[Ffmpeg-devel-irc] ffmpeg.log.20140416

burek burek021 at gmail.com
Thu Apr 17 02:05:01 CEST 2014


[01:48] <pzich> Hmm, is the handler_name stream metadata not settable? I've been trying to do it with -metadata, -metadata:s:v:1, and a bunch of other variations, and it always seems to not apply.
[02:29] <watsonkp> Ive so far failed to get the correct output frame rate when transcoding h264 to vp8 with the libav* libraries. I created a successful encode of the Sintel mkv as webm(vp8/vorbis) using a modification of the transcoding.c example, but the resulting file is 48fps unlike the 24fps of the original and the output of the ffmpeg command Im trying to mimic.
[02:29] <watsonkp> I noticed ffprobe produces a tbc of double the fps for this and other h264 videos, while the tbc of the resulting vp8 stream produced by the ffmpeg command is the default 1000. The stock transcoding.c example copies the time base of the decoder to the encoder AVCodecContext, which is 1/48. Running the ffmpeg command through gdb it looks like the time base of the AVCodecContext is set to 1/24, but making that change alone only causes the resulting video to
[02:29] <watsonkp>  be twice the duration at 24fps.
[02:29] <watsonkp> I havent made any progress in a while, so any guidance would be very much appreciated. My code is http://pastebin.com/16RU3qmD and the ffmpeg command Im trying to mimic is http://pastebin.com/3XDnjaKK
[02:31] <Bray90820> So when i run "ffmpeg -i VIDEOFILE -acodec libmp3lame -metadata TITLE="Name of Song" OUTPUTFILE.mp3" it is telling me "Output file #0 does not contain any stream"
[02:31] <Bray90820> On ubuntu
[02:32] <pzich> and does it work correctly when you don't have the -metadata flag?
[02:36] <Bray90820> Here is the pastbin of the output
[02:36] <Bray90820> http://pastebin.com/raw.php?i=gf2L4pfp
[02:38] <klaxa> you are using avconv and not ffmpeg, see #libav
[02:38] <Bray90820> join #libav
[02:38] <klaxa> it also appears that your input file has no audio stream
[02:38] <Bray90820> oops
[02:39] <Bray90820> I am dumb
[02:39] <Bray90820> I was using the wrong file
[02:39] <Bray90820> ok facepalm on my part
[02:40] <Bray90820> And now it's working
[02:40] <Bray90820> Can someone tell me what folder it's going to as well
[02:41] <pzich> the one you're currently in
[02:41] <pzich> looks like
[02:41] <Bray90820> Alright i'll just have to look for it myself
[02:41] <Bray90820> Oh well
[02:41] <Bray90820> Atleast you tried
[02:42] <pzich> run `pwd` from wherever you just ran that command
[02:42] <pzich> it should be in that folder
[02:43] <Bray90820> It's not in that folder
[02:43] <Bray90820> But if i rerun the command it says the file already exists
[02:44] <Bray90820> It's in /home
[02:44] <Bray90820> Found it
[02:44] <pzich> what did `pwd` show?
[02:45] <Bray90820> wait are you saying it should be in the same directory as the original file
[02:47] <Bray90820> pzich:
[02:47] <Bray90820> are you saying it should be in the same directory as the original file
[02:48] <pzich> no, it's in whatever directory you're `cd`ed to, which is your home folder initially
[02:48] <Bray90820> Ahh then yes it was there
[02:48] <Bray90820> also does teh command lose any quality or is it a bit for bit copy
[02:49] <pzich> it'll depend on if you're changing formats, among other things
[02:49] <Bray90820> How would i find what format/extension to use so i don't loose quality
[02:51] <pzich> do you know if all of your movie files have WAV audio?
[02:52] <Bray90820> The most i know right now is the dvd has LPCM and AC#
[02:52] <Bray90820> AC3
[02:53] <pzich> you could try a hack like this, that starts by reading the input stream types and tries to get the correct extension for that. doesn't seem like the best or most robust solution though: http://www.hydrogenaudio.org/forums/index.php?s=6a216fed48d110e324d62edffa1b5909&showtopic=83421&view=findpost&p=721428
[02:59] <pzich> ugh, as for my problem, it looks like those metadata settings are hardcoded in libavformat/movenc.c :(
[03:00] <Bray90820> Well i have slightly more information now PCM Stereo 24kHz/24-bit
[03:00] <Bray90820> Idk if that helps at all
[03:01] <Bray90820> Wait a second
[03:01] <Bray90820> typo
[03:01] <Bray90820> PCM Stereo 48kHz/24-bit
[03:01] <Bray90820> that's teh correct one
[03:03] <Bray90820> Does that help at all
[03:04] <Bray90820> pzich: does that information help at all
[03:06] <watsonkp> If it's an audio type that I can use easily I'll use the option "-c:a copy" to keep the stream as it is. If it isn't then I'll transcode it to a lossless codec like flac.
