[Ffmpeg-devel-irc] ffmpeg.log.20120319

[burek]

[00:19] <level09> how do I convert a video keeping same quality ?
[00:21] <sacarasc> Doing a lossy conversion will always lose something. Though you can do some things to minimise this, which depends on codec and settings you use.
[01:08] <babloid> hello
[01:46] <Cxshgfvg> anyone have a moment to talk about a possible portability issue?
[01:52] <gilead> hi! I'm trying to convert a Theora/ogv clip and ffmpeg fails to work with "Stream #0.0: Data: skeleton" with the error being: "Error while opening encoder for output stream #0.0 - maybe incorrect parameters such as bit_rate, rate, width or height" -- I tried to read the man page but can't find anything which would allow me to remove a stream. Help?
[01:59] <gilead> uh, never mind, it worked when I tried with xvid but the output is still garbled :( OpenShot doesn't handle my ogv file properly, neither does ffmpeg/mencoder/mplayer; Totem and VLC display it OK :(
[02:00] <Cxshgfvg> hm, guess not.  ohwell.
[02:03] <gilead> VLC has a conversion feature which did the trick!! Ass saved ;)
[02:04] Action: gilead shuts up
[02:35] <znf> Can you edit a feed's entry from MPEG4 High 3.1 to Base 3.0 without actualy re-encoding the content?
[03:05] <vallor> oops, nevermind, figured it out :)
[03:05] <vallor> (deleted here, question about using -loop 1)
[03:05] Action: vallor waves
[04:00] <donkdonk> Hello! I admit i am struggling to read the docs. any idea how to make this conversion? http://pastebin.com/rQ84hmzW
[04:01] <donkdonk> i have a video i want to reduce the quality to match my other videos. any pointers would be appreciated.
[05:16] <param> Hi, I just followed instructions on http://ubuntuforums.org/showthread.php?t=1392026 to use ffmpeg to create a screencast. However ffmpeg just hangs when I launch it and I have to send a SIGINT to it twice before it closes. It always creates an output file of 623 bytes that contains nothing.
[05:27] <param> please ignore - I am reading the man page now and playing with it - got as far as recording video. need to figure out audio next
[07:34] <zap0> is there a way to generate a thumbnail animation from a video?
[07:42] <grepper> zap0: you mean like a gif ?  ffmpeg can output gif
[07:43] <zap0> yes.
[07:43] <zap0> the docs say there is a command  thumbnail=50    i run ffmpeg, it says no such command.
[07:47] <zap0> how do you specify a period of which frames to save?
[07:48] <zap0> i got it outputing 5 frames, but its the same 5 frames
[07:48] <zap0> i want the 5 spread accross the whole video
[07:57] <zap0> found it on a random web site.
[10:35] <gxk_> have avi file with raw video (bgr24). how to check that all frames are good, not corrupted ?
[10:37] <ubitux> check ffprobe -show_packets, and ffprobe -show_frames
[10:37] <ubitux> show_frames actually doing the decode
[10:42] <gxk_> @ubitux: ffprobe got seg fault
[10:43] <ubitux> are you using latest git?
