[Ffmpeg-devel-irc] ffmpeg.log.20160226

burek burek021 at gmail.com
Sat Feb 27 02:05:01 CET 2016


[00:00:02 CET] <julius> this one can do 30fps, but the picture isnt that great
[00:00:24 CET] <Interrogator> ok i will try that
[00:00:26 CET] <julius> how about the c310 - ever used that one?
[00:00:33 CET] <julius> its a logitech
[00:03:18 CET] <jkqxz> I could believe that I recognise it, but I don't remember it specifically.  Sorry.
[00:04:01 CET] <TD-Linux> the ps3 eye is $7 on amazon and can hit 120fps
[00:04:23 CET] <TD-Linux> though it's designed for computer vision, not visual quality. it gives extremely stable frame rates at the expense of noise
[00:06:18 CET] <julius> maybe i should get the 920
[00:10:09 CET] <Interrogator> [tls @ 03e20a60] The TLS connection was non-properly terminated.
[00:10:09 CET] <Interrogator> https://www.youtube.com/watch?v=jkvbfirXJmU: Input/output error
[00:10:34 CET] <Interrogator> it s what im obtaining as report
[00:13:54 CET] <firewated> what are you trying to do?
[00:15:51 CET] <firewated> i got that error message when inputting the youtube url as an input to ffmpeg
[00:16:32 CET] <firewated> i was suggesting you use youtube-dl to get the direct link to the audio and video files using the "-g" option, then feeding as an input to ffmpeg
[00:17:16 CET] <julius> TD-Linux, whats the "ps3 eye" ?
[00:17:29 CET] <TD-Linux> julius, search on google or amazon
[00:18:17 CET] <TD-Linux> wow it's now $5 in my region
[00:18:18 CET] <TD-Linux> buy 10
[00:19:18 CET] <J_Darnley> The eye toy was my favourite webcam
[00:19:30 CET] <J_Darnley> at least until MS killed unsigned drivers
[00:22:43 CET] <julius> TD-Linux, hey, thank you
[00:22:57 CET] <julius> that actually looks like a perfect solution
[00:23:41 CET] <julius> i can oversee ms mistakes, i have forgiven them a long time ago
[01:15:06 CET] <maziar> what is the best way to convert mp4 ?
[01:15:13 CET] <maziar> is any one here ?
[01:20:08 CET] <x86iac> to ?   use ffmpeg to avi ?
[01:21:41 CET] <maziar> x86iac to make multiple quality from 1080.mp4 to 720.mp4 and 480.mp4
[01:23:24 CET] <x86iac> answer is still ffmpeg
[01:24:44 CET] <x86iac> you want to see man page -s
[01:27:33 CET] <J_Darnley> or this http://trac.ffmpeg.org/wiki/Encode/H.264
[14:11:13 CET] <mrec> can yadif be used without the graph functions?
[14:13:07 CET] <mrec> the stream detection functions are just extremely slow so I'm not using those
[14:13:23 CET] <mrec> so basically at the moment I only use the decoder and do the rest myself..
[14:13:39 CET] <mrec> back to filters it seems that the ffmpeg streamdetection functions should be used again?
[14:13:42 CET] <mrec> all a bit confusing
[14:14:33 CET] <J_Darnley> What "graph functions"?
[14:14:44 CET] <J_Darnley> -vf yadif is all you needto use it
[14:15:10 CET] <mrec> I'm trying to write a player myself
[14:15:20 CET] <J_Darnley> oh API use
[14:15:41 CET] <mrec> the API is quite dirty..
[14:15:42 CET] <J_Darnley> you don't want to use the "magnificent" libavfilter API?
[14:15:59 CET] <mrec> yes, because it doesn't work well it seems
[14:16:07 CET] <J_Darnley> Then you will have to cut the yadif code out
[14:16:28 CET] <Mavrik> Huh, what exactly doesn't work on the filtergraph api?
