re-rendering) you need to keep up to the previous I-frame before any edits made in your source material throughout the editing process. BBC RD did some work on this a few years back - here's a white paper from 2006, for example, if anyone's interested: http://www.bbc.co.uk/rd/pubs/whp/whp138.shtml The basic finding was more or less what Jeremy said - that long-GOP video encoding makes life harder for the people who write video editing software, but doesn't make frame-accurate editing impossible by any means. You have to trade the advantages and disadvantages of recording with a long-GOP codec according to circumstances - a state of affairs that will probably surprise nobody. :-) S - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/
RE: [backstage] HD Videocamera advice please...
Thanks Steve for clearing the whole thing up. I generally only edit the top and tail of the footage if at all, so a flash based h.264 camcorder makes sense. Having a HD camera in my bag everyday has been handy sometimes. BBC RD did some work on this a few years back - here's a white paper from 2006, for example, if anyone's interested: http://www.bbc.co.uk/rd/pubs/whp/whp138.shtml The basic finding was more or less what Jeremy said - that long-GOP video encoding makes life harder for the people who write video editing software, but doesn't make frame-accurate editing impossible by any means. You have to trade the advantages and disadvantages of recording with a long-GOP codec according to circumstances - a state of affairs that will probably surprise nobody. :-) - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/
RE: [backstage] HD Videocamera advice please...
If I was buying one now, I would get the Sanyo Xacti HD1010. But I love flash media and am not so bothered about the quality of the actual footage. I also love the 300fps mode. http://www.engadget.com/2008/06/05/sanyos-xacti-hd1010-1080i-camcorder-shoots-300fps-slow-mo/ Cheers Ian Forrester This e-mail is: [x] private; [] ask first; [] bloggable Senior Producer, BBC Backstage Room 1044, BBC Manchester BH, Oxford Road, M60 1SJ email: [EMAIL PROTECTED] work: +44 (0)2080083965 mob: +44 (0)7711913293 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Tonge Sent: 29 September 2008 22:56 To: backstage@lists.bbc.co.uk Subject: Re: [backstage] HD Videocamera advice please... ...had bad experience with sometimes the picture breaking up... Never had any problems with ours: try using better quality tapes and striping them first (I always do it but videophiles disagree on this). Jim - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/ - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/
Re: [backstage] HD Videocamera advice please...
linked article from that page: Sanyo's line of Xacti camcorders have traditionally looked mighty fine on paper, but for one reason or another, expectations haven't exactly been met on the previous iterations. The firm's latest pistol-grip device yet again looked superb at a glance, but TrustedReviews found that the VPC-HD1000 still wasn't able to live up to its claims. On the upside, reviewers found the design to be much improved, and the Full HD recording abilities were drooled over as well. Still, the crew couldn't help but be disappointed in the paltry four-megapixel CMOS sensor, and while it did perform better than its predecessors as a camcorder, the optical zoom was tagged as slow, colors seemed slightly oversaturated and you'll still need plenty of light in order to get halfway decent results. Furthermore, it was noted that quick changes in scenery caused noticeable pixilation, and shooting in low-light introduced a lot of grain. Overall, the HD1000 wasn't totally slammed nor lifted up on a pedestal, but we'd probably hold off on this unless you're cool with a jack of two trades, but master of neither. Mind you, this is from Engadget, who get nice stuff given to them gratis on daily basis... IMHO, plus points for the Sony include no-light nightshot for your Blair Witch-style fun, and a (albeit low-rent) Carl Zeiss lens. The audio jack is the main selling point for me though. ...the GOP length will affect the ability to edit the output. I've never really understood GOP (I know it's to do with interlacing, right?) - could you point me in the direction of a clear explanation please? Thanks. Jim - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/
Re: [backstage] HD Videocamera advice please...
2008/9/29 Matt Barber [EMAIL PROTECTED]: I'd like to hear any suggestions or comments. Out of your price range and needs, but the Red ONE is fun to know about :-) http://en.wikipedia.org/wiki/RED_Digital_Camera_Company - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/
Re: [backstage] HD Videocamera advice please...
Dave Crossland wrote: 2008/9/29 Matt Barber [EMAIL PROTECTED]: I'd like to hear any suggestions or comments. Out of your price range and needs, but the Red ONE is fun to know about :-) http://en.wikipedia.org/wiki/RED_Digital_Camera_Company Ag (sound of drooling from my mouth) - I read about that in Wired, then that week, actually saw one being carried around briefly in Ostende. It is such a nice bit of kit, interesting story behind it too. But alas... slightly out of my range :)
Re: [backstage] HD Videocamera advice please...
Got a lower version of the Sony HDR-HC9E at work - last year's model. Pretty good for a Handycam: CMOS sensor, audio in. 'Spose it depends if you want DV/HDV or flash cards. For the price I'd probably go with DV tape though. Got 'em at Amazon for £645, but try Visual Impact Northern - their sales guy Rob usually sorts me out with a really good price. Good luck. Jim On 29 Sep 2008, at 18:54, Matt Barber wrote: Hi everyone, wondering if I can ask your advice. I have been interested in getting myself either a new lens for my Canon 350D or an HD video camera for some time, and thought it's time to get one or the other in the next month or two. Not looking for a pro-sumer camera, because it's out of price range and too big - something hand-held. Around £550, maybe 650 if the features or quality gains are unmissable. Have looked at these: Panasonic HDC HS9 [1], with hard disk, small form factor and 3CCDs. Unsure if 3CCDs in this case is a gimmick because they're so small. I'm not a fan of interpolation but with the money, I don't expect full 1080 from all sensors :). No focus ring.. Panasonic HDC SD100 [2], as above, no hard disk, focus ring (good feature for me), cheaper. But have to buy the massive SD card. Really quick startup time. Also looked at a canon with one full sensor rather than 3CCDs... So any thoughts? What have you used? I'd like to hear any suggestions or comments. Many thanks, Matt [1] http://www.trustedreviews.com/camcorders/review/2008/03/15/Panasonic-HDC-HS9-Camcorder/p1 [2] http://www.trustedreviews.com/camcorders/review/2008/09/26/Panasonic-HDC-SD100/p1
Re: [backstage] HD Videocamera advice please...
Jim Tonge wrote: Got a lower version of the Sony HDR-HC9E http://www.sony.co.uk/product/hdd-hdv/hdr-hc9e/tab/technicalspecs#tab at work - last year's model. Pretty good for a Handycam: CMOS sensor, audio in. 'Spose it depends if you want DV/HDV or flash cards. For the price I'd probably go with DV tape though. Got 'em at Amazon for £645, but try Visual Impact Northern http://www.visuals.co.uk/VisualImpactNorthern/ - their sales guy Rob usually sorts me out with a really good price. Good luck. Jim Thanks Jim, I will have a look. I had some miniDV standard-def cameras before - but had bad experience with sometimes the picture breaking up, was thinking a hard disk model would solve that and also give me random access which would be great. Just considering that lowers my range considerably though so will give tape a look, thanks for the suggestion :) Matt
Re: [backstage] HD Videocamera advice please...
...had bad experience with sometimes the picture breaking up... Never had any problems with ours: try using better quality tapes and striping them first (I always do it but videophiles disagree on this). Jim - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/
