[Ffmpeg-devel-irc] ffmpeg.log.20151012

burek burek021 at gmail.com
Tue Oct 13 02:05:01 CEST 2015

[00:56:45 CEST] <BasisBit> uhm, I just wanted to try current ffmpeg 2.8 windows build (Zeranoe's build) and I saw that the lib* version numbers in the README.txt seem to be outdated (->ffmpeg2.7)
[01:27:19 CEST] <Nickwiz> Playing around with the "drawtext" filter. Is there a way to print absolute value of width and height? For example: text=${expr\\:w}, gives i.e. "720.000000", I would like "720"
[01:27:43 CEST] <Nickwiz> Have tried using expr:abs(w), but gives same result
[01:28:00 CEST] <PovAddict> absolute value means turning negative numbers into positive
[01:28:08 CEST] <PovAddict> nothing to do with decimals
[01:30:08 CEST] <Nickwiz> yes, sorry
[01:31:07 CEST] <PovAddict> I'm not sure how to fix that; if you round it to the nearest integer, drawtext will still print the .00000
[01:31:31 CEST] <PovAddict> eg. if you use round(123.456789) you'd get 0.000000
[01:33:47 CEST] <Nickwiz> yes, tried ceil and floor.
[01:34:07 CEST] <PovAddict> also, you meant %{} instead of ${} right?
[01:34:23 CEST] <Nickwiz> yes
[01:35:20 CEST] <PovAddict> try %{eif:w:d}
[01:35:31 CEST] <PovAddict> eif is shorthand for expr_int_format
[01:36:12 CEST] <Nickwiz> Thanks, that did it!
[01:37:28 CEST] <Nickwiz> Somehow managed to overlook that expansion function.
[02:42:03 CEST] <Zeranoe> BasisBit: How do you figure they are outdated?
[02:43:00 CEST] <BasisBit> rightclick on the DLLs and look at the version information / file tags
[02:43:21 CEST] <Zeranoe> BasisBit: For the git builds or the 2.8 release?
[02:43:29 CEST] <BasisBit> the git builds
[02:43:33 CEST] <PovAddict> yay
[02:43:42 CEST] <PovAddict> too much open source software doesn't bother filling in DLL version information
[02:43:52 CEST] <Zeranoe> BasisBit: What are you comparing the versions to
[02:44:13 CEST] <BasisBit> to the version numbers stated in the readme.txt
[04:29:33 CEST] <Prelude_Zzzzz> hey guys.. anyone know what would cause the image to be a bit jumpy on motion.. like not enough frames or something .. its running at 29.97 FPS
[04:29:44 CEST] <Prelude_Zzzzz> but when they move its like the frame is slightly trembling
[04:31:56 CEST] <pinPoint> image or video?
[04:34:20 CEST] <Prelude_Zzzzz> video
[04:34:34 CEST] <Prelude_Zzzzz> when they turn their heads and stuff.. there is like blur effect
[04:34:40 CEST] <Prelude_Zzzzz> like not enough frames or something
[04:34:55 CEST] <Prelude_Zzzzz> i am using 1 reference frame .. so generally when you use too many i would see that happen
[04:36:18 CEST] <pinPoint> anYc: thanks. nice work
[04:49:31 CEST] <pinPoint> sounds like an effect of either 60hz or 120hz
[04:49:55 CEST] <pinPoint> its like strobbing i see on my 60hz tv on some blurays... like not a fast responce time
[04:55:20 CEST] <Prelude_Zzzzz> i am using a 1080p monitor
[04:56:24 CEST] <pinPoint> not enough ms responce? that is my guess with strobbing
[05:09:25 CEST] <wyatt8740> pinpoint: I'm guessing that strobing is watching a film source where the frames of film have been exposed slightly differently/have aged, or where the projector strobing effect has been introduced to give a more cinematic experience
[05:09:45 CEST] <wyatt8740> or you're watching on a CRT
[05:10:40 CEST] <pinPoint> possibly
[05:10:42 CEST] <wyatt8740> Anyway, I have some old cartoons on DVD that display flicker because of (I believe) over/underexposure of frames. (Looney Tunes golden collection, the "Porky in Wackyland" short in particular)
[05:12:46 CEST] <wyatt8740> Do you think it'd be okay to take a 20 second clip or so of the episode to use as an example?