[10:43] <ubitux> if yes, please share the sample
[10:51] <gxk_> @ubitux: No, using ubuntu 10.04 default
[10:52] <ubitux> ubuntu isn't using ffmpeg, even it is called "ffmpeg"
[10:52] <ubitux> it's using a fork called libav
[10:53] <ubitux> please upgrade to ffmpeg and try again, for instance using https://launchpad.net/~jon-severinsson/+archive/ffmpeg
[10:53] <ubitux> or building it yourself (recommended)
[10:53] <ubitux> if you don't want to waste time, you can share a sample and i can check if i'm able to decode it here
[13:17] <latelate> hi, is it possible to mux an encoded audio track with video without decoding & re-encoding it? i have a aac audio track & raw video which i want to combine & encode to mp4
[13:21] <cbsrobot> latelate: of course
[13:22] <cbsrobot> ffmpeg -i video.file -i audio.file -c copy output.mp4
[13:23] <ubitux> if the data is raw you might need to specify the type of the input
[13:23] <latelate> oh sorry, im making a program & using the C library, not the command line tool
[13:25] <latelate> so would it work if i just av_read_frame the aac file & then av_write_frame
[13:56] <JacobS2> anyone knows the proper way to use the pan filter ? I am trying to take a stereo input and mute one channel and get a stereo output with one channel muted
[13:56] <JacobS2> this is my command: -rtbufsize 100000000  -f dshow -i video="screen-capture-recorder":audio="SoundMAX Digital Audio" -vcodec  libx264 -preset ultrafast -tune zerolatency -r 10  -async 1 -f pan="stereo:c2=c2" -ab 32k -ar 22050 -bsf:v h264_mp4toannexb -b 614400 -f mpegts udp://192.168.5.215:48550
[16:57] <JacobS2> can anyone tell me what is the correct syntax for using audio filters in ffmpeg and ffplay ? I am trying to use the pan filter with no success so far
[18:33] <kriegerod> JacobS2, you need to find and apply a couple of patches from ffmpeg-devel ML, afaik they're not applied to upstream yet
[18:33] <kriegerod> and use -af (or -f:a) option instead of  just -f
[18:34] <kriegerod> author of patches is Clement Boesch, and subject he posted patches under is sth like "audiofilters in ffmpeg"
[18:34] <kriegerod> nearly month ago
[18:43] <MrJones_> hi
[18:47] <MrJones_> I have a format context which I allocated with avformat_alloc_context and for which I opened a file successfully (returned 0). now I got a stream index av_find_best_stream
[18:48] <MrJones_> and avcodec_open2 works on formatcontext->streams[streamindex]->codec without error
[18:48] <MrJones_> but then formatcontext->streams[streamindex]->codec->channels is 0, same as formatcontext->streams[streamindex]->codec->sample_rate
[18:49] <MrJones_> and I have no idea why
[18:50] <MrJones_> formatcontext->streams[streamindex]->codec->codec_type is AVMEDIA_TYPE_AUDIO
[18:50] <MrJones_> so should be an audio stream as expected
[19:15] <ubitux> kriegerod: they're not applied and i'm afraid they won't soon
[19:15] <ubitux> the patch on the ml is a WIP (and the posted version is broken for a stupid mistake)
[19:15] <ubitux> applying it means dropping several features
[19:16] <ubitux> that need to be in the filterchain before we can go ahead
[19:16] <kriegerod> ubitux: but at last the interfacing function for copying from AVFilterBufferRef to audio AVFrame can be applied imemdiately
[19:16] <ubitux> ah yeah, forgot this one, i was busy lately
[19:16] <ubitux> i'll try to go back on this
[19:17] <ubitux> JacobS2: ffplay -f lavfi 'amovie=6channels.mp3,pan=2:...'
[19:17] <ubitux> that's the current workaround for audio filtering
[19:18] <ubitux> MrJones_: you need to find_info_stream
[19:18] <ubitux> MrJones_: check avformat_find_stream_info()
[19:19] <ubitux> look at the examples (doc/examples) and/or for instance ffprobe.c for a real case
[19:25] <MrJones_> ubitux: I checked ffplay.c
[19:26] <MrJones_> but, to be honest, the code is hideous
[19:26] <MrJones_> dubious variable naming ("is", "ic", ...), no comments at the top of functions explaining what they do in overall, large code paragraphs without a single explaining comment, ...
[19:26] <ubitux> input stream, input context?
[19:26] <MrJones_> however, I shall check avformat_find_stream_info
[19:26] <MrJones_> I have no idea?
[19:27] <MrJones_> probably
[19:27] <MrJones_> but without being familiar with FFmpeg, the code is almost unreadable
[19:27] <ubitux> doc/examples/filtering_video.c:    if ((ret = avformat_find_stream_info(fmt_ctx, NULL)) < 0) {
[19:27] <ubitux> check this file
[19:27] <ubitux> ffprobe.c:    if ((err = avformat_find_stream_info(fmt_ctx, NULL)) < 0) {
[19:27] <ubitux> check also this one
[19:27] <ubitux> they are simple
[19:27] <MrJones_> ok
[19:27] <MrJones_> probably ffplay is just too complex
[19:27] <MrJones_> anyway, is/ic should be renamed to inputstream/inputcontext
[19:27] <MrJones_> even if that means more typing, it would vastly increase readability
[19:28] <MrJones_> and a few more comments would also help..
