[Ffmpeg-devel-irc] ffmpeg.log.20121023

[burek]

[00:45] <njbair_> what's the "standard" WxH for mobile video?
[01:41] <mooglenorph> Hi, where can I find the docs for the drawbox filter?
[01:42] <mooglenorph> Alternately, is there an easier way to accomplish drawing a constant-position black box in my video?
[01:42] <mooglenorph> I have where it should be in pixel offsets and it doesn't change all video file long.
[01:44] <saste> mooglenorph, http://ffmpeg.org/ffmpeg.html#drawbox
[01:44] <saste> or man ffmpeg
[01:46] <mooglenorph> and would I specify it with -filter drawbox=x:y:width:height:color ?
[01:46] <durandal_1707> P3 ppm is supported (decoding)
[01:57] <saste> durandal_1707, good
[01:57] <saste> are you planning to add encoding support, or should i add it to my todo?
[01:57] <saste> mooglenorph, -vf drawbox=...
[01:58] <durandal_1707> saste: no, you have nothing better to do?
[01:59] <saste> durandal_1707, so many things
[03:44] <kode54> damn
[03:44] <kode54> is 2.4Mbps that low for 720x480 at 29.97 fps?
[03:44] <kode54> (MJPEG)
[03:48] <Exatrive> I think so.. just a guess tho.
[03:55] <kode54> that's what I get for trusting ffdshow with 1-pass quality based encoding
[03:55] <kode54> I guess the default of 85 sucks
[03:56] <Exatrive> 85 is pretty low in jpeg when it come to motion jpeg
[03:57] <Exatrive> from my experience it take about 93 or more to get it less artifact in the motion
[03:57] <kode54> next time I'll use 100, since space isn't an issue
[03:57] <Exatrive> but that was with my experienc in virtualdub
[03:58] <Exatrive> yeah if you can get it to do 100% that would be best
[03:58] <kode54> must shoot somebody for making 85 the default
[03:59] <Exatrive> even at 100% tho I'm not sure if that maximazes subsampling quality
[04:00] <kode54> I'm capturing from composite NTSC
[04:00] <kode54> in not so ideal conditions
[04:00] <Exatrive> yeah
[04:00] <Exatrive> ?
[04:01] <kode54> I'm using a USB powered capture device that only has drivers for Windows XP, so I'm running the capture software inside of a virtual machine and feeding it the device through USB passthrough
[04:01] <Exatrive> I would try to capture to lossless format then till your final edit is ready to be reencoded
[04:01] <kode54> assuming that it won't munch the disk space
[04:01] <Exatrive> really?
[04:01] <kode54> 32GB left on that virtual drive
[04:01] <Exatrive> what capture device is that?
[04:02] <kode54> Adaptec Gamebridge
[04:02] <kode54> last I checked, the linux developers who even remotely approach work on the chipset it's based on are uninterested in it because it's a USB powered low latency device, so apparently not designed for serious video capture
[04:04] <Exatrive> yeah I just had a google and linux support is none exsistanct.. and its a pretty old device..
[04:04] <Exatrive> ebay is full of USB devices tho that would work in linux
[04:05] <Exatrive> but unless your archiving a bunch of vhs or something .. prolly not worth it.
[04:05] <kode54> it's only interesting for the occasion when I want to pull videos off my DVR box
[04:06] <kode54> hurray for proprietary black box video recorders
[04:06] <Exatrive> lol
[04:06] <kode54> it even encrypts the videos to the user's account so they can't be replayed when they refurbish the box
[04:08] <kode54> and they're even clumsy enough to not wipe the drives when they refurbish, so you end up with a machine with hours of random shows you can only view the titles and information blocks for
[04:08] <kode54> which you then have to erase one by one
[04:09] <kode54> the only way to mass erase videos is to load up their web interface on a desktop pc (which goes out through the public internet) and check all the videos and click delete
[04:10] <Exatrive> what version is your gamebridge?
[04:10] <kode54> revision a
[04:10] <Exatrive> model/
[04:10] <Exatrive> ?
[04:10] <kode54> avc-1400/1500
[04:11] <kode54> yes, the label says that
[04:11] <kode54> pn asm-0438-0a-a
[04:11] <kode54> *00438
[04:11] <kode54> *01-a
[04:11] <kode54> damn, I screwed that up badly
[04:11] <kode54> asm-00438-01-a
[04:11] <Exatrive> and you have had no luck getting it to install?
