No, I suspect it was to be more appropriate for broadcast applications, which usually have more frequent intra for channel switching.
Back in the day, 1/2 second or 12 frame GOPs were deemed essential for MPEG-2 digital TV to mimic analogue switching times, but I think that is long gone - now audio is switched first and then the video when possible, to give an illusion of immediacy. I think low bit rate channels could easily have intra periods of 2 or 3 seconds. I agree it's short for streaming applications, and could be longer. However, including a decent proportion of intra in the metrics is probably good. Regards Thomas -----Original Message----- From: Thomas Daede [mailto:[email protected]] Sent: Monday, March 02, 2015 10:20 PM To: Thomas Davies (thdavies) Cc: [email protected] Subject: Re: [video-codec] Test sequences, automated and otherwise Do you know if the 1-second keyframe interval was also for reasons of compute time? (It allows each GOP to be encoded in parallel). It unfortunately seems a bit short for many streaming applications, and also prevents rate control from being tested. At the moment, I run all codecs with rate control on in their constant quality mode. Perhaps this is not the right thing to do. On 03/02/2015 02:52 AM, Thomas Davies wrote: > The "Class A" JCT-VC sequences were originated at 4k or 8k and cropped > down for reasons of compute time. The 8k-originated ones (Nebuta and > SteamLocomotive) are very noisy and were shot with an early camera and > sensor. There wasn't much good 4k at the time HEVC started, and it > would certainly be good to get more. > > regards > > Thomas > > On 25/02/15 17:44, Thomas Daede wrote: >> The JCT-VC test set only includes three clips for video conferencing, >> which I don't think is sufficient. It also specifies a intra frame >> period of 1 second, which is not reasonable. It does not feature any >> 2160p test sequences either, which is a bit strange. >> _______________________________________________ video-codec mailing >> list [email protected] >> https://www.ietf.org/mailman/listinfo/video-codec > _______________________________________________ video-codec mailing list [email protected] https://www.ietf.org/mailman/listinfo/video-codec