[14:16:46 CET] <mrec> with the "reimplementation" of certain things I can change channels within 1 sec, by using the API well it's messy
[14:17:02 CET] <mrec> change channels = restart another stream and get a visible picture
[14:17:21 CET] <J_Darnley> The filter rests on top of the internal API providd by libavfilter
[14:17:45 CET] <J_Darnley> Mavrik: lots
[14:17:46 CET] <Mavrik> mrec, what's messy?
[14:17:53 CET] <Mavrik> J_Darnley, I mean it's not pretty
[14:17:58 CET] <Mavrik> J_Darnley, but it certanly does work.
[14:18:05 CET] <mrec> more or less the whole libav API
[14:18:10 CET] <J_Darnley> But no one undertsands how it works.
[14:18:17 CET] <Mavrik> J_Darnley, ?
[14:18:30 CET] <mrec> I tested several "ffmpeg" libraries for android and none of them work for playing mpeg-ts
[14:18:46 CET] <J_Darnley> I'm not going to repeat my arguments from a couple of years ago.
[14:18:58 CET] <mrec> I have done some implementation by using libavcodec a year ago and that works smooth even on android
[14:19:19 CET] <Mavrik> J_Darnley, well I guess you had some strong ones.
[14:19:46 CET] <Mavrik> (I prefer to use libav API than deal with having to maintain filter code manually due to copypasting it out.)
[14:20:07 CET] <Mavrik> mrec, well... ok :)
[14:20:17 CET] <Mavrik> If you have anything specific to ask we can help I guess.
[14:21:30 CET] <mrec> I'm playing from a live source (the libav api might be ok for filestreams)
[14:21:45 CET] <mrec> the filter API I mean
[14:22:04 CET] <Mavrik> O.o
[14:22:31 CET] <Mavrik> That's... not connected at all.
[14:22:53 CET] <Mavrik> Can you be specific about what the problems you have are?
[14:23:41 CET] <mrec> how to use yadif without the graph api
[14:24:07 CET] <mrec> guess I just have to spend some more time with it to come up with "better" questions
[14:24:27 CET] <Mavrik> The answer is: you shouldn't. It's not split.
[15:23:56 CET] <mrec> AVFormat->format = AV_PIX_FMT_YUV420P ?
[15:24:07 CET] <mrec> (for example)
[15:38:50 CET] <J_Darnley> sorry, is that a question?
[15:55:15 CET] <EmleyMoor> Is there something I can do with ffmpeg to make my videos upload to YouTube more readily?
[15:56:33 CET] <J_Darnley> What problem are you having?
[15:57:35 CET] <EmleyMoor> J_Darnley: Just that YouTube is occasionally slow to process them and it recommends I make them into a streamable format first - pointing me to this page: https://support.google.com/youtube/answer/1722171?hl=en-GB
[15:58:38 CET] <J_Darnley> What?  This part "moov atom at the front of the file (Fast Start)"?
[15:58:46 CET] <J_Darnley> -movflags +faststart
[15:58:59 CET] <EmleyMoor> It isn't telling me how I'm non-compliant.
[15:59:26 CET] <EmleyMoor> I will try that with my next upload though
[15:59:38 CET] <J_Darnley> You haven't told us anything either?
[15:59:45 CET] <J_Darnley> What do you have now?
[16:00:12 CET] Action: J_Darnley has lost the ability to write correct sentences
[16:01:01 CET] <EmleyMoor> Er... I told you the whole story as it is told to me by YouTube... I do know the codecs and frame rate are not the problem, but that's it.
[16:17:20 CET] <BtbN> just don't use mp4
[16:18:11 CET] <BtbN> and youtube will allways transcode your video, so there is no point in localy transcoding it again from what you already have.
[16:18:20 CET] <BtbN> Just remux it to mkv or at least move the moov atom.
[16:57:21 CET] <mrec> J_Darnley: no already the answer heh
[17:13:54 CET] <m3gab0y> hi guys, any suggestions on how to do 2-pass transcoding for HLS?