[19:28] <ubitux> not worth the change, but whatever :)
[19:28] <MrJones_> I usually read the doxygen documentation
[19:28] <ubitux> ffplay is not a demonstration of the api
[19:29] <MrJones_> it is good when I know which functions I need to use, but it is hard to guess the right ones
[19:29] <MrJones_> hm ok
[19:29] <ubitux> check the doc/examples then :p
[19:29] <MrJones_> I checked for an examples folder but just missed it for some reason :D
[19:29] <MrJones_> thanks for pointing it out :)
[19:42] <MrJones_> ubitux: thanks, now it works :)
[21:05] <JacobS2> @ubitux: how can I use lavfi with dshow input in ffmpeg and with udp input in ffplay ? this is my ffmpeg command: -rtbufsize 100000000 -f dshow -i "video=screen-capture-recorder:audio=Stereo Mix (IDT High Definition" -vcodec libx264 -preset ultrafast -tune zerolatency -r 10 -async 1 -ab 32k -ar 22050 -bsf:v h264_mp4toannexb -b 614400 -f mpegts udp://192.168.5.215:48551
[21:37] <akua> hi. I am using libswscale library to convert RGB into YUV-420p. Normally this works well, but I am now converting very small image chunks and if I do this I get memory overruns and segfaults. I think it has something to do with the small input image segments. They are sometimes as small as 30 pixels square for example. They are always a multiple of 2, but nothing larger.
[21:38] <akua> Is there a size limit that the images must be at least for swscale to work correctly? Or do the images have to be at least a certain width & height?
[22:25] <Jordan_> how do i get details of a video like codec and container
[22:25] <Tjoppen> ffprobe
[22:27] <Jordan_> kcan i just dl that?
[22:28] <Tjoppen> since you're in #ffmpeg I'm assuming it's already installed
[22:29] <Jordan_> i just dled it
[22:35] <Jordan_> what is the diff in h.264 and mpeg4
[22:38] <Shoe|AFK> what is best way to convert  .webm video to  .vorbis audio only
[22:39] <JEEBsv> ffmpeg -i derp.webm -vn -acodec copy out.ogg
[22:39] <JEEBsv> because webm can only have vorbis in it
[22:40] <JEEBsv> -> -vn (video:none)
[22:40] <Jordan_> how do i find out what the containter is?
[22:40] <JEEBsv> -> acodec copy (copy the audio stream)
[22:40] <JEEBsv> -> out.ogg output file name
[22:40] <Shoe|AFK> jeeb that doesn't reencode the audio.. right?  just change container
[22:41] <JEEBsv> COPY THE AUDIO STREAM
[22:41] <JEEBsv> -acodec _copy_
[22:41] <Shoe|AFK> this is first time i saw .webm container. is this new
[22:41] <JEEBsv> webm is a format (vp8 and vorbis in raped matroska)
[22:42] <Shoe|AFK> raped?
[22:42] <JEEBsv> very very limited feature set
[22:42] <Shoe|AFK> matroska uses .mkv though
[22:42] <JEEBsv> or mka or whatever, yes
[22:42] <JEEBsv> webm is just a naming for this specific subset of matroska :P
[22:43] <Shoe|AFK> then what is webm
[22:43] <JEEBsv> or well, google made this format
[22:43] <JEEBsv> which is a subset of matroska + vp8 and vorbis
[22:43] <Shoe|AFK> there are many subset of mastroska?
[22:43] <JEEBsv> ...
[22:43] <JEEBsv> as many as you can think of
[22:43] <JEEBsv> a subset is a subset
[22:44] <JEEBsv> and this is a specific subset of matroska specified by google and the specifications for which you can read on the webm web site :P
[22:44] <Jordan_> is mpeg2video a codec or container or neither
[22:47] <Shoe|AFK> is flv subset of matroska too
[22:47] <JEEBsv> no
[22:47] <JEEBsv> flv is a completely separate container, made by adobe
[22:48] <Shoe|AFK> i see
[22:51] <Jordan_> ...
