[Ffmpeg-devel-irc] ffmpeg.log.20141105

[burek]

[02:27] <danomite> I'm trying to copy an RTSP stream but getting an error: http://pastebin.com/kNFELARn
[02:35] <blippyp> danomite: doesn't look like it likes your audio track? I could easily be wrong though, try to re-encode just the audio to aac to ac3 or something and see what happens...
[04:01] <edman007> hrm, so git ffmpeg crashes trying to encode some stuff using aac.... do I just post a bug on trac? I got the debug backtrace
[10:23] Action: DelphiWorld ugh emilsedgh
[10:38] <d3m0n> I am using this as my webm encode: "ffmpeg -i desktop-src.avi -c:v libvpx -quality best -cpu-used 0 -qmin 0 -qmax 62 -minrate 1M -maxrate 1M -b:v 1M -c:a libvorbis -vf scale=1280:720 -threads 6 desktop.webm"
[10:38] <d3m0n> But it changes the color of my source
[10:38] <d3m0n> How can I preserve that
[10:57] <c_14> Can you pastebin the output from ffmpeg as well as upload a picture showing the color corruption?
[10:59] <d3m0n> Yea sure one second please
[11:06] <d3m0n> c_14: http://pastebin.com/2ahYsfv0 / http://i.imgur.com/1lUufEP.jpg?1
[11:07] <d3m0n> That banding is killing me too
[11:14] <c_14> Hmm
[11:16] <c_14> First of all, qmin and qmax shouldn't do anything because you're using constant bitrate. Have you tried increasing the bitrate?
[11:17] <d3m0n> Does minrate and maxrate take effect if using b:v also?
[11:17] <d3m0n> I figure 1M is pretty good
[11:17] <d3m0n> I can try 2M
[11:17] <d3m0n> And how about -quality best
[11:17] <d3m0n> Does it make a difference
[11:20] <d3m0n> Increasing -minrate 1.5m -maxrate 2m -b:v 3m seems to make quality worse
[11:26] <relaxed> d3m0n: It could be the color conversion. Try, `ffmpeg -i desktop-src.avi -t 10 -pix_fmt yuv420p -c:v ffvhuff output.avi` and see if it looks any better.
[11:33] <d3m0n> Is there a command I can use to make it near lossless and degrade from there
[11:34] <relaxed> ffvhuff is lossless, except for the color conversion done with -pix_fmt yuv420p
[11:35] <d3m0n> Yeah that kept my color! But I am hoping for webm D:
[11:35] <relaxed> Did you add -pix_fmt yuv420p?
[11:35] <d3m0n> I just used your full command
[11:37] <relaxed> oh, well then we can assume it's not the color conversion. Did you see https://trac.ffmpeg.org/wiki/Capture/Desktop and https://trac.ffmpeg.org/wiki/Encode/VP8 ?
[11:37] <d3m0n> Well, when I used your command it kept my original color.
[11:37] <d3m0n> ANd yeah I've been trying to use the examples from that wiki
[11:38] <d3m0n> This was my command I came up with from that command " ffmpeg -i desktop-src.avi -c:v libvpx -quality best -cpu-used 0 -qmin 0 -qmax 62 -minrate 1M -maxrate 1M -b:v 1M -c:a libvorbis -vf scale=1280:720 -threads 6 desktop.webm"
[11:38] <d3m0n> But as c_14 mention I removed the qmin/qmax
[11:39] <relaxed> right, omit those and try -crf
[11:40] <d3m0n> including b:v/maxrate/min?
[11:41] <relaxed> no, try -crf 10
[11:44] <d3m0n> encoding now
[11:46] <d3m0n> "ffmpeg -i desktop-src.abi -c:v libvps -crf 10 -c:a libvorbis -threars 6 desktop.webm" produced quite a poor quality
[11:46] <d3m0n> Looks like it kept the right color though, but I can see some shaded flickering
[11:48] <relaxed> -crf 5 -b:v 3M
[11:51] <d3m0n> Haha yea, this is driving me nut. The quality is still seems fairly poor. The banding on the colors is bad
[11:55] <d3m0n> Maybe I am just expecting more than I should
[12:35] <Vardan> hi all
[12:35] <Vardan> people I have problem wit compile my application which is using ffmpeg I got following error: libavcodec.a(tiff.o): undefined reference to symbol 'lzma_code@@XZ_5.0'
[12:36] <Vardan> I have linked m and z (-lz -lm)
[12:45] <iive> Vardan: it's liblzma
[12:45] <iive> so try adding -llzma
[12:53] <Vardan> cool thanks :)
[12:56] <Vardan> I'm trying to understand one thing, I'm using ffmpeg and linked ffmpeg libs, now as I understand g++ what that I also link ffmpeg related libs too, is it possible to say g++ to link all ffmpeg related libs?