[05:14:30 CEST] <wyatt8740> (just the title cards)
[05:17:12 CEST] <wyatt8740> I suppose projecting with a single blade shutter might do it too
[05:19:14 CEST] <wyatt8740> I still use a CRT honestly. Because mine can do 720p and 1080i it's enough for me and my DVD's :)
[05:19:22 CEST] <wyatt8740> Though it does weigh 70 lbs
[05:20:11 CEST] <wyatt8740> http://i.imgur.com/x0NCQ7l.jpg
[05:20:40 CEST] <PovAddict> wow, 1080i CRT?
[05:20:50 CEST] <wyatt8740> yeah, it's from my local PBS station :)
[05:20:54 CEST] <wyatt8740> Sony PVM-20L5
[05:21:13 CEST] <wyatt8740> only accepts 1080i through analog ypbpr component or RGB though
[05:21:15 CEST] <wyatt8740> (or SDI)
[05:26:24 CEST] <pinPoint> i bet its still highend compared to todays tech
[05:34:13 CEST] <wyatt8740> I'd say so pinpoint
[05:34:22 CEST] <wyatt8740> especially because of the black levels
[05:36:43 CEST] <wyatt8740> I don't actually have a proper calibration device so I've been doing my calibration by eye based on SMPTE bars
[05:36:57 CEST] <wyatt8740> so that's the least pro part about it
[05:37:24 CEST] <wyatt8740> but yeah, the monitor was free!
[05:37:50 CEST] <wyatt8740> station was upgrading equipment to OLED's and since I was a volunteer I asked the engineer if they were getting rid of any CRT's and he let me have this
[05:37:59 CEST] <wyatt8740> since they're a nightmare to recycle
[05:45:32 CEST] <pinPoint> wyatt8740: you said you can code right?
[05:45:53 CEST] <wyatt8740> pinpoint: somewhat
[05:46:11 CEST] <wyatt8740> I would love to write a video filter for ffmpeg but have no idea how to go about that
[05:46:15 CEST] <wyatt8740> but small programs in C, yes
[05:46:38 CEST] <wyatt8740> as well as 6502 assembly and Z80 assembly but those aren't entirely useful
[06:11:14 CEST] <pinPoint> whois Claudio?
[06:27:16 CEST] <gilp> Hey, I got a question, I have a camera connected through a network that transmits using udp with h264 encoding, I am using FFmpeg's API to read the camera's frames, the camera sends about 25 fps, but I have an odd problem that once every second I get 3-4 frames with a delay of 100ms, the followup "missed" frames arrive immediately after the first delayed one (0-2ms), it causes the video to "freeze" for a bit every second, I can only assume it's either something
[07:10:03 CEST] <wyatt8740> pinpoint: why did you ask? (about coding)
[07:10:09 CEST] <wyatt8740> (and about claudio)
[07:10:27 CEST] <pinPoint> reading some github stuff on ffmpeg
[07:10:39 CEST] <pinPoint> just curious on coding
[07:11:31 CEST] <wyatt8740> I'm curious too. My only real contribution to ffmpeg was a feature request that someone else did for me.
[07:11:35 CEST] <wyatt8740> (asked for the hqx filter)
[07:12:11 CEST] <wyatt8740> (see here http://blog.pkh.me/p/19-butchering-hqx-scaling-filters.html and the ticket https://trac.ffmpeg.org/ticket/3404 )
[07:12:32 CEST] <pinPoint> i'm seriously contemplating learning C on the side just slowly on downtime days.