[22:51] <JEEBsv> Jordan_: mpeg2video sure sounds like a video format
[22:52] <Jordan_> so it is a standard
[22:52] <Jordan_> not an actual codec
[22:52] <JEEBsv> uhh
[22:52] <Jordan_> or container
[22:52] <JEEBsv> I have no idea what exactly ffmpeg calls mpeg2video
[22:53] <Jordan_> i think mpeg2video is a specification
[22:53] <Jordan_> right
[22:53] <JEEBsv> but mpeg-2 IIRC contains a video codec, and the mpeg-ps/ts containers. I do think that those two are called somehow differently, thus I think ffmpeg probably calls a video track with MPEG-2 like that
[22:53] <JEEBsv> well, all of those have specifications
[22:53] <JEEBsv> All MPEG formats have
[22:54] <JEEBsv> or well, all formats have to have SOME kind of specification
[22:54] <Jordan_> i know but when you say mpeg you are referring to a spec not an implementation
[22:54] <JEEBsv> MPEG formats just tend to have PUBLIC ones
[22:54] <JEEBsv> uhh
[22:55] <Jordan_> uhh as in stupid question or you don't know
[22:55] <JEEBsv> when someone says only mpeg/MPEG, chances are good he or she is talking about the MPEG (Meh Pictures Experts Group)
[22:55] <JEEBsv> Moving/Motion, whichever that was
[22:55] <Jordan_> mpeg1/2/3/4
[22:55] <Jordan_> so how do i use probe to find out container
[22:56] <Jordan_> it just says Vieo: mpeg2video (Main)
[22:56] <JEEBsv> pastebin.com the whole log :P
[22:56] <JEEBsv> also, mpeg3 never came to be, but those are all MPEG's specification groups
[22:57] <Jordan_> http://pastebin.com/kUvY7PfF
[22:57] <Jordan_> ok so h.264 is an implemenation mpeg4 is a spec
[22:57] <JEEBsv> I don't fully remember what MPEG-1 contained but it was at least the MPEG-1 video codec, and MP3 (MPEG-1 Layer 3)
[22:57] <JEEBsv> no
[22:57] <JEEBsv> H.264 is one specification (MPEG-4 Part 10) within the MPEG-4 specification group
[22:58] <JEEBsv> just like the MPEG-4 container is Part 2 and IIRC Part 12?
[22:58] <JEEBsv> no wait
[22:58] <JEEBsv> MPEG-4 Part 2 is a video codec
[22:58] <Jordan_> why is this so confusing
[22:58] <JEEBsv> the specification that xvid and divx, as well as the video codec called 'mpeg4' follow
[22:59] <JEEBsv> (within ffmpeg)
[22:59] <JEEBsv> Jordan_: it really isn't, now let me see the paste...
[22:59] <JEEBsv> ok
[23:00] <JEEBsv> Input #0, mpeg <- this is the container line
[23:00] <JEEBsv> now I think this is mpeg-ps that ffmpeg is meaning
[23:00] <JEEBsv> although you'll have to check somewhere to make sure what exactly it is :P
[23:01] <JEEBsv> then you have streams within that container listed
[23:01] <JEEBsv> one MPEG-2 Video track
[23:01] <JEEBsv> and one AC-3 Audio track
[23:01] <Jordan_> so mpeg4 is a group of formats
[23:01] <JEEBsv> yes
[23:01] <JEEBsv> it has a lot of stuff >_>
[23:01] <Jordan_> its up to the codec to get it in those formats
[23:01] <JEEBsv> uhh
[23:02] <JEEBsv> I don't get what you just said
[23:02] <JEEBsv> mpeg-4 contains multiple video and audio codecs, as well as a container
[23:02] <Jordan_> codec being the thing compresses the data in the mpeg4 formats
[23:02] <JEEBsv> (plus other stuff, but we can leave that out for a moment)
[23:03] <JEEBsv> also, s/codecs/formats/
[23:03] <JEEBsv> a codec is a 'Coder/Decoder'
[23:03] <Jordan_> ok
[23:04] <Jordan_> how do i find out what #0 mpeg is
[23:04] <JEEBsv> documentation/source code
[23:04] <JEEBsv> but I think it means MPEG-PS (Program Stream)
[23:05] <JEEBsv> and the #0 is 'first input file'
[23:05] <JEEBsv> listing begins from zero
[23:05] <Jordan_> oh i see the #0 is not part of it
[23:07] <Jordan_> http://ffmpeg.org/general.html#File-Formats?
[23:07] <Jordan_> http://ffmpeg.org/general.html#File-Formats ?
[23:08] <JEEBsv> oh, it could be MPEG-1 system as well.
[23:08] <JEEBsv> it doesn't mention the internal name so lol
[23:10] <JEEBsv> I guess you could try outputting ffmpeg -formats to a file and check what that says
[23:10] <Jordan_> is there an easier way to get video details
[23:11] <JEEBsv> not really, this is as simple as it gets. You got a relatively good info on the container, and the tracks in it
[23:11] <Jordan_> tracks?.?.