[13:01] <iive> g++ is used for C++, ffmpeg and libs are C only. Ignoring that, gcc/g++ can be used to call the linker and do the linking.
[13:30] <hanDerPeder> hi, I'm having an issue with ffmpeg on android, some rtsp streams are very choppy
[13:31] <hanDerPeder> seems it's caused by androids bionic c library does not support pthread_cancel
[13:32] <hanDerPeder> in libavformat/udp.c it seems this is needed when circular buffers are used, which seem to be the case, but I'm not sure
[13:32] <hanDerPeder> can anyone point me in the right direction as to how to debug this?
[14:52] <jonand> hi, I fail to get nv12 conversion working. http://pastebin.com/sr5ZAVPb Any clue?
[14:53] <jonand> avconv -pix_fmts |grep nv12 lists the nv12 format as available for both in and out.
[14:55] <c_14> avconv is part of libav, see #libav for help or use ffmpeg from FFmpeg
[14:56] <jonand> c_14: okay, thanks, I wasn't aware of the difference. I'll give ffmpeg a go.
[14:56] <c_14> Be aware if you're under ubuntu and non-testing debian the standard ffmpeg binary/package is actually also libav.
[14:57] <c_14> What you can do is compile from source or use a static build.
[14:57] <ubitux> jonand: add -f rawvideo as input option
[15:00] <jonand> ubitux: that solved my problem, thanks!
[16:09] <avidal> relaxed: did you update the archive for ffmpeg-2.4.2-64bit-static.tar.xz?
[16:09] <avidal> i computed a sha1sum on it a few days ago but now they don't match
[16:29] <jooon> Hey
[16:29] <jooon> I need help making a video from images
[16:29] <jooon> I am doing this now
[16:29] <jooon> ffmpeg -framerate 1/5 -i img%03d.png -c:v libx264 -vf fps=25 -pix_fmt yuv420p out.mp4
[16:30] <jooon> and what happens is that the first image is shown for 2 seconds
[16:30] <jooon> then it flashes the next image and the video stops
[16:30] <jooon> What I want to happen is for it to show each image for 2 seconds in a movie
[16:30] <ibex1101> Hello I'm new to FFmpeg and I'm trying to create a point to point connection from one to another computer. The host is working with Debian and the client with Ubuntu. I've tried to connect with a normal UDP connection and it worked but with a delay of about 5 or 6 seconds. The client recieved the streaming with VLC but now I'm trying to decrease the delay. How I'm going to do this? I also tried it with rtp but I'm not really getting it working. Hope you can help
[16:30] <jooon> so if there are 2 images, the movie is 4 seconds long
[16:31] <jooon> Any help would be greatly appreciated
[16:32] <blippyp> joon: ffmpeg -i img%03d.png -c:v libx264 -r 0.5 -pix_fmt yuv420p out.mp4
[16:33] <jooon> Blippy! Thank you so much!!
[16:33] <jooon> You are awesome!
[16:34] <blippyp> no problem
[16:34] <jooon> does ffmpeg support animations
[16:34] <jooon> on these images?
[16:34] <blippyp> you can improve your quality by adding a -crf 17 to it
[16:34] <blippyp> what do you mean by that?
