Re: [FFmpeg-user] Syncing stereo videos - what method?
Jesper Taxbøl jesper at taxboel.dk writes: I am trying to sync two videos recorded simultaniously from a stereo setup. This should work with -itsoffset and specifying the input file twice, something like (untested): $ ffmpeg -i A.mp4 -itsoffset 0.75 -i A.mp4 -map 0:0 -map 1:1 -codec copy out.mp4 Carl Eugen ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] overlay with video offset not starting audio with same offset
On Fri, Aug 28, 2015 at 23:03:10 +, Chad Horton wrote: I¹ve tried adding it in various places, each throwing errors. You're neither telling us what you tried nor what the errors were? Good luck getting help. ;-) SCNR, Moritz P.S.: I hadn't understood the original problem fully, so I haven't delved into helping. ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] [FFmpeg-devel] ffplay buffer
On Fri, 28 Aug 2015, Dan Gordon wrote: I’m working on a frame accurate stream switch. My current iteration is using vapoursynth to serve frames to ffplay. I have the vapoursynth script set up to take a keyboard input and then change to stream without skipping forward to the next iframe. There is a 500 ms delay between the keyboard action and the video switching. The good news is that it is frame accurate, the bad news is that 500 ms is a LONG delay. My initial assumption was that ffplay had a buffer in place but I dropped the MIN_FRAMES to 5 from 25 and the delay is still present (and still at ~500 ms). I know this isn’t a vapoursynth forum but I’m trying to eliminate ffplay as the source of the delay. When ffplay is receiving data from a yuv4mpegpipe with MIN_FRAMES set to 5, how much of a delay is there between receiving the frames and displaying them? What are the EXTERNAL_CLOCK_MIN_FRAMES AND EXTERNAL_CLOCK_MAX_FRAMES for? here’s my command vspipe -y4m script.vpy - | ffplay pipe: -sync video Thanks This thread is more suitable to ffmpeg-user, so I replied there. Anyway, based on what you wrote, I guess you want to minimalize latency, but buffer sizes is only part of that. Probably the initial stream probing is the main factor in the latency you experience (ffplay only starts playing the source after probing it, and this will cause a delay), so consider decreasing probesize. If you use the -sync ext mode, and hack ffplay to use realtime mode for pipe input (check is_realtime function in the code), then ffplay will increase/decrease clock speed based on buffer fullness, and EXTERNAL_CLOCK_MIN_FRAMES and EXTERNAL_CLOCK_MAX_FRAMES controls when to increase or decrease the clock speed in this case. This can be used to minimalize latency, because even if initially there is plenty of data in the buffers because of probing, after a few minutes ffplay will catch up thanks to the increased master clock. This may or may not be suitable for your needs... Probably you will never achieve 0 frame latency, because ffplay has a buffer on the decoded frame level as well, see VIDEO_PICTURE_QUEUE_SIZE. Regards, Marton ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] overlay with video offset not starting audio with same offset
I didn't provide my attempts because I was randomly throwing adelay and then atrim into my command and nothing worked. My hope is that someone could show me how to do it properly with my current command and adding in the atrim and/or adelay filter. On Aug 29, 2015, at 4:55 AM, Moritz Barsnick barsn...@gmx.net wrote: On Fri, Aug 28, 2015 at 23:03:10 +, Chad Horton wrote: I¹ve tried adding it in various places, each throwing errors. You're neither telling us what you tried nor what the errors were? Good luck getting help. ;-) SCNR, Moritz P.S.: I hadn't understood the original problem fully, so I haven't delved into helping. ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] overlay with video offset not starting audio with same offset
On 8/29/15, Chad Horton chor...@hotsalsainteractive.com wrote: I didn't provide my attempts because I was randomly throwing adelay and then atrim into my command and nothing worked. My hope is that someone could show me how to do it properly with my current command and adding in the atrim and/or adelay filter. This works for me: ffmpeg -i ~/matrixbench_mpeg2.mpg -itsoffset 00:00:20.000 -i ~/GoneNutty.avi -lavfi scale=640:512,vstack;[0:a]atrim=20[a],[1:a][a]amix output.avi ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
[FFmpeg-user] Stats
Hi! Is there a way to extract stats of encoding and decoding video into csv or similar format? I want to do several graphics to compare efficientcy in my project, but I don't know how to do... Thank you all ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] Syncing stereo videos - what method?
Thanx for your input. I did not know the -itsoffset flag. I think my problem was that I was trying to save the recoding via the copy class. What ended up working for me was this. /usr/local/bin/ffmpeg -y -loglevel panic -ss 1.161397 -i 3.mp4 -t 15 _3.mp4 I could not make the itsoffset flag do the trick. Kind regards Jesper 2015-08-29 15:49 GMT+02:00 Carl Eugen Hoyos ceho...@ag.or.at: Jesper Taxbøl jesper at taxboel.dk writes: I am trying to sync two videos recorded simultaniously from a stereo setup. This should work with -itsoffset and specifying the input file twice, something like (untested): $ ffmpeg -i A.mp4 -itsoffset 0.75 -i A.mp4 -map 0:0 -map 1:1 -codec copy out.mp4 Carl Eugen ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user -- Jesper Taxbøl +45 61627501 ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
[FFmpeg-user] Frame interpolation in FFmpeg
Hi guys: Can any FFmpeg experts tell me if FFmpeg can do any sophisticated frame interpolation? If so, what would be some suggested settings to try? I am developing a media player based on FFmpeg and want to improve smooth through frame interpolation. -- Damon Hu Email: hudap...@baidu.commailto:weihu...@baidu.com Tel: 86-10-50819178 Mobile: 18612523725 ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