[07:12:39 CEST] <pinPoint> where I have 1-2hrs here and there
[07:13:04 CEST] <wyatt8740> Dennis Ritchie's book is still great
[07:13:06 CEST] <wyatt8740> (RIP)
[07:13:15 CEST] <pinPoint> He started it all
[07:13:35 CEST] <wyatt8740> I never got to meet him. Wish I could have. I know very little about his personality
[07:14:29 CEST] <wyatt8740> There are a lot of people I'd like to meet that'll probably be dead soon or are already dead :(
[07:14:34 CEST] <pinPoint> When Jobs passed everyone was buzzing about it. Ritchie passed and nobody even knew who He was. Unfortunately
[07:14:43 CEST] <wyatt8740> Jobs died the day after my birthday
[07:14:50 CEST] <pinPoint> eek
[07:14:52 CEST] <wyatt8740> (oct 5)
[07:14:57 CEST] <wyatt8740> (my bday's the 4th)
[07:15:09 CEST] <wyatt8740> oh, actually
[07:15:14 CEST] <wyatt8740> its the 12th now here
[07:15:21 CEST] <wyatt8740> its the fourth anniversary of his death
[07:15:25 CEST] <wyatt8740> (Ritchie's)
[07:15:40 CEST] <wyatt8740> or rather of the day we discovered he was dead.
[07:17:20 CEST] <pinPoint> wait they found Him later ?
[07:17:22 CEST] <gilp> Hi, is there an builtin way to create a back buffer in ffmpeg?
[07:17:26 CEST] <wyatt8740> He lived alone pinpoint
[07:17:32 CEST] <wyatt8740> he could have died on the 11th for all I know
[07:17:50 CEST] <wyatt8740> his exact time of death was never disclosed
[09:34:58 CEST] <DarthDepa> Hi guys! :)
[09:35:09 CEST] Action: DarthDepa pokes c_14 
[09:35:24 CEST] <DarthDepa> c_14: Finally, I got another error lol
[09:36:56 CEST] <DarthDepa> http://paste.ubuntu.com/12761908/
[09:37:53 CEST] <DarthDepa> I run it with "--enable-gpl --enable-libx264 --enable-libmp3lame --enable-nonfree --enable-libass --enable-libfreetype"
[09:40:11 CEST] <DarthDepa> I'm pasting the "config.log" file
[09:40:49 CEST] <c_14> That's a bug in gcc
[09:41:14 CEST] <DarthDepa> :O
[09:41:17 CEST] <c_14> What version of gcc are you running?
[09:41:18 CEST] <DarthDepa> c_14: Hi :)
[09:41:51 CEST] <DarthDepa> c_14: gcc (Raspbian 4.9.2-10) 4.9.2
[09:42:02 CEST] <DarthDepa> http://paste.ubuntu.com/12761924/
[09:42:55 CEST] <DarthDepa> The differences from last time are "--enable-libass --enable-libfreetype" options
[09:43:35 CEST] <c_14> What happens if you run make again?
[09:43:41 CEST] <DarthDepa> wait lol
[09:47:10 CEST] <DarthDepa> c_14: It is on "CC     libavcodec/h264qpel.o"
[09:47:25 CEST] <DarthDepa> It tooks a lot lol
[09:50:53 CEST] <DarthDepa> c_14: That fuc**** UMS it's making me crazy! lol
[09:53:06 CEST] <DarthDepa> c_14: Anyway it seems working because I got the error on "CC     libavcodec/h264qpel.o" and now it past that point
[09:54:05 CEST] <DarthDepa> Which was the problem?
[09:54:20 CEST] <DarthDepa> c_14: You are my Gandalf! lol
[09:54:27 CEST] <DarthDepa> c_14: thanks
[09:57:46 CEST] <DarthDepa> c_14: I will write you with the result :) Thanks
[11:14:21 CEST] <RazWelles> Hey, for screenshots I can number with %03d, but can I have it indicate timecodes instead?
[11:14:26 CEST] <RazWelles> What would be the code for that if so?
[12:45:18 CEST] <feliwir> hey, how to get the aspect ratio of the video stream? (preferably without AVFrame)
[12:45:36 CEST] <JEEB> depends on if the container contains the information
[12:45:59 CEST] <JEEB> I think some sort of decoding/parsing is required if it's only in the bit stream
[12:51:35 CEST] <ph8> Hi all, i'm trying transcode AVCi100 to H264 - does anyone know if this is possible with ffmpeg?