[16:34] <jooon> like to slide the image in from the left
[16:34] <jooon> or zoom in on an image
[16:35] <koptein> Schipper, ibex1101: http://www.irchelp.org/irchelp/irctutorial.html
[16:35] <jooon> *slowly zoom in
[16:35] <blippyp> yes look at the man pages: man ffmpeg-filters
[16:35] <jooon> sweet
[16:35] <jooon> Thanks again
[16:35] <blippyp> glad i could help
[16:36] <ibex1101> Hello I'm new to FFmpeg and I'm trying to create a point to point connection from one to another computer. The host is working with Debian and the client with Ubuntu. I've tried to connect with a normal UDP connection and it worked but with a delay of about 5 or 6 seconds. The client recieved the streaming with VLC but now I'm trying to decrease the delay. How I'm going to do this? I also tried it with rtp but I'm not really getting it working. Hope you can help
[16:41] <ibex1101> Hello is someone there?
[16:42] <blippyp> ibex1101: be patient anyone who can answer your question and has the time to will likely be glad to help you.
[18:56] <varikonniemi> hello, is there something that can be done to this: Warning: data is not aligned! This can lead to a speedloss ? it started after i added ,scale: to my command
[18:57] <varikonniemi> both the cropping resolutions and final resolutions are divisible by 16
[18:57] <JEEB> I don't think it's the resolution, but rather the fact that the memory isn't aligned to specific alignments that let people do certain things faster
[18:58] <JEEB> what kind of input are you using because on all systems nowadays what lavc and friends do internally is mostly allocated with memaligned malloc
[18:59] <varikonniemi> it had no errors with only cropping, adding scaling gave the warning
[18:59] <varikonniemi> its analog av in to x264 + aac audio
[19:02] <danomite> blippyp, thanks!
[19:04] <JEEB> varikonniemi, well you probably had the nonalignment all the time then, but only the video filters check it
[19:04] <JEEB> *check for it
[19:04] <JEEB> and analog av really sounds like it
[19:04] <JEEB> since not lavc or whatever would be allocating the memory in that case
[19:05] <varikonniemi> the crop filter did not say anything, so it must be only the scale filter that notices it?
[19:06] <JEEB> probably, or the crop filter introduces the lack of alignment by just moving pointers and some other structures around
[19:07] <varikonniemi> that sounds plausible
[19:11] <danomite> Is there an option to output to a different file every half hour?
[19:12] <c_14> look at the segment muxer
[19:13] <danomite> thanks
[19:30] <[twisti]> would it be ok to ask a generic video encoding question ? im encoding a bluray file, and im having trouble making an educated choice about bitrate/file size. i dont really know much about video encoding, does anyone know if there is some sort of primer or tutorial or guide about bitrates and image quality ?
[19:33] <JEEB> if you are using x264 it's all rather simple
[19:33] <JEEB> (because it provides the simplest tools to achieve certain things)
[19:33] <JEEB> it has a rate control mode called CRF that is the closest thing we have to "constant quality" right now
[19:34] <JEEB> and it has a simple-to-use preset system to set your preference between speed and more compression efficiency
[19:35] <[twisti]> im more asking about what they mean
[19:35] <JEEB> also I hope you mean your input is a blu-ray transport stream because if you are actually encoding something meant to go on a blu-ray you are much more limited (so in a way you just don't have any alternatives regarding what to do), and ffmpeg can't output you compliant files out of the box (unless you use raw H.264 streams)
[19:36] <[twisti]> no, no, its something i copied and pasted off a BD
[19:36] <JEEB> [twisti], and I'm asking if you are using x264 to encode, because then I could just give the steps to find the balance for a type of source you have on hand
[19:36] <[twisti]> my goal is to reduce file size ideally without losing quality (although i understand that any encoding will lead to SOME amount of quality loss)
[19:36] <JEEB> because there are no "written on the wall" bit rates
[19:36] <[twisti]> yes, im using x264
[19:36] <JEEB> ok
[19:37] <[twisti]> if it helps, im trying to encode a tv show, 43-ish minutes per episode
[19:37] <JEEB> now, first of all limit your encode to a few thousand frames at first of content that your source is mostly of (-t and -ss will probably be of use)
[19:37] <JEEB> then start with just -preset medium (this is the default) and -crf 23 (this is actually too)
[19:37] <JEEB> then encode it, and see if it looks good
[19:37] <JEEB> if it does, raise the crf value
[19:38] <JEEB> this will make the encoder use higher quantizers, and effectively make a smaller file (and theoretically, worse quality)
[19:38] <JEEB> if it looks bad, then you lower the value
[19:38] <JEEB> after a couple of tries you should have found the highest crf value that still looks good to you, while gives you good compression
[19:38] <[twisti]> im having trouble 'telling' the quality with 'just my eyes', i know that sounds dumb, but i just cant tell right away
[19:39] <JEEB> that means you are way too low on the CRF scale :)
[19:39] <JEEB> and you will get used to it
[19:39] <[twisti]> so higher crf = worse quality ?