[23:12] <Jordan_> why would anyone be using mpeg2video btw
[23:12] <JEEBsv> when multiple things are put into a container, if nothing else video, audio and subtitles are called 'tracks'
[23:12] <Jordan_> why not mpeg4 part 10
[23:12] <JEEBsv> that looks like something that came out of a DVD
[23:12] <Jordan_> mpeg2?
[23:13] <JEEBsv> yes, DVD is MPEG-2 video and AC-3/DTS/PCM audio
[23:13] <Jordan_> i see
[23:13] <Jordan_> well its 200mb for 5minutes
[23:14] <Jordan_> kind of shitty if you ask me
[23:14] <JEEBsv> looking at the info dump you pastebinned me I'd pretty surely say it's just a remux of a DVD :P
[23:14] <JEEBsv> so it makes sense in that way, it's just the stuff off of DVD copied as-is
[23:15] <Jordan_> no someone is recording video
[23:16] <anddam> hello
[23:16] <JEEBsv> ...or a camera that uses those codecs, or digital tv
[23:16] <JEEBsv> most probably digital tv or DVDs
[23:16] <JEEBsv> the bitrate on that looks like DVD more, but loldunno :V
[23:17] <JEEBsv> camera isn't that probable because they don't usually want to put stuff like AC-3 there
[23:17] <Jordan_> why
[23:17] <JEEBsv> because people tend to ask royalties for implementing it in something?
[23:17] <JEEBsv> although DTS is even more well known in that area
[23:18] <JEEBsv> of course if I was encoding something myself for web or something I'd be using H.264/MPEG-4 Part 10
[23:18] <JEEBsv> for video
[23:18] <anddam> I'm getting    [ipod @ 0x7fe49b84da00] track 1: could not find tag, codec not currently supported in container
[23:18] <dj_who> hi, why if I use -ss time -t time2 -ss is working fine (start of the clip is in the right place) but -t is not working properly (clip is shorter than it should be) i use -ss for output file
[23:18] <anddam> where can I check what codec are available in a certain container?
[23:24] <Jordan_> So say a company is video recording some manufacturing process, are they allowed to use mpeg4 part 10 or do they need some license and pay royalties
[23:26] <JEEBsv> Jordan_: depends. If the camera already encodes stuff to H.264 then chances are quite high that the makers of the camera already paid the related royalties
[23:26] <Jordan_> this is bs
[23:26] <JEEBsv> if you for example just put cameras that give you raw feed into a computer, and are making an encoding system yourself
[23:27] <JEEBsv> and are going to be providing people binaries of that software
[23:27] <Jordan_> no this is for their own internal uses
[23:27] <JEEBsv> MPEG-LA will want to have some words with you
[23:27] <JEEBsv> well, if it's not going anywhere I don't think anyone will ever care what's happening inside
[23:28] <Jordan_> ok i do have software that plays various videos
[23:28] <Jordan_> what if i just play it... or manipulate it in some way
[23:28] <Jordan_> nvm i don't care i'm not worrying about it
[23:28] <JEEBsv> the licenses for various formats are available around
[23:29] <JEEBsv> you should look at them and possibly consult a lawyer if you want to check something
[23:29] <JEEBsv> ffmpeg-wise all we care about is that you follow the software license this software is written under :)
[23:29] <JEEBsv> (L)GPL, that is
[23:56] <MrJOnes> JEEBsv: what about projects like VLC? are they tolerated or do they actually pay royalties aswell?
[23:56] <MrJOnes> just curious
[23:56] <MrJOnes> or SMPlayer
[23:57] <JEEBsv> MrJOnes: projects usually either don't provide official binaries, host themselves in a country where software patents have less legal ground, or just don't give a flying pigworth
[23:57] <MrJOnes> yea but I wondered what exactly of those VLC is doing :)
[23:58] <MrJOnes> or how much non-commercial projects are usually tolerated in practise
[23:58] <JEEBsv> you should ask them, but I think they chose to be in france for the legalese
[23:58] <JEEBsv> also yes, non-commercial open source projects aren't really a place most people would ask to get a license
[23:59] <JEEBsv> except for friends like DTS licensing or maybe real
[23:59] <JEEBsv> DTS licensing LOVES to send out messages
[23:59] <MrJOnes> hmmmm
[23:59] <MrJOnes> I already wondered whether those patents are actually relevant in Germany
[23:59] <JEEBsv> depends, you should ask a lawyer to be sure
[00:00] --- Tue Mar 20 2012