[12:52:47 CEST] <feliwir> JEEB, so i need to do:av_guess_sample_aspect_ratio ?
[13:01:47 CEST] <iive> ph8: H264 is known as AVC ...
[13:02:10 CEST] <iive> ph8: if ffplay can decode the source, ffmpeg should be able to transcode it.
[13:04:09 CEST] <furq> ph8: https://en.wikipedia.org/wiki/AVC-Intra#Third-party_support
[13:04:18 CEST] <furq> FFmpeg and Libav support decoding of both forms of AVC-Intra[20]
[13:34:54 CEST] <shALKE> Hi, I'm little new to ffmpeg, looking to record from a BlackMagic DeckLink card to ProRes 422 with same settings as the input signal. Profile 2. Can someone help me with the command line settings?
[15:28:25 CEST] <ph8> thanks furq - sadly i've got some 'raw' folders with CLIPINF (.CPIs) PLAYLIST (one .MPL) STREAM (.MTSes)
[15:28:29 CEST] <ph8> no idea how to input those to ffmpeg
[15:28:32 CEST] <ph8> can't find anything online
[15:35:14 CEST] <furq> ph8: presumably you just use the .mts
[15:36:49 CEST] <ph8> yeah
[15:36:53 CEST] <ph8> so my recording is split across 3 of those
[15:37:02 CEST] <ph8> about 5 of those in fact
[17:50:24 CEST] <Eduard> Hi, i am trying to capture from a DeckLink card in ProRes and I am getting no audio... any suggestions ?  C:\ffmpeg\bin\ffmpeg.exe -probesize 5000000 -f decklink -i "DeckLink SDI 4K at 15" -r 59.94 -c:v prores -profile:v 2 -c:a pcm_s24be -ar 44100  -pix_fmt yuv422p10le -threads 0 ProResTest.mov
[18:01:08 CEST] <Eduard> 304 bots here? :)
[18:59:51 CEST] <StephenS> is there a way to speed up transpose=1, or rotation metadata rotate tag removal in ffmpeg?
[19:00:15 CEST] <StephenS> or is there any other way to just remove rotate tag from metadata of video mp4 file, which is faster than a whole matrix transpose
[19:13:51 CEST] <StephenS> so actually I want to remove metadag or to transform/transpose video so it lose rotate: 90 info
[19:14:01 CEST] <StephenS> I do this ffmpeg -i in.mp4 -vf "transpose=1" -metadata:s:v:0 rotate=0 -strict -2 out.mp4
[19:14:12 CEST] <StephenS> however is there a better and faster way to fix this?
[19:14:20 CEST] <PovAddict> it seems like you could use "-vcodec copy" since changing metadata shouldn't need reencoding
[19:24:01 CEST] <StephenS> c_14 here?
[19:24:08 CEST] <StephenS> PovAddict ah
[19:24:16 CEST] <StephenS> I think something is wrong, I dont know how well you know android
[19:24:29 CEST] <StephenS> but by default portrait orientation adds rotate metatag to video: 90
[19:24:51 CEST] <StephenS> now I see correctly video in chrome, since chrome ignores rotate tag, but in other players,  like quicktime (firefox) etc, rotate tag is recognized and rotated
[19:24:52 CEST] <PovAddict> when filming with the android camera vertically?
[19:24:57 CEST] <StephenS> yes
[19:25:10 CEST] <StephenS> horizontally I get no rotate tag, and everything is well on web
[19:25:11 CEST] <PovAddict> why is it correct to ignore the tag? :/
[19:25:36 CEST] <StephenS> I dont know, ask chrome, but ignoring that rotate tag, my video is fine on chrome for portrait/vertically orientation
[19:25:49 CEST] <StephenS> I suspect that if I remove rotatetag it will fix it, however it doesnt
[19:26:05 CEST] <StephenS> so I had to transpose it
[19:26:17 CEST] <StephenS> but imagine if I have 300 video uploads/minute
[19:26:17 CEST] <PovAddict> maybe you have it backwards
[19:26:21 CEST] <StephenS> thats a lot of resources
[19:26:24 CEST] <StephenS> PovAddict ?