[19:39] <JEEB> rather call it higher compression (unrelated to compression efficiency)
[19:39] <JEEB> because it not necessarily looks worse
[19:40] <JEEB> after finding your CRF value of choice, you then start poking the presets
[19:40] <JEEB> and pick the slowest that is still fast enough for your use case
[19:41] <JEEB> now, the CRF *is* affected by such things as the video's frame rate, resolution and the internal settings (poked by the presets), so you might have to adjust the CRF a bit after finding the preset matching your needs, but generally these changes are not big
[19:42] <JEEB> for example if you encode the exactly same clip with the same crf value with, say, preset slow and preset placebo, the placebo one will end up most probably a bit bigger
[19:42] <JEEB> this is due to the encoder "seeing" more things, and you would have to adjust the crf value to compensate if you really care
[19:43] <danomite> is it possible to have a copy stream playable immediately ?
[19:43] <JEEB> on the other hand if you compare one of the faster presets and a slower preset, then the compression efficiency gets better so much that the slower preset's output will most probably end up quite a bit smaller
[19:44] <JEEB> anyways, point being that settings and content affect the CRF so you might have to adjust it depending on various things :)
[19:44] <iive> danomite: mostly depends on the output format/muxer. e.g. .nut should do it.
[19:45] <[twisti]> life was easier back when i could just click a torrent and have things :(
[19:45] <[twisti]> thanks for your input
[19:45] <[twisti]> seems like i have some trial and error ahead of me
[19:45] <JEEB> that said, if you encode a single TV series with similar content then a single CRF value should be just fine for it if you are encoding it at the same resolution, after you have found your preferred preset and CRF value
[19:45] <danomite> I need the output to be mp4 guess i'll just wait to be a segment behind
[19:45] <JEEB> yeah, first pick the crf value, then tweak the preset and finally do some final tweaking of the crf in case you feel you need such
[19:46] <JEEB> [twisti], now imagine how hard this was when we didn't have something as useful as CRF or such a simple system to set different compression efficiency/encoding speed ratios
[19:47] <JEEB> pulling bit rates out of your arse and then trying to tweak those
[19:47] <JEEB> and then having to look at all the settings in an encoder and trying to find a good spot with compression efficiency and speed
[19:55] <ecraven> greetings :) I have a legacy real media RV40 file that no media player I've tried on linux can play successfully. Would someone here maybe be kind enough to just have a short look on whether this is a serious problem? The file is at http://www.datafilehost.com/d/63a8ce3f  (2.2MB), 57 seconds of black and no audio
[19:58] <ecraven> debianuser: oh, with mplayer these files actually seem to play... I tried mpv, assuming it would be the same :-/
[20:01] <ecraven> but audio doesn't work, ffcook seems to have problems :-/
[20:03] <[twisti]> JEEB: once i picked CRF, preset will only affect file size and encoding duration, not quality ?
[20:05] <JEEB> [twisti], "the CRF *is* affected by such things as the video's frame rate, resolution and the internal settings (poked by the presets), so you might have to adjust the CRF a bit after finding the preset matching your needs, but generally these changes are not big"
[20:05] <JEEB> as I quote myself
[20:06] <JEEB> the CRF depends on the internals that are switched around by the presets, but that tweaking is generally small, if any is needed
[20:06] <[twisti]> just making sure i understood correctly
[20:08] <JEEB> basically since the crf value's results can differ between presets due to the internal behavior changing, you might need to tweak the crf value afterwards a bit. but yes, preset controls compression efficiency
[20:09] <JEEB> so in theory the most optimal way is to first pick the preset and then the CRF, but if you are OK with slow encodes then even testing the CRF values becomes slow :P Thus it's better to get a feel with the medium preset (the default) first, and then tweak if tweaks are needed.