[17:14:54 CET] <J_Darnley> Impossible if you expect to stream
[17:15:06 CET] <J_Darnley> otherwise it is no different to usual 2-pass I guess
[17:17:44 CET] <m3gab0y> I need it for streaming :) can't get anything usable at low bitrate
[17:18:50 CET] <J_Darnley> 2-pass isn't a magic bullet that will 4k look perfect at 1Mbit
[17:20:00 CET] <J_Darnley> perhaps you should explain what "usable at low bitrate" means
[17:20:21 CET] <m3gab0y> I'm quite familiar with that- I just want to get something usable at 500 kbps - here is a good example of pushing h264 to the limits http://www.progettosinergia.com/flashvideo/advancedpostprocessing.html
[17:23:26 CET] <m3gab0y> any good recommendation of getting out the best of ffmpeg at 500 kbps is more than welcome :-)
[17:24:40 CET] <J_Darnley> use low resolution
[17:24:45 CET] <J_Darnley> remove noise
[17:24:52 CET] <J_Darnley> use slow settings
[17:26:05 CET] <m3gab0y> any particular example setting you got in mind
[17:26:05 CET] <J_Darnley> the second is difficult in ffmpeg, it lacks the best denoisers
[17:26:15 CET] <J_Darnley> -preset veryslow
[17:26:36 CET] <m3gab0y> I'm using the git-build, so it should be very recent version
[17:30:44 CET] <EmleyMoor> BtbN: Yes, but it implies strongly it won't take as long in some set of circumstances.
[17:37:01 CET] <BtbN> you won't get any usefull quality out of 500kbps, unless you are happy with 240p
[17:50:59 CET] <yann|work> anyone with experience with the AVHWAccel around ?
[18:00:30 CET] <jkqxz> yann|work:  Just ask your question.
[18:04:52 CET] <yann|work> I'm trying to understand how we're supposed to use the hwaccel code in libavcodec, but can't find much code on it
[18:05:27 CET] <yann|work> looks like the closest to a doc would be ffmpeg*.c
[18:06:08 CET] <jkqxz> Yeah, the canonical example is ffmpeg.c + ffmpeg_$HWACCEL.c.
[18:43:27 CET] <m3gab0y> @J_Darnley Thanks for the suggestions! Got something decent using denoise and deblock filters! @BtbN It's 400x320 which is perfectly fine for the target devices that it's gonna be used on, see for yourself: http://test8:test8@188.166.34.164/test
[19:35:50 CET] <Burlington> Hey folks.  I am trying to stream an mp4 to an hdmi output device.   If I use the output format "alsa", I am able to get audio to stream to the hdmi device, but no video.  Any idea what output format to use to stream video to hdmi?
[19:38:11 CET] <Burlington> http://pastebin.com/jGCC5yjU  This works well to send the audio, but after a few hours of putzing around, I still can't sort out how to send the video to this output device.
[19:42:15 CET] <relaxed> Burlington: use mpv
[19:42:29 CET] <debianuser> Burlington: It's not up to ffmpeg. It's up to xorg and your video player. :) HDMI is just another way to attach a display. You can't "send" video to a display, but you can show it on the screen. Expand your screen to that display with your regular desktop environment settings (or maybe "nvidia-settings", if you use official binary driver), then just move video player window to that display. :)
[19:43:50 CET] <debianuser> mpv, mplayer, vlc, smplayer... some gnome/kde players... any of them should work.
[19:45:51 CET] <hexploit> Im trying to concat two mp4 for files using concat demux. One of the mp4 files does not have an audio track (stripped using -an) while the other does. The end result of concatenation is a file that does not have an audio track. Relevant outputs are here: http://pastebin.com/TQAwB4Xn . Am I missing something?