[03:07] <Bray90820> I think it's wav but I don't really know
[03:07] <Bray90820> It's a dvd album
[03:11] <watsonkp> I'm not particularly familiar with wav. My first guess would be "ffmpeg -i input_file -map 0:a -c copy output_file.wav"
[03:11] <Bray90820> That's what i am assuming but i get a very low file size
[03:12] <Bray90820> way worse then mp3 even
[03:12] <Bray90820> well the cd wien imported as mp3
[03:13] <Bray90820> when
[03:14] <watsonkp> Couls you pastebin the output from "ffprobe input_file" so we can all see what is inside it?
[03:14] <Bray90820> the vob or the wav
[03:15] <watsonkp> vob
[03:16] <Bray90820> http://pastebin.com/raw.php?i=J8AZ1Emz
[03:19] <Bray90820> It looks like it is using AC3 instead of LPCM
[03:21] <watsonkp> Unless you really want pcm, and it looks like some variation of pcm to me, I'd just encode it as flac (lossless) and be done with it. To do that omit the "-c copy" and use .flac on your output.
[03:22] <Bray90820> Actually my perferd output would be flac
[03:23] <Bray90820> I don't see "-c copy" in my original command
[03:24] <watsonkp> What was your original command?
[03:25] <Bray90820> ffmpeg -i '/home/aaron/Desktop/VIDEO_TS/Midnight.VOB' -acodec libmp3lame -metadata TITLE=midnight2 midnight2.wav
[03:26] <watsonkp> ffmpeg -i '/home/aaron/Desktop/VIDEO_TS/Midnight.VOB' -metadata TITLE=midnight2 midnight2.flac
[03:26] <Bray90820> Thanks
[03:27] <Bray90820> Why is the flac much bigger then the wav
[03:28] <watsonkp> Sounds like something is wrong with the wav. Flac has been foolproof in my experience.
[03:29] <Bray90820> hum
[03:30] <Bray90820> Whatever
[03:30] <Bray90820> Flac is what I normally use anyways
[03:31] <Bray90820> Now i just need to figure out how to import a bluray disc and i am good to go
[03:32] <Bray90820> Do you know how by any chance
[03:36] <Bray90820> Yea the wav is F***ED
[03:36] <Bray90820> I can't even seek it on my mp3 player
[06:39] <kcynice> hello, i found ffplay can't stop playing, any help?
[06:44] <relaxed> kcynice: try -autoexit
[06:46] <kcynice> oh. thanks. i tried it ok now
[06:51] <kcynice> however, if i want to modify demuxing-decoder example to work like ffplay? im puzzled by ffplay
[06:51] <kcynice> if i comment the line of writing decoded buffer into yuv file, the loop would be infinite
[07:29] <Zeranoe> Wow xvid came out with 1.3.3. I thought that project was dead
[07:36] <kcynice> why?
[14:20] <Ricko_> hi every one, im trying to compile the last version of ffmpeg on debian but it seems i have to uninstall the existing version and several libs can someone explain to me how to proceed pls?
[14:20] <Ricko_> im quite new to this
[14:21] <klaxa|work> https://trac.ffmpeg.org/wiki/CompilationGuide
[14:24] <Ricko_> yes thanx for the link, dont i have to get rid of the previous version before i get the new one?
[14:25] <klaxa|work> depends on what you want to do and how
[14:25] <klaxa|work> i maintain a non-system-wide installation of ffmpeg on my debian server
[14:25] <klaxa|work> although it became system-wide as soon as i added its path to my $PATH variables... hm...
[14:27] <Ricko_> my goal is to compile a framework called upipe wich needs ffmpeg 1.1 up to 2.1.1. I already have an older ffmpeg installed
[14:28] <crow> Hello, i am VDR with softhddevice outplut plugin, which use ffmpeg 2.2 and i am getting an segfault. Is it caused by ffmpeg or softhddevice output plugin from VDR? http://sprunge.us/PEjZ
[14:35] <klaxa|work> Ricko_: you should be able to link that framework against ffmpeg without having to install ffmpeg as a system-wide available package
[14:41] <Ricko_> Klaxa | work: so how do i proceed?
[15:15] <Ricko_> what is the easyest way to get ffmpeg installed on my debian?
[15:15] <ubitux> asking for the upload on https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=729203
[15:16] <ubitux> otherwise, maybe deb-multimedia
[15:22] <Ricko_> im trying to understand the procedure to compile ffmpeg on debian, what is yasm used for?
[15:23] <ubitux> the optimisations
[15:32] <Ricko_> i read that it is an assembler
[15:36] <ubitux> Ricko_: a large part of ffmpeg is hand written (mostly SIMD) assembly, yasm is used to assemble them on x86
[15:37] <ubitux> it is more than recommended that you get it, otherwise ffmpeg might be insanely slow
[16:25] <Ricko_> @ubitux: yeaaaaah did it! thanks for your answers i wanted to understand what i was doing and not just copy lines
[17:19] <Ricko_> what does it mean to configure ffmpeg configured --enable-pic --enable-shared.