[04:12] <kode54> only installs in Windows XP, or from what I've heard, Vista/7 32 bit
[04:12] <kode54> it has no 64 bit drivers
[04:12] <kode54> in fact, Adaptec doesn't even provide a driver download, the only way to get the drivers is from the bundled CD
[04:13] <kode54> another wonderful piece of proprietary hardware
[04:13] <kode54> seems to capture nicely
[04:14] <kode54> if only I had used huffyuv or similar
[04:15] <Exatrive> lol
[04:17] <Exatrive> I capture to lossless MPEG 4 but... almost no editor will even open the .mp4 without crashing hard...
[04:18] <Exatrive> if I capture the same in ffdshow as AVI using similar lossless functions tho.. other programs seem to open it just fine.. not sure what all ffmpeg does in the stream to not allow editors to open it.
[04:20] <Exatrive> as for that device.. yeah not much in the way of x64bit support at all..
[05:07] <svm_invictvs> Heya
[05:08] <svm_invictvs> I was curious, given a raw byte stream, if it was possible to use ffmpeg (or one of its related libraries) to read the SEI data from a raw byte stream, without actually decoding the whole frame.
[05:08] <svm_invictvs> Is that possible, or am I barking up the wrong tree?
[05:47] Action: Exatrive ** WinSys ** Client: HexChat 2.9.3 (x64) ** OS: Microsoft Windows 7 Ultimate  ** CPU: Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz (3.00 GHz) ** RAM: 16364 MB Total (4863 MB Free) ** VGA: NVIDIA GeForce GTX 570  ** Uptime: 279.45 Hours **
[05:47] <Exatrive> lol opps
[06:33] <magn3ts> ergh, wtf do I have to do to get print_format to work?
[06:33] <magn3ts> I'm building ffmpeg from source, surely it would be in there, no? It looks like it was added back in January
[06:35] <magn3ts> ffmpeg version git-2012-10-23  and yet I get "unrecognized option 'print_format'"
[06:36] <magn3ts> oh jesus
[07:23] <ubitux> magn3ts: this is a ffprobe option
[07:29] <magn3ts> ubitux: yeah, my idiot self found that out about an hour ago, my apologies.
[07:29] <ubitux> no worry :p
[08:46] <elkng> I can use "ffmpeg -ss 0:0:33 -t 12 -i file.avi -c:v png %d.png" to get frames in png format of part of video from 33 to 45 second how can I get exact frames, if I want to get frames only from 400 to 500 ?
[09:16] <stclaws> Ah, again: Trying to compile ffmpeg with --enable-librtmp and getting that dreaded ERROR: librtmp not found when doing configure. I have pkg-config installed and PKG_CONFIG_PATH set to just about anything I can think of, but still. Any clue anyone?
[09:16] <elkng> stclaws: do you have librtmp installed ?
[09:18] <stclaws> yes, just installed rtmpdump, and it is there: /usr/local/include/librtmp
[09:18] <stclaws> which is a dir containing amf.h  http.h  log.h  rtmp.h
[09:19] <elkng> try to reboot
[09:19] <stclaws> I ran pkg-config librtmp librtmp/rtmp.h RTMP_Socket directly and no complaints
[09:20] <elkng> "is it possible to use ffmpeg as a video editing library to embed its functionality in other programs, like if I want to get 500th frame and I could use something like ffmpeg_get_frame("/tmp/file.avi", 500, "png"); and it will return pointer to png file structure is it possible to use ffmpeg or one of its libraries this way ?
[09:21] <stclaws> elkng: Reboot? Why would that help?
[09:24] <elkng> if librtmp was freshly installed
[09:25] <stclaws> Is that ever needed on a LInux system?
[09:30] <stclaws> Did anyone here install ffmpeg with rtmp support on a Centos system?
[09:30] <stclaws> or something like that
[09:32] <ubitux> "try to reboot" wtf :)
[09:35] <stclaws> are u on Windows, elkng? :)
[09:37] <stclaws> pkg-config --list-all | grep rtmp
[09:37] <stclaws> librtmp       librtmp - RTMP implementation
[09:38] <stclaws> How come then that the log says: check_pkg_config librtmp librtmp/rtmp.h RTMP_Socket ERROR: librtmp not found
[09:39] <stclaws> I am mystified
[09:51] <elkng> stclaws: was librtmp freshly installed right before compilling ffmpeg ? what the packet manager ?