[20:11] <danomite> Is there an ffmpeg feed and ffserver example for streaming mp4
[20:53] <miasma> hi. is it true that subtitle conversion (hdmv_pgs_subtitle (pgssub) -> mov_text (native)) is not possible with ffmpeg? is it from bitmaps to text?
[20:55] <sacarasc> Yes, it's bitmap to text.
[20:55] <sacarasc> You'd need an OCR program.
[20:56] <miasma> ok thanks. i guess what i could try is to extract the subtitles into a separate file and use it if the player supports
[21:01] <miasma> sacarasc: any suggestions if there are standalone bitmap subtitle formats?
[21:02] <miasma> my problem originally is, i have some matroska files with dual-audio, dual-subtitle stuff (from bluray). they're too slow to play on raspberry pi for some reason. without subtitles no problem
[21:02] <sacarasc> SubRip and SubtitleEdit will apparently do it on Windows... Dunno about any other OS.
[21:04] <miasma> i guess i could try without ocr'ing the subtitles. ffmpeg just doesn't seem to output this format
[21:04] <miasma> maybe there's no standalone subtitle format for this
[22:32] <ObsequiousNewt> I can use the -ss option before the input to modify audio, but it has no effect when I use it before video. Why? (Log: http://pastebin.com/7tshimna)
[22:34] <kepstin-laptop> ObsequiousNewt: first off, you're using libav; not ffmpeg - does it behave any differently when you use ffmpeg?
[22:34] <ObsequiousNewt> I'm on ubuntu; I can't install it so easily
[22:34] <ubitux> it's still not deployed on ubuntu?
[22:35] <kepstin-laptop> no, it's only in debian unstable
[22:35] <ubitux> it's in debian/unstable nowadays
[22:35] <ObsequiousNewt> Nope.
[22:35] <ubitux> mmh i wonder how long it will take until they sync
[22:35] <kepstin-laptop> ubitux: won't be until *at least* the next ubuntu release.
[22:35] <kepstin-laptop> so april next year at the earliest
[22:35] <ubitux> well, they don't have an unstable as well?
[22:36] <ObsequiousNewt> *sigh* Okay, I'll try installing it.
[22:41] <ubitux> ObsequiousNewt: you can request for support on #libav for avconv
[22:41] <ObsequiousNewt> Ah, thank you
[22:43] <kriskropd> i think i already know the answer to this, but stupid questions will be : Does ffmpeg support an kind of screenrecording on macintosh? like x11grab?
[22:47] <danomite> I'm trying to do faststart in ffmpeg but I keep getting a moov atom error: http://pastie.org/private/llufzyknaz8mfiqdz045w
[22:48] <sacarasc> Does it work if you do it to a file? Also, don't you need to do segments when streaming MP4?
[22:50] <danomite> sacarasc, my goal is to stream mp4, let me try with a file
[22:50] <kepstin-laptop> danomite: the '-movflags faststart' requires rewriting the file after encoding is complete; It can't be done streaming
[22:50] <kepstin-laptop> (mp4 is inherently unsuitable for any sort of live streaming)
[22:51] <danomite> I need to play a live stream in a browser what's a good format?
[22:51] <sacarasc> danomite: I think http://ffmpeg.org/ffmpeg-all.html#segment_002c-stream_005fsegment_002c-ssegment might work for MP4 streaming...
[22:52] <kepstin-laptop> at the moment? it has to be a segmented format, like HLS or DASH, browser support varies
[22:52] <kepstin-laptop> or you could do webrtc, I suppose
[22:52] <kepstin-laptop> or there's always flash with rtmp.
[22:54] <danomite> segmenting sounds like a can of worms, would it be easy enough to to transcode the format to flv and use flash?
[22:54] <kepstin-laptop> you'd have to run a flash media server to handle doing the rtmp; then you'd have ffmpeg send the stream via rtmp to the flash media server which rebroadcasts it.
[22:56] <kepstin-laptop> keep in mind that you only need this if you're doing stuff live; if you don't need live then just pre-process the file before uploading it and everything will be happy.
[22:57] <danomite> Live is key, i'm not married to any format just want it to be easy to setup and play
[22:57] <danomite> I don't want to re- serve it again after ffmpeg
[22:57] <danomite> err ffserver
[23:01] <danomite> btw encoding to file works
[00:00] --- Thu Nov  6 2014