[19:46:37 CET] <relaxed> hexploit: the file you concat need to match in regards to video/audio streams
[19:47:46 CET] <hexploit> relaxed: I tried adding a blank sound stream to the first mp4. In that case there is an audio stream but still no sound
[19:50:42 CET] <relaxed> dd.mp4 lacks an aac audio stream
[19:51:38 CET] <Burlington> @relaxed Thank you.   I did try that, but then I receive this as an output:  http://pastebin.com/dZD0xrs0
[19:52:22 CET] <J_Darnley> mpv is another piece of software, not an output device
[19:52:35 CET] <relaxed> Burlington: mpv is a serperate program for playing video files
[19:53:41 CET] <hexploit> relaxed: for that I tried creating another file using ffmpeg -f lavfi -i aevalsrc=0 -i dd.mp4 -vcodec copy -acodec aac -map 0:0 -map 1:0 -shortest -strict experimental -y ddd.mp4
[19:53:42 CET] <relaxed> separate*
[19:53:55 CET] <hexploit> and tried concatenating that
[19:54:01 CET] <Burlington> @debianuser  Thank you.  I am trying to understand this.  I have a secondary monitor connected via hdmi.   Ultimately, I am trying reciv
[19:54:23 CET] <Burlington> receive a video network stream and have it output to a clean hdmi line...
[19:54:58 CET] <hexploit> in that case there was an audio stream in the final output but still no sound
[19:55:44 CET] <relaxed> Burlington: with ffmpeg you're using the wrong tool for the job. Either use mpv, https://mpv.io/ , or vlc (which has a gui and might be easier for you)
[19:56:47 CET] <Burlington> @relaxed Thank you!  I've used ffmpeg for years now and I love it.   perhaps, you are right that VLC is a better tool for what I am trying to accomplish.   This is all CLI.
[19:57:37 CET] <relaxed> mpv is the best video player, and also is cli
[19:58:02 CET] <relaxed> ffmpeg is a transcoder
[20:04:41 CET] <relaxed> hexploit: from the pastebin dd.mp4 clearly doesn't have an audio stream
[20:05:28 CET] <hexploit> yeah it doesnt. I agree. Thats why I created a separate file with a blank audio stream
[20:06:48 CET] <relaxed> see if this works, MP4Box -cat 1.mp4 -cat 2.mp4 -new combined.mp4
[20:09:07 CET] <Burlington> @relaxed do you have thoughts on ffplay?   could that do the job?
[20:10:13 CET] <hexploit> will look into it. thanks
[20:10:50 CET] <relaxed> Burlington: no, ffplay is more for testing than anything
[20:30:38 CET] <Skull0inc> hello
[20:32:45 CET] <Skull0inc> just wondering if anyone knew if it would be possible to emulate DVR saving from an rtsp stream using ffmpeg? By that I mean to save a single stream to a fixed output size and constantly overwrite fifo format of that file.
[20:34:32 CET] <ChocolateArmpits> Skull0inc: look into segment format
[20:34:44 CET] <kepstin> Skull0inc: could do it with the segment muxer and an mpeg-ts output
[20:34:51 CET] <ChocolateArmpits> hls is based on that and it supports such behavior
[20:43:09 CET] <Skull0inc> hmm, ok.
[20:46:45 CET] <mrec> I wonder did anyone use libavcodec on android for playing back mpeg2 videos?
[20:46:55 CET] <mrec> I wonder if anyone achieved the 50fps
[20:47:53 CET] <mrec> I'm currently playing the video at 25fps (just using the normal yadif 25fps deinterlacer)
[20:48:12 CET] <Mavrik> yadif is incredibly CPU expensive
[20:48:32 CET] <Mavrik> Doing playback with SW decoder and yadif on a mobile phone at 50fps is probably going to work only on a few really fast devices.
[20:49:03 CET] <mrec> I'm sure that won't work easily yes
[20:49:21 CET] <mrec> do you have any experience with mpeg2 playback on mobile devices?
[20:49:42 CET] <mrec> I wonder if there's any way
[20:50:21 CET] <mrec> I'm not only targetting the mobile devices there are quite a few android media players out there
[20:52:52 CET] <Mavrik> Well, first I'd thrmf
[20:52:55 CET] <Mavrik> eh, sorry.
[20:53:05 CET] <Mavrik> First I'd check if the device HW decoder supports MPEG-2 and use that.
[20:53:13 CET] <Mavrik> Then fallback to SW decoding on as many cores as possible.
[20:53:22 CET] <Mavrik> If possible render to OGL surface.