[10:05] <stclaws> elkng: compiled from source right before compiling ffmpeg
[10:06] <elkng> try to reboot
[10:51] <Exatrive> Anyone who has played with MP4 and sony vegas know what settings my be causing vegas to not be able to render the video stream, but only the audio? I have tried to reporduce the effect in handbreak with verious settings and the only thing that kinda looks like it might effect sony vegas is Subpixle me and Mode decision. cause with certain settings vegas will still render the video but it will be garbage.
[10:52] <Exatrive> in regards to mp4 this is something straight from ffmpeg and having to reincode in handbreak before sony will not barf on it.
[10:52] <Exatrive> in power director another editor it failes to open it also
[10:53] <Exatrive> I have even tried Avidemux 2.6 but that hardcrashes even attempting to open the video.
[10:54] <Exatrive> but.. MPC and VLC can play it fine.. just can't bring into any editor.
[11:37] <brontosaurusrex> Exatrive: convert to some fat I frame format, then edit < perhaps
[11:37] <brontosaurusrex> prores or something
[11:37] <brontosaurusrex> ffmpeg should do it
[14:58] <Aziroshin> Hello.
[15:00] <Aziroshin> I am trying to remux content from mk4 to mp4 (something I unfortunately have to do, as it seems). Command: ffmpeg -i input.mkv -acodec copy -vcodec copy output.mp4, Error: track 1: could not find tag, codec not currently supported in container, Full log: http://pastebin.com/ahYSpdwX
[15:01] <cbsrobot> Aziroshin: you cannot put flac into mp4
[15:01] <ubitux> [mp4 @ 0x63d7b0] track 1: could not find tag, codec not currently supported in container
[15:01] <cbsrobot> you need to transcode it to aac f.ex.
[15:01] <cbsrobot> hi ubitux
[15:01] <ubitux> hey cbsrobot :)
[15:01] <Aziroshin> I should have read the log better.
[15:01] <Aziroshin> Thanks.
[15:01] <ubitux> no lossless codec possible in mp4?
[15:02] <cbsrobot> not that I know of
[15:02] <ubitux> mmh we lack an ALS encoder it seems
[15:02] <divVerent> 15:01:50         @ubitux | no lossless codec possible in mp4?
[15:02] <divVerent> 15:02:03        cbsrobot | not that I know of
[15:02] <divVerent> apple lossless?
[15:02] <divVerent> ah, you meant that
[15:02] <divVerent> isn't it normally called ALAC?
[15:02] <ubitux> mpeg-4 als is something else afaik
[15:03] <ubitux> maybe you can put some alac in mp4 indeed
[15:03] <Aziroshin> I hope gentoo offers a USE flag to make ffmpeg disable the --strict stuff by default.
[15:03] <ubitux> (or maybe just in the mov variant)
[15:03] <divVerent> 15:03:02         @ubitux | maybe you can put some alac in mp4 indeed
[15:03] <ubitux> Aziroshin: i'm not sure you can remove this at built time
[15:03] <divVerent> I am pretty sure you can
[15:03] <divVerent> given ALAC audio files are called .m4a
[15:03] <divVerent> and use MP4 containers
[15:04] <Aziroshin> It's transcoding now. :)
[15:04] <divVerent> 15:03:09       Aziroshin | I hope gentoo offers a USE flag to make ffmpeg disable the --strict stuff by default.
[15:04] <divVerent> Aziroshin: why?
[15:04] <divVerent> alias ffmpeg="ffmpeg -strict -2"
[15:04] <divVerent> ;)
[15:04] <divVerent> does such stuff really HAVE to be compile time?
[15:04] <Aziroshin> divVerent: Or that. XD
[15:05] <ubitux> divVerent: it seems i can with mp4
[15:05] <ubitux> but i can with mov
[15:05] <divVerent> you can but you can?
[15:05] <ubitux> can't with mp4 sorry
[15:05] <ubitux> ./ffmpeg -f lavfi -i 'testsrc[out0]; aevalsrc=sin(2*PI*t*440)[out1]' -map 0 -t 5 -c:a alac out.mp4  no ok
[15:05] <ubitux> ./ffmpeg -f lavfi -i 'testsrc[out0]; aevalsrc=sin(2*PI*t*440)[out1]' -map 0 -t 5 -c:a alac out.mov  ok
[15:05] <divVerent> ah, then ffmpeg probably lacks it :P
[15:05] <divVerent> because, Apple does produce such m4a files
[15:05] <divVerent> on iTunes e.g.