[17:25] <c_14> Ricko_: --enable-pic enables Position Independent Code https://en.wikipedia.org/wiki/Position-independent_code and --enable-shared enables building of shared libraries https://en.wikipedia.org/wiki/Shared_libraries
[17:29] <Ricko_> c_14 : thx
[17:34] <c_14> np
[18:12] <share> [libmp3lame @ 0x20edbc0] Queue input is backward in time
[18:12] <share> what am I doing wrong
[18:38] <share> c_14: https://pastee.org/bnvpv
[18:40] <c_14> share: We need the _entire_ command and the _complete_ console output.
[18:45] <share> c_14: ok but you will still complain
[18:45] <share> I've used -loglevel warning
[18:45] <share> c_14: https://pastee.org/f3srg
[18:56] <klaxa> you audio is most likely stuttering, is it not?
[18:56] <klaxa> alsa xruns are something i personally have never solved
[18:56] <klaxa> i don't know how it occurs and how to fix it
[18:56] <klaxa> i use pulse for that now
[19:07] <share> klaxa: well I use pulseaudio
[19:07] <klaxa> try -f alsa -i pulse instead of -f alsa -i hw:1 then
[19:12] <share> ok
[19:14] <share> klaxa: no audio is captured
[19:15] <share> I have 2 input devices..
[19:15] <klaxa> open pulseaudio volume control (pavucontrol is the binary) and see if ffmpeg is recording from the correct device
[19:15] <share> it should be using the first (0)
[19:15] <klaxa> if not you can change the device in the GUI
[19:15] <klaxa> you can also set the device in the command line but that is a bit more complex, but scriptable
[19:15] <share> you are right
[19:16] <klaxa> you can also select your second input as the default recording device in pulse
[19:17] <share> klaxa: when I started recording for the second time this appeared [libmp3lame @ 0x23f2fa0] Queue input is backward in time
[19:17] <share> and pulseaudio used the second input
[19:17] <klaxa> i wouldn't worry about that too much
[19:17] <klaxa> i have that in my encodes to vorbis a lot but i don't hear anything weird
[19:18] <share> aside from that, the other messages are gone
[19:18] <klaxa> in that case it's bound to concatenating multiple files though...
[19:18] <share> at least for now..
[19:18] <share> klaxa: i instructed ffmpeg to overrwrite
[19:18] <share> *overwrite
[19:19] <klaxa> ah no i mean in my case it's probably bound to concatenating a lot of files
[19:19] <klaxa> with different timestamps
[19:19] <share> hm
[19:19] <klaxa> it shouldn't happen on a live recording actually
[19:19] <share> there's a lot of static noise.
[19:19] <share> the audio is analog from a STB
[19:19] <share> hardware issue :(
[19:20] <share> but at least there is no more crackling
[20:17] <troulouliou_dev> hi sorry to ask such a noob question but how is AvProgram array from AvFormatContex used for ?
[20:18] <voip> hello guys, is there some people familar with wowza ?
[20:20] <klaxa> all i know about wowza is that it's written in java. and i don't trust java developers
[20:21] <troulouliou_dev> what kind of situation require the use of avprogram ? is there an example somewhere ?
[20:26] <voip> klaxa, wowza one of the best streamers :))
[20:27] <klaxa> it's time for a better open-source alternative
[20:27] <voip> :)
[20:27] <klaxa> which is, god forbid, not in java
[20:27] <klaxa> i don't believe that java and multimedia mix and scale well
[20:30] <voip> which open-source streamer you use in production environment ?
[20:30] <voip> for iptv
[20:31] <klaxa> none, like i said, it's time for a better open-source alternative [to be implemented]
[20:31] <klaxa> i started playing around with libavformat and avio and stuff, not getting very far so far...
[20:31] <klaxa> i want to write a simple matroska streaming server
[20:32] <voip> i agree 100% it's time for a better open-source alternative, but ungortunatley for now we dindnt have better alternative
[22:10] <jgh-> I'm having trouble publishing an RTMP stream to the latest Wowza Streaming Engine (Wowza 4.0.1) using ffmpeg -re -i input.mp4 -vcodec copy -acodec copy -f flv rtmp://127.0.0.1:1935/live/myStream ... previously this would work with Wowza 3.  Has anyone noticed similar issues? Found a solution?
[22:11] <jgh-> According to the server, the stream is being injested properly...when I play back I get one still frame, no audio.  Seems like it doesn't like the stream somehow
[22:26] <jgh-> ah, strange.  The stream plays back in VLC, so I wonder if the test players are messed up somehow.
[23:53] <ScottSteiner> Is there a faster way to seek?  I'm trying to get a 2 second clip from a video and it takes 45 minutes
[23:54] <c_14> Are you using -ss before the input or before the output?
[23:54] <ScottSteiner> I'm doing "ffmpeg -i input.mkv -ss 02:01:56.5 -to 02:01:59.5 -b:v 10300k -an output.mp4"
[23:54] <ScottSteiner> after
[23:54] <c_14> https://trac.ffmpeg.org/wiki/Seeking%20with%20FFmpeg
[00:00] --- Thu Apr 17 2014


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