[20:57:55 CET] <TD-Linux> mrec, on android I can play back 1080p VP9 in software, so I really hope you can achieve mpeg2 playback in software :)
[20:59:23 CET] <Mavrik> on top 10% of devices only?
[21:04:12 CET] <mrec> TD-Linux: mpeg2 playback is no problem but I'm concerned about smooth 50fps
[21:04:27 CET] <mrec> that also requires deinterlacing of course
[21:05:39 CET] <mrec> deinterlacing is just an option anyway I'm using the GPU for displaying the YUV frames onto the screen
[21:06:09 CET] <mrec> I figured out how to use the filter graph stuff it's not so difficult (I just expected it to be much more difficult ^^)
[21:07:36 CET] <GreaseMonkey> if you can do 1080p vp9 you can probably do 50fps mpeg2... as for deinterlacing you can probably do that in a shader
[21:10:05 CET] <kepstin> just using anything simpler than yadif would bee a good start, yeah
[21:10:47 CET] <kepstin> (ideally, you'd deinterlace the video before encoding, to make the stream smaller and easier to decode, of course...)
[21:11:07 CET] <mrec> I'm playing back live source (DVB)
[21:38:37 CET] <kasd11> heyho, can i do something like 4 point distortion with ffmpeg filters? googling only gave me an imagemagick example but i need to do it realtime. this is what i am talking about http://silveiraneto.net/2014/12/07/imagemagick-four-point-perspective-distortion-in-a-video/
[21:39:48 CET] <kasd11> i should have searched for "perspective" :) this seems to be it https://ffmpeg.org/ffmpeg-filters.html#perspective
[22:10:49 CET] <antiPoP> hi
[22:11:46 CET] <antiPoP> This command: "ffmpeg -i $videofile -c:v libx264 -preset ultrafast $new_video" only converts the video to x264 without changing resolution and and copies the audio, right?
[22:13:16 CET] <kepstin> antiPoP: unless you add -c:a copy it will re-encode the audio (to a codec selected automatically based on output format)
[22:13:30 CET] <kasd11> antiPoP, nope, by default it will convert the audio to vorbis
[22:13:33 CET] <kasd11> ah
[22:14:00 CET] <antiPoP> so it will convert to ogg vorvis then?
[22:14:09 CET] <antiPoP> wchi bitrate
[22:14:10 CET] <kasd11> trust him, not me
[22:14:14 CET] <kepstin> antiPoP: it depends on the output format. mp4 defaults to aac, for example.
[22:14:21 CET] <kepstin> if you want it to copy, use -c:a copy
[22:14:24 CET] <antiPoP> (I'm new to ffmpeg and I just found this on the code)
[22:14:55 CET] <antiPoP> kepstin, so in te case of x264 is vorbis, right?
[22:15:08 CET] <antiPoP> shouldn't be mp3?
[22:15:14 CET] <kasd11> x264 is the codec, not the output format (=container)
[22:15:15 CET] <kepstin> antiPoP: it depends on the output file format
[22:15:20 CET] <kasd11> that is mp4, mkv, avi etc
[22:16:17 CET] <antiPoP> it's mp4
[22:18:25 CET] <GreaseMonkey> x264 has nothing to do with audio
[22:19:02 CET] <GreaseMonkey> i think mkv typically uses ogg vorbis, and mp4 typically uses aac
[22:19:14 CET] <GreaseMonkey> mp4 also typically sucks horrendously
[22:19:23 CET] <antiPoP> https://trac.ffmpeg.org/wiki/Encode/H.264 I can't find any info here
[22:19:56 CET] <antiPoP> GreaseMonkey, well, it's web video and seems well supported by the player...
[22:19:57 CET] <kepstin> antiPoP: that's because h264 is a video codec; of course there wouldn't be anything about audio on that page.