[19:26:37 CEST] <PovAddict> chrome pays attention to the tag and rotates it and looks fine, quicktime ignores the tag and looks bad
[19:27:09 CEST] <PovAddict> when a device adds a rotate=90 tag it usually means the video itself is horizontal, so it has to be rotated 90° to show in the correct vertical orientation
[19:27:21 CEST] <PovAddict> otherwise it would be quite an android bug...
[19:27:45 CEST] <StephenS> maybe you are right
[19:28:12 CEST] <StephenS> but anyway I need to remove that rotate tag, as I want to see correctly vertically recorded video
[19:28:17 CEST] <StephenS> and I cant with that rotate 90 tag
[19:28:30 CEST] <PovAddict> if I'm right, then to support players that ignore the tag, you have no option but to transpose (and remove the tag, otherwise it would be rotated twice by players that support it)
[19:28:45 CEST] <StephenS> you are right
[19:29:00 CEST] <StephenS> I googled this a bit, but there are no many topics about this
[19:29:13 CEST] <StephenS> maybe a few and not so many players either, those with dubsmash vine and ig
[19:29:19 CEST] <PovAddict> thing is, I think it's theoretically possible to efficiently rotate MPEG video
[19:29:22 CEST] <StephenS> but I heard that IG and Vine tranpose them on android
[19:29:28 CEST] <StephenS> isnt that resource heavy for weak phones?
[19:29:34 CEST] <StephenS> I mean using ffmpeg on android is resource suicide
[19:30:03 CEST] <PovAddict> they could be rotating the raw video before encoding it
[19:30:14 CEST] <PovAddict> I mean they have to encode it sooner or later or you won't get a .mp4 :P
[19:31:17 CEST] <StephenS> who, android it self, or apps?
[19:31:27 CEST] <PovAddict> I have no idea what android's video capture API is capable of
[19:32:13 CEST] <StephenS> first I thought that setOrientationHint() could have fixed this
[19:32:24 CEST] <StephenS> pre-encoding stuff
[19:32:27 CEST] <StephenS> but never tested it
[19:32:36 CEST] <StephenS> I was very doubtful that android even has this option
[19:34:54 CEST] <StephenS> btw PovAddict ffmpeg -i in.mp4 -vf "transpose=1" -metadata:s:v:0 rotate=0 -strict -2 out.mp4
[19:35:06 CEST] <StephenS> is not that slow I think, video of 20s is transposed in less than a 4s
[19:35:25 CEST] <PovAddict> transposing is super fast, the slow thing is decoding and re-encoding :P
[19:36:03 CEST] <StephenS> I'm not doing none of that?
[19:36:08 CEST] <PovAddict> you are
[19:36:08 CEST] <StephenS> any of that*
[19:36:19 CEST] <StephenS> so no way to avoid this?
[19:36:22 CEST] <PovAddict> decode -> transpose uncompressed images -> encode
[19:36:48 CEST] <StephenS> You mentioned -vcodec copy
[19:36:55 CEST] <PovAddict> to remove the tag, yes
[19:36:58 CEST] <StephenS> ffmpeg -i in.mp4 -vcodec copy -strict -2 out.mp4
[19:37:00 CEST] <PovAddict> but not to transpose the image itself
[19:37:00 CEST] <StephenS> that would work?
[19:37:40 CEST] <StephenS> well tag is not removed
[19:37:41 CEST] <StephenS> Metadata:
[19:37:41 CEST] <StephenS>       rotate          : 90
[19:37:48 CEST] <StephenS> after -vcodec copy its still there
[19:38:09 CEST] <PovAddict> does -metadata:s:v:0 work with -vcodec copy?
[19:39:04 CEST] <StephenS> maybe -metadata:s:v:0 rotate=0 ?
[19:39:42 CEST] <PovAddict> that :P
[19:40:03 CEST] <StephenS> ok -metadata:s:v:0 rotate=0 -strict -2 out.mp4
[19:40:20 CEST] <StephenS> worked, no metatag rotate, however video is still "wrongly" displayed in browser
[19:40:27 CEST] <StephenS> and speed of -metadata:s:v:0 rotate=0 -strict -2 and transpose is about the same
[19:40:43 CEST] <PovAddict> did you try in chrome?
