[Ffmpeg-devel-irc] ffmpeg.log.20180811

burek burek021 at gmail.com
Sun Aug 12 03:05:02 EEST 2018

[00:01:15 CEST] <iive> yuyv is packed format and these don't have many practical uses anymore.
[00:02:11 CEST] <iive> e.g. display overlays used to like them, because you get all pixel components in a single 32bit read. But video cards don't even have overlays anymore.
[00:40:08 CEST] <johnnny22> yeah, was thinking if the gpu could be leveraged maybe :)
[00:40:57 CEST] <johnnny22> the output could also be yuv422p (if i use v210)
[00:42:13 CEST] <johnnny22> my ffmpeg on 1 core seems to turn around 65% with v210 output, while around 75% with the other output mentionned before (yuyv).
[00:42:55 CEST] <johnnny22> was basically thinking about 'trying' to see if using the gpu to do the conversion could be an improvement, but idk how to do it either :o/
[00:43:41 CEST] <furq> scale_npp on nvidia
[00:43:48 CEST] <furq> assuming it supports those pixel formats
[00:54:07 CEST] <johnnny22> but i'm on vaapi
[00:57:31 CEST] <iive> i think that v210 is just bigger yuyv
[00:58:31 CEST] <furq> there's a scale_vaapi filter but it's not documented so idk if it does any format conversions other than to nv12
[01:09:25 CEST] <iive> once again, why is this conversion needed, is vaapi accepting only this format?
[07:24:33 CEST] <botik101> I do not know how to ask this without sounding like a moron, but how do i detect dpi of a movie?
[09:29:12 CEST] <Akeakamai> :D
[09:29:35 CEST] <Akeakamai> Hi
[09:30:11 CEST] <Akeakamai> ,0
[09:32:02 CEST] <Akeakamai> Does anybody has exp
[09:32:21 CEST] <Akeakamai> with h264_amf
[10:04:55 CEST] <johnnny22> iive: the reason is the endpoint either takes v210 or yuyv raw
[10:05:46 CEST] <johnnny22> endpoint = decklink device
[14:12:11 CEST] <Boobia> in filter_complex extractplanes I have an [u] scale=w=iw1
[14:12:16 CEST] <Boobia> what's iw1?
[14:20:52 CEST] <durandal_1707> Boobia: there is no iw1 in scale filter usage
[15:10:15 CEST] <luc4> Hello! I'm using ffmpeg to transcode and pipe the output to vlc for the streaming. When using mjpeg the result is a stream that does not respect the original speed of the video, probably cause it is missing the timestamps. Is it possible to somehow limit the speed of transcoding so that ffmpeg feeds vlc at the proper speed?
[15:12:14 CEST] <DHE> typically set something like -r or -framerate on the input to set a framerate. more details needed to be more specific
[15:15:11 CEST] <luc4> DHE: I see that -r sets the frame rate. But how can vlc know that value? Isn't mjpeg just a sequence of jpegs?
[15:25:46 CEST] <Bombo> can ffprobe show if a source stream is interlaced or progressive? i don't find the option
[15:26:40 CEST] <durandal_1707> Bombo: yes, if source have proper metadata
[15:27:08 CEST] <Bombo> luc4: why does vlc has to know? if you know, you can just add it somewhere
[15:30:03 CEST] <iive> Bombo, i think there is interlace detect filter, that checks the image for interlace artifacts
[15:31:47 CEST] <luc4> Bombo: so you say that setting "-r 1" should make ffmpeg output 1 jpeg per second?
[15:33:15 CEST] <Boobia> my stuff inside -filter_complex does not work if I try to put it on multiple lines with \
[15:33:51 CEST] <Boobia> it errors on indentation
[15:34:18 CEST] <Bombo> ah found it '-show_entries stream=field_order' shows field_order=progressive or field_order=tt
[15:35:04 CEST] <Bombo> iive: hmmm
[15:38:19 CEST] <Bombo> luc4: not sure, i think it depends on where you put that too, before -i or after... i think it sets the fps rate when playing or reading 1 fps then? better wait for an expert ;) or try it out
[15:41:01 CEST] <Bombo> iive: ah http://www.aktau.be/2013/09/22/detecting-interlaced-video-with-ffmpeg/ ;)
[15:45:26 CEST] <Bombo> 'SchleFaZ: Strippers vs Werewolves TELE 5 2018-08-10 22-00-04.mpg: Protocol not found'
[15:46:16 CEST] <Bombo> oh lol it detects the : and thinks its a protocol
[16:03:26 CEST] <DHE> prefix it with file:
[16:07:47 CEST] <Bombo> DHE: oh nice trick, thx ;)
[16:09:02 CEST] <Bombo> ffprobe -select_streams v:0 -show_entries "frame=pkt_pts_time,pkt_duration_time,interlaced_frame" file:"$FILE" -pretty -print_format csv -v error -of csv="s=,:p=0"
[16:09:22 CEST] <Bombo> hm i get extra \n when scanning an interlaced file for some reason
[18:57:30 CEST] <the_gamer> i want to have videopictures from second 10 going for 8 seconds. ffmpeg -ss 00:10:00 -i P1000250.MP4 -t 18 bilder/lennygross%04d.png #and others always say output file is empty. how to do it?
[19:00:42 CEST] <the_gamer> -t duration (input/output)
[19:00:43 CEST] <the_gamer> When used as an input option (before -i), limit the duration of data read from the input file.
[19:00:43 CEST] <the_gamer> When used as an output option (before an output url), stop writing the output after its duration reaches duration.
[19:00:49 CEST] <the_gamer> does not work for me. but why
[19:04:50 CEST] <Blacker47> the_gamer, maybe try -ss after -i <infile>.
[19:06:01 CEST] <Blacker47> and -to, not -t
[22:26:48 CEST] <speeedy> hi, how do I remove track names with ffmpeg ? from a mkv
[22:26:59 CEST] <speeedy> is there a tag that does it automatically
[22:40:25 CEST] <barhom> speeedy: not ffmpeg, but https://mkvtoolnix.download/doc/mkvpropedit.html ?
[23:00:57 CEST] <speeedy> thanks
[00:00:00 CEST] --- Sun Aug 12 2018

More information about the Ffmpeg-devel-irc mailing list