[22:20:07 CET] <kasd11> please read up on the basics of video formats, codecs, containers and so on. otherwise this is all super confusing ;)
[22:20:08 CET] <kasd11> take care
[22:20:11 CET] <GreaseMonkey> (you can work around the moov atom nightmare but it tends to do buffer e.g. 16 video frames, then e.g. 16 audio frames)
[22:20:33 CET] <antiPoP> well, tehre is a mention to copy audio, but it doe snot says with which audio format is rencoded
[22:20:59 CET] <GreaseMonkey> antiPoP: to be blunt i'd seriously consider even .flv instead of .mp4, if you want streamable .mp4 you need a special option to drop the moov atom in early
[22:21:52 CET] <GreaseMonkey> although .webm is probably a better option unless you need to livestream (x264 encodes stuff fast, libvpx does NOT)
[22:22:05 CET] <kepstin> antiPoP: that's because the automatic selection depends on many factors. if you want a specific codec, you should specify one.
[22:22:09 CET] <GreaseMonkey> as far as i care mp4 is NOT a streaming format
[22:22:33 CET] <GreaseMonkey> for flv: -f flv -vcodec libx264 -acodec libmp3lame
[22:23:25 CET] <GreaseMonkey> for webm: -f webm -vcodec libvpx -acodec libvorbis (and then you usually change the quality setting as it usually produces a nasty image at the defaults)
[22:24:29 CET] <antiPoP> well, I'm using http://videojs.com/ as player
[22:24:35 CET] <GreaseMonkey> webm
[22:24:49 CET] <GreaseMonkey> really, just use webm
[22:25:16 CET] <antiPoP> what I want is to be able to have multiple resolutions in the player
[22:25:30 CET] <antiPoP> what the current code does not do
[22:25:57 CET] <GreaseMonkey> then you'll want to find some sort of irc channel for video.js
[22:26:05 CET] <GreaseMonkey> oh and one more thing
[22:26:13 CET] <antiPoP> I also have read about making a container with multiple resolutions so the player chooses automatically the stream...
[22:26:22 CET] <GreaseMonkey> apparently, "-movflags faststart" is what you need to make a streamable .mp4
[22:26:47 CET] <GreaseMonkey> if you have a container with multiple resolutions it's a waste of bandwidth, you'll want multiple files instead
[22:27:25 CET] <derekprestegard> hey guys - Im trying to do segment encoding (e.g. take one video and process many chunks of it in parallel using many machines and then re-assemble the results). It works fine for a relatively small number of segments like 18x 5 min chunks for a 90 min movie but when I try to do 90x 1 min chunks I end up with an audio desync. Does this sound familiar to anyone?
[22:27:49 CET] <antiPoP> GreaseMonkey, ok thanks, ill check webm
[22:28:11 CET] <antiPoP> and the movflags option
[22:28:18 CET] <TD-Linux> derekprestegard, yes, my first recommendation is to *not* segment the audio when encoding
[22:28:26 CET] <J_Darnley> GreaseMonkey: for an extremely loose definition of streaming.
[22:28:41 CET] <derekprestegard> TD-Linux: indeed, we handle audio separately as a parallel process on a single machine
[22:28:58 CET] <TD-Linux> and you still get desyncs? sounds like a muxer bug
[22:29:08 CET] <kepstin> derekprestegard: all constant-framerate content?
[22:29:15 CET] <derekprestegard> we have ffmpeg make mp4 files, then join them with mkvmerge
[22:29:16 CET] <derekprestegard> kepstin: yes sir
[22:29:26 CET] <derekprestegard> then ifnally back to mp4 with faststart including audio
[22:29:44 CET] <derekprestegard> I am going to check frame counts to see if were introducing addional frames somewhere
[22:31:00 CET] <dystopia_> why do you go to mp4 to mkv to mp4
[22:31:14 CET] <dystopia_> why not just cat the mp4 files
[22:31:18 CET] <derekprestegard> just because mkvmerge was something that I knew could stitch mp4s together well :)
[22:31:26 CET] <dystopia_> use mp4box
[22:31:42 CET] <derekprestegard> would I have timestamp issues? I dont use -copyts when segmenting
[22:32:02 CET] <dystopia_> mp4box -fps frameratehere -cat file1.mp4 -cat file2.mp4 -cat file3.mp4 output.mp4
[22:32:05 CET] <dystopia_> for example
[22:32:16 CET] <derekprestegard> thats handy
[22:32:23 CET] Action: TD-Linux really hopes this isn't yet another "how long is the last frame"
[22:32:45 CET] <derekprestegard> do you think mkvmerge is introducing problems?