[19:40:46 CEST] <StephenS> so I guess Ill use transpose, as it removed the tag and actually transposes/rotate video to "normally" displayed video in browsers
[19:41:04 CEST] <StephenS> PovAddict yes after removing rotate 90, display in chrome is screwed up too
[19:41:12 CEST] <PovAddict> there you go
[19:41:17 CEST] <StephenS> so you were right, chrome cares about rotate tag :)
[19:41:37 CEST] <PovAddict> so you need either the tag (and players that support it) or permanent transposing (which needs re-encoding)
[19:41:53 CEST] <StephenS> well as you can see, tag is useless as some players care and some dont
[19:41:56 CEST] <StephenS> so I need to transpose it
[19:42:05 CEST] <StephenS> now the only question is, will I do it in android or on my backend side
[19:42:45 CEST] <PovAddict> it *may* be possible to transpose the image in android before encoding it, so it won't be any slower, because you would still encode just once like now
[19:42:54 CEST] <PovAddict> but again I have no clue about Android video capture and encoding APIs
[19:43:16 CEST] <StephenS> PovAddict yeah but I still had to use ffmpeg, to get a thumbnail
[19:43:33 CEST] <StephenS> and I def dont want to do that on android side, as they can manipulate thumbnails (more experienced users/programmers) :)
[19:50:44 CEST] <PlanC> I'm kind of confused about whether I should use CBR (constant bitrate) or VBR (variable bitrate) for my MP3s
[19:50:58 CEST] <PlanC> CBR seems useful as I think more devices support it
[19:51:10 CEST] <PlanC> the downside is that the bitrate has to be a tad higher than the max bitrate otherwise the quality will drop
[19:51:12 CEST] <PovAddict> is VBR unsupported by any devices you care about?
[19:51:23 CEST] <PlanC> I'm not sure, that's the problem
[19:51:23 CEST] <PovAddict> VBR has existed for quite a while now...
[19:51:36 CEST] <PlanC> what about car stereos?
[19:51:42 CEST] <PlanC> they're usually pretty old fashioned?
[20:04:46 CEST] <StephenS> PovAddict btw that transpose gives me a file with lower/smaller size, how come?
[20:14:11 CEST] <llogan> StephenS: ffmpeg will automatically rotate and then strip the rotate metadata. if your build doesn't do that then it is old
[20:15:38 CEST] <StephenS> it doesnt do that
[20:15:50 CEST] <StephenS> but it min sdk is 3.0
[20:15:53 CEST] <StephenS> maybe because of that?
[20:16:20 CEST] <llogan> sdk?
[20:16:28 CEST] <PovAddict> does android include ffmpeg?
[20:16:34 CEST] <StephenS> no
[20:16:43 CEST] <StephenS> You need to build it separately
[20:16:49 CEST] <PovAddict> then why does the android sdk matter?
[20:17:03 CEST] <StephenS> maybe they have it in their API, the newest one?
[20:17:08 CEST] <StephenS> which I doubt though
[21:11:43 CEST] <ubitux> Hi everyone
[21:11:51 CEST] <ubitux> The FFmpeg project is conducting a survey on the project directions
[21:11:55 CEST] <StephenS> ?
[21:12:03 CEST] <ubitux> The survey is very quick to do, anonymous, and doesn't require any registration
[21:12:08 CEST] <ubitux> You can find it at https://fr.surveymonkey.com/r/QCP7JSS
[21:12:14 CEST] <ubitux> Please take a few minutes to participate if the project matters to you.
[21:12:19 CEST] <ubitux> This survey will end on 2015/11/14 and a public report will be made.
[21:12:23 CEST] <ubitux> Thanks
[21:14:15 CEST] <StephenS> cool
[21:16:05 CEST] <StephenS> done
[21:29:51 CEST] <xerox> done!
[21:52:36 CEST] <Admin_234234> hey guys.. on channel changes.. to increase channel change time on live tv.. what setting can i use to make sure the stream starts right when i change to the first segment ?