[15:05] <ubitux> are you sure they haven't not the mov signature?
[15:05] <Aziroshin> Do you think transcoding from flac to aac will cause recognizable quality loss?
[15:06] <divVerent> I can check
[15:06] <ubitux> i've a problem with negation today.
[15:06] <divVerent> don't have any here, though.. damn
[15:06] <divVerent> maybe on the server...
[15:06] <Aziroshin> Because if that's the case, I'll encode from the original wav file and mux the streams together from scratch.
[15:07] <divVerent> how do I see what signature it has?
[15:07] <divVerent>     compatible_brands: M4A mp42isom
[15:07] <divVerent> is this enough?
[15:07] <ubitux> hexdump the top of the file
[15:07] <divVerent> 0000000: 0000 0020 6674 7970 4d34 4120 0000 0000  ... ftypM4A ....
[15:07] <divVerent> 0000010: 4d34 4120 6d70 3432 6973 6f6d 0000 0000  M4A mp42isom....
[15:07] <divVerent> 0000020: 0009 e2c0 6d6f 6f76 0000 006c 6d76 6864  ....moov...lmvhd
[15:07] <divVerent> 0000030: 0000 0000 c8b4 3d9a c8b4 43bd 0000 ac44  ......=...C....D
[15:07] <ubitux> ftypM4A ok
[15:08] <ubitux> "m4a " is audio only
[15:08] <divVerent> well, it is an audio only file
[15:08] <ubitux> but well, mp42 isom is in as well..
[15:09] <divVerent> wonder if MP4Box will allow muxing it with video...
[15:10] <divVerent> hm...
[15:10] <divVerent> IsoMedia import - skipping track ID 1 (unknown type 'alac')
[15:10] <divVerent> that is a problem
[15:16] <divVerent> ubitux: we don't need no non-negations
[15:16] <ubitux> :D
[15:16] <divVerent> we ain't not need no non-negations
[15:17] <divVerent> ain't is my favorite, as it may or may not be negative :P
[15:17] <Aziroshin> Somehow, youtube doesn't eat my mp4 file.
[15:17] <Aziroshin> I transmuxed it from mkv to mp4, and it still doesn't eat it.
[15:18] <Aziroshin> It's h264 and aac.
[15:19] <divVerent> ubitux: is there a "secret hack" to enable a buffer for seeking in ffplay?
[15:19] <divVerent> like what mplayer does when streaming from network
[15:19] <divVerent> it then keeps some stuff buffered so you can seek back for about 20 sec
[15:20] <ubitux> no idea
[15:20] <divVerent> asking, as I wanted to use a complex filter (multiple sources) with ffplay
[15:20] <divVerent> but that seems to simply not be possible
[15:20] <Aziroshin> When I do ffmpeg -i <file> and it shows me: "Aziroshin's Mhykol Mines "Temp" Server Diary, Episode V: The Woodhenge.mp4: Invalid data found when processing input", something's odd, yes?
[15:20] <divVerent> so I wanted to do the filtering in ffmpeg, and ffplay from stdin
[15:21] <divVerent> ffplay only connects [in] and [out]
[15:22] <divVerent> alternative would be using the movie= source
[15:23] <divVerent> catch with that source is that it sucks :P
[15:23] <divVerent> seriously, how does one even specify a file name with it if it contains evil characters
[15:30] <dTal> divVerent: you escape it
[15:31] <dTal> put a backslash in front of every asphanumeric character
[15:31] <dTal> *non-alphanumeric
[15:34] <dTal> that's bash by the way not ffmpeg
[15:43] <thegeek> I'm getting sse2 crashes in libresample in my own mingw build of ffmpeg 1.0 but I can not reproduce in zeranoe's builds; has anyone seen similar problems?
[15:44] <thegeek> I noticed that I used gcc 4.7.0 while zeranoe use 4.7.1 so I'm updating my gcc
[15:44] <thegeek> anything else I should try?
[15:46] <divVerent> dTal: ah, ok
[15:46] <divVerent> but that's useless, can't seek when using the lavfi source
[17:50] <hendry> is there a more efficient codec than ffvhuff for creating a "lossless raw" ?
[17:50] <durandal_1707> efficient in what sense?