[22:33:41 CET] <dystopia_> probably not
[22:36:06 CET] <TD-Linux> you are converting timebases twice, lots of room for bugs
[22:45:17 CET] <derekprestegard> so our logic is -ss $startTime -i $input -to $chunkDuration
[22:45:47 CET] <derekprestegard> so if I want to do 1 min chunks Id do -ss 0 -i $input -to 60, then -ss 60 -i $input -to 60
[22:45:49 CET] <derekprestegard> right?
[22:46:13 CET] <furq> -t 60, not -to 60
[22:47:08 CET] <derekprestegard> really? even though were not using -copyts?
[22:47:21 CET] <furq> oh. maybe not then
[22:47:25 CET] <derekprestegard> :)
[23:10:17 CET] <antiPoP> is possible to only specify the vertical resolution (eg 240) so the the horizontal one is calculated automatically?
[23:10:48 CET] <kepstin> antiPoP: if you use the scale filter, yes; read its docs for details.
[23:11:09 CET] <antiPoP> kepstin, https://trac.ffmpeg.org/wiki/Scaling%20(resizing)%20with%20ffmpeg here?
[23:11:37 CET] <antiPoP> yes, thanks
[23:12:01 CET] <kepstin> antiPoP: i'd start with https://www.ffmpeg.org/ffmpeg-filters.html#scale-1 but the wiki might have some helpful examples
[23:12:19 CET] <SebastianThorn> Hello, im looking at this but i dont understand where the file of the first pass gets saved? https://wiki.archlinux.org/index.php/FFmpeg#Two-pass_x264_.28very_high-quality.29
[23:12:40 CET] <JEEB> why would it get saved?
[23:12:42 CET] <SebastianThorn> is it just an example that saved to /dev(null?
[23:12:58 CET] <kepstin> SebastianThorn: the video statistics from the first pass are stored in a text file in the current working directory
[23:13:07 CET] <SebastianThorn> ok, then i dont understand how it works
[23:13:12 CET] <kepstin> the video output isn't needed, so it's thrown away
[23:13:13 CET] <SebastianThorn> kepstin: ahh, ok
[23:13:36 CET] <JEEB> 1st pass is to get statistics of the video (but the video is still created if you really want it), second pass is where that information is then used
[23:13:40 CET] <SebastianThorn> i thought that the first pass created a file for the second pass to use
[23:13:53 CET] <JEEB> it does, but outside the usual output file name
[23:13:57 CET] <SebastianThorn> JEEB: ok, thanks verry much
[23:14:14 CET] <furq> SebastianThorn: "very high-quality" on that page is misleading, 2-pass is only useful if you want to hit a specific bitrate
[23:14:29 CET] <JEEB> aand yes, I was going to note that
[23:14:30 CET] <furq> otherwise 1-pass crf is better
[23:14:40 CET] <kepstin> (or specific filesize, which is the same thing as specific bitrate)
[23:15:57 CET] <SebastianThorn> i bought a blyray set of all the James Bond movies and thought i try to rip then to play on my rpi2 using openelec (kodi). I tried with makeMKV and handbrake, but it lags when i run them, so i thight i take a couple of beers and try something else :)
[23:16:41 CET] <furq> there shouldn't be much (if any) difference between handbrake and ffmpeg's output
[23:17:04 CET] <furq> they both use the same underlying libraries
[23:17:36 CET] <SebastianThorn> furq: i agree, but i wanna try it anyways, so i can autamate it when i find settings that works good for me
[23:18:02 CET] <SebastianThorn> and i might learn somehing new :)
[23:18:21 CET] <furq> well obviously ffmpeg is much better than handbrake, otherwise i'd be in #handbrake
[23:18:52 CET] <SebastianThorn> i tried in #handbrade aswell, and google, but learning this might be good :)
[00:00:00 CET] --- Sat Feb 27 2016


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