[21:52:42 CEST] <Admin_234234> i frame or something ?
[21:53:23 CEST] <PovAddict> you would need 100% i-frames to get immediate channel changes, and that would need a ridiculous amount of bandwidth
[21:53:42 CEST] <Admin_234234> ic... what setting would i use to increase it every 1 second or something
[21:53:44 CEST] <Admin_234234> or every 30 frames
[22:01:44 CEST] <benbro1> when I'm cutting mp4 video with "-ss ... -t ... -c:v copy -c:a copy"  the first part is corrupted and it takes a second to show a nice video
[22:01:57 CEST] <benbro1> can I cut in the nearest keyframe or similar?
[22:02:13 CEST] <PovAddict> benbro1: I don't know if it has improved, but last time I tried, I had to do that "manually"
[22:02:41 CEST] <PovAddict> there's some ffmpeg command to get the list of keyframes, then manually find the one nearest to my cutpoint, then use it in the -ss
[22:03:31 CEST] <benbro1> ffprobe -show_frames -select_streams v -print_format json=c=1 input.mp4
[22:03:35 CEST] <benbro1> this? ^^
[22:03:41 CEST] <PovAddict> -show_frames sounds familiar, yeah :)
[22:05:01 CEST] <benbro1> trying
[22:08:16 CEST] <StephenS> Admin_234234 are you in twitch team? :O
[22:08:26 CEST] <benbro1> PovAddict: doesn't seem to help
[22:08:29 CEST] <benbro1> trying to update ffmpeg
[22:09:49 CEST] <benbro1> still corrupted
[22:40:43 CEST] <Nickwiz> Burning various information onto video for testing purposes using drawtext, but having some issues. E.g. burning text=%{pict_type} %{frame_num} etc., and then playing back result file with ffplay does not show same pict_type on same frame.
[22:41:11 CEST] <Nickwiz> Is it because it burns input picture type and output is changed?
[22:50:59 CEST] <xerox> I had no idea ffprobe existed, that json output is sweet :)
[22:51:12 CEST] <PovAddict> I had no idea ffprobe had json output :)
[22:59:14 CEST] <Nickwiz> benbro1: What is your exact line? Note that: ffmpeg -ss 00:00:10 -i input.mp4 -t 00:00:10 ... differ from e.g. : ffmpeg -i input.mp4 -ss 00:00:10 -t 00:00:10 ... etc
[23:02:29 CEST] <Nickwiz> Do you use ffmpeg -ss ... -i input.mp4 -t ... -c:v copy -c:a copy out.mp4?
[23:19:08 CEST] <benbro1> Nickwiz: I tried both
[23:19:23 CEST] <benbro1> -ss at the beginning gives me a corrupted frame
[23:19:34 CEST] <benbro1> -ss after -i gives me black frame
[23:19:51 CEST] <benbro1> after a second both get fixed
[23:20:18 CEST] <benbro1> Nickwiz: I'm encoding with gstreamer x264enc element with the default settings. maybe I need to improve something there
[23:20:27 CEST] <benbro1> before trying to cut with ffmpeg
[23:26:49 CEST] <Ionic> I've got a weird problem here. According to a report, enabling VTB only (no VDA) on 10.11 leads to this bug: `https://github.com/mpv-player/mpv/issues/2299
[23:27:01 CEST] <hassoon> gentlemen i would like to know the best command line options (encoders, etc) for recording a browser-based 3D game
[23:27:21 CEST] <hassoon> given that i have a core i3 4005U cpu
[23:27:21 CEST] <Ionic> Enabling both seems to make it work - but I was told VDA was removed in 10.11? How can enabling it even compile?
[23:27:24 CEST] <wolfman2000> Afternoon. Reminder needed. When configuring ffmpeg, if an option says [no] in --help, does that generally mean that option is NOT enabled? I'm confused by seeing a --disable-static with [no] and an --enable-shared with [no]
[23:27:46 CEST] <Ionic> wolfman2000: by default, yes. Unless you enable the feature.
[23:30:51 CEST] <BasisBit> we just changed our game from ffmpeg from 2011 to version 2.8, adapted our headers and some minor changes in our glue-code. now we have the problem that videos played with ffmpeg are a lot behind that the seek position reports. any idea what main functions changed there?
