On Tuesday 05 October 2004 00:51, Steven M. Schultz wrote: > > I think it's a pity lavtools doesn't support any easily streamable > > format. That would make building timeshifters easier. > > I'm confused (or missing something ;)). How does 'streaming' make > 'timeshifting' easier? Streaming is (to me) a distribution mechanism > for viewing encoded (mpeg-2 or mpeg-4) content. It takes a pretty > fast network connection to stream the other formats (uncompressed > standard definition "video" is 124Mb/s as I recall). > > For timeshifting what's needed is a good sequential I/O file format. > Something like 'raw DV' or perhaps IYUV (or the YUV4MPEG2 variant) - > both use fixed record sizes so there's no indexing involved (and since > you know the frame rate and size you can seek by time using simple > arithmetic ;)). No filesize limits with those formats.
Ok, sequentialable format, then. :) Streaming to me means a format you can tap into anywhere and begin playing at the next convenient frame. RIFF is not such a format, as you need the whole file to be able to sync into it. (Well, not really, but I don't know of any players that can play the middle third of an avi file without seeing at least the beginning first.) > If you're capturing to do encoding later then 'streamability' isn't > needed but good sequential I/O is important. Quicktime should be fine > for that. AVI format is not all that good since it has the 2GB limit > and the indexing issue. Startup time has never been an issue for me with avi files. The 2GB limit is moderately easily worked around using the multiple files feature of lavrec and some "clever" scripting. Well, it's a pain to feed mencoder the resulting files, but hey... :) Quicktime doesn't, in itself, solve the question of timeshiftability. It may be easier to seek in, but if I haven't misunderstood the format completely, you still want to make it easier on yourself by using complete files, which makes it a little tricky to implement a time-limited, neverending circular buffer. If that's comprehensible. I'm talking about a box that's able to grab a continuous stream into a buffer of, say, ten hours' length, and then destroy any frames older than ten hours, making room on the disk for more video. It's a bit tricky, but it should be doable. With a modified lavplay, it might even be possible to do using avi format. Quicktime might be easier; I don't know, as I haven't investigated that route enough. /Martin ------------------------------------------------------- This SF.net email is sponsored by: IT Product Guide on ITManagersJournal Use IT products in your business? Tell us what you think of them. Give us Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more http://productguide.itmanagersjournal.com/guidepromo.tmpl _______________________________________________ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