[23:31:14 CEST] <BasisBit> *what
[23:38:25 CEST] <benbro1> does "crf" in h264 define the max bitrate?
[23:45:46 CEST] <JEEB> no
[23:45:50 CEST] <JEEB> it defines the rate factor
[23:45:56 CEST] <JEEB> it's another base rate control mode
[23:46:13 CEST] <JEEB> just like just setting a bit rate sets the average bit rate rate control
[23:46:32 CEST] <JEEB> you then use VBV (maxrate+bufsize) to limit the rate control to a specific maximum bit rate over a buffer
[23:47:00 CEST] <PovAddict> in my experience crf gives me a more intuitive easy knob for quality vs size
[23:47:20 CEST] <JEEB> yes, the main rate control modes should be picked according to your needs
[23:47:49 CEST] <JEEB> if you need a specific file size (ABR) - bit rate (and hopefully 2pass), if you just need around some quality level, then crf
[23:48:08 CEST] <JEEB> and in both cases VBV is something you can add to limit the maximum bit rate over bufsize
[23:48:14 CEST] <PovAddict> specific bitrate is mostly useful for streaming
[23:48:26 CEST] <JEEB> not really
[23:48:31 CEST] <JEEB> streaming needs VBV
[23:49:03 CEST] <JEEB> as long as VBV is set accordingly it doesn't really matter which rate control mode you use, and ABR can really be worse than CRF in live streaming
[23:49:15 CEST] <PovAddict> what does VBV stand for?
[23:49:37 CEST] <Makalak> Hi, long story short, i'll need to re-encode mkv to mp4 videos (1080p roughly 1.5gb), im considering getting a dedicated server for this, but would like your opinion on specs i should look for, for decent encoding speeds
[23:49:39 CEST] <JEEB> https://en.wikipedia.org/wiki/Video_buffering_verifier
[23:49:45 CEST] <JEEB> basically a buffering model :P
[23:50:00 CEST] <JEEB> you have a maxrate and a bufsize and some other variables that in 99% of all cases you don't need to touch
[23:50:07 CEST] <PovAddict> Makalak: 1.5GB is the total? or is that per file?
[23:50:32 CEST] <Makalak> PovAddict, per file, at this stage, i can't tell how many, but i expect alot
[23:50:38 CEST] <PovAddict> ah okay
[23:50:49 CEST] <JEEB> basically everything that goes through a limited pipe of one or other description requires VBV
[23:51:10 CEST] <JEEB> be it physical medium (like blu-ray with maxrate/bufsize of 40mbps)
[23:51:15 CEST] <JEEB> or networking
[23:51:48 CEST] <PovAddict> so VBV simulates the playback side of buffering, and when it's exceeding limits, it tells the encoder to reduce bitrate?
[23:52:26 CEST] <JEEB> something like that, yes. it's a part of the spec and is how you handle buffering and limiting rate control in AVC
[23:52:30 CEST] <JEEB> x264's VBV is really good
[23:52:46 CEST] <PovAddict> wikipedia says "In the H.264 and VC-1 standards, the VBV is replaced with generalized version called Hypothetical Reference Decoder (HRD)."
[23:52:51 CEST] <PovAddict> is that conceptually still the same thing?
[23:53:01 CEST] <JEEB> pretty much
[23:53:13 CEST] <JEEB> also not sure how true since x264 still calls it VBV in the options
[23:53:26 CEST] <JEEB> hrd IIRC had some extra signaling too
[23:53:32 CEST] <JEEB> but that usually isn't required
[23:55:06 CEST] <benbro1> JEEB: interesting. thanks
[23:55:31 CEST] <benbro1> JEEB: I was using CBR which gave me a huge file size. trying with CRF now
[23:56:35 CEST] <JEEB> to limit maximum rate you use VBV, that works as long as you are not using the constant quantizer rate control mode (which you never should be using :P )
[00:00:00 CEST] --- Tue Oct 13 2015

More information about the Ffmpeg-devel-irc mailing list