[17:51] <Tjoppen> ffv1
[17:52] <hendry> durandal_1707: hd space? i only have a 2G /tmp
[17:52] <hendry> and it fills up in 20 seconds or so
[17:59] <RunawayDevil> My God, why is so fucking hard to make a damn dvd on mac
[17:59] <RunawayDevil> whyyyy whyyyyyyyyyyyyyyyyyy
[18:01] <Tjoppen> hendry: HDDs are $.05 c/GB..
[18:01] <Tjoppen> -c
[18:06] <RunawayDevil> ahhh
[18:06] <Tjoppen> or you a lossy codec at high enough quality
[18:07] <RunawayDevil> why when I convert anyfile to .vob, using mpeg2video codec in extremaly high definition is fast and when i do the same to .mp4 using h.264 it takes almost 10 hours?
[18:07] <RunawayDevil> someone can explain me this?
[18:08] <Tjoppen> because mpeg-2 is a simpler codec
[18:08] <Tjoppen> you can tell x264 to be faster
[18:08] <RunawayDevil> but there is too much difference in the gain of quality that justify my loss of time making a h.264?
[18:09] <Tjoppen> try one of the faster x264 presets and judge for yourself
[18:09] <RunawayDevil> i wanna make a simple dvd with good resolution to watch
[18:09] <RunawayDevil> tell me your opinion please
[18:09] <Tjoppen> DVD = MPEG-2
[18:09] <RunawayDevil> hum
[18:09] <RunawayDevil> h.264 = blu ray
[18:09] <Tjoppen> yes
[18:10] <hendry> hmmm. new problem: x264 [error]: baseline profile doesn't support 4:4:4
[18:10] <durandal_1707> it is self explanatory
[18:11] <RunawayDevil> Tjoppen dvd hd uses which codec?
[18:11] <Tjoppen> hendry: -pix_fmt yuv422p
[18:11] <RunawayDevil> which what ahhh im losting my mind lol
[18:13] <RunawayDevil> I had some bad issues with conversion and burning in macOS, the first one was with the subtitles. I used iFFmepg instead ffmpegx because I could change the size of the fonts and stuff like that... I read in some forums maybe teh problem is with mencoder
[18:15] <RunawayDevil> well, I'm very fedup, now using iFFmpeg (that i bought) I still can change the size of subtitle without shit in the grammar and accents, the app works but not so good too, when I convert to .vob the app automaticaly convert my .srt to .ass and thats the problem... after this better do not edit, or it will be a shit!
[18:18] <thegeek> Is it possible to get a "crossfade" effect when joining two video clips ? (I'm using the concat video filter atm)
[18:18] <RunawayDevil> Tjoppen I will burn a DVD DL, suggest me the codec to make some DVD HD and fill this dvd, pls
[18:22] <Tjoppen> "To record moving pictures, DVD-Video uses either MPEG-2 compression at up to 9.8 Mbit/s (9,800 kbit/s) or MPEG-1 compression at up to 1.856 Mbit/s (1,856 kbit/s)."
[18:23] <Tjoppen> I don't see how you have any choice (unless you want to use uber-crap mpeg-1)
[18:24] <hendry> why is mp4 so much smaller than webm? e.g. http://r2d2.webconverger.org/2012-10-24/
[18:24] <hendry> also why is mp4 preferred by chrome over webm... #confused
[18:29] <Tjoppen> that depends on your encoder settings
[18:29] <Tjoppen> (hashtags don't work on IRC)
[18:30] <hendry> Tjoppen: do these settings look OK? https://github.com/kaihendry/recordmydesktop2.0/blob/master/r2d2.sh#L46
[18:31] <Tjoppen> the webm file has crappy I-frames too
[18:31] <Tjoppen> anyway, libx264 is still a much better encoder than libvpx
[18:32] <Tjoppen> try using -crf with libx264 if you can
[18:33] <hendry> Tjoppen: why? and which value should I use?
[18:33] <RunawayDevil> "ScriptType: v4.00+" this is fucking me? what is this? is this something from libass?
[18:33] <hendry> ffmpeg manpage sez crf "VPX_CQ", "VP8E_SET_CQ_LEVEL"
[18:33] <Tjoppen> why? because
[18:34] <Tjoppen> vpx has -crf too now? hum
[18:34] <Tjoppen> I usually use something between 20 and 24
[18:34] <Tjoppen> lower is better
[18:34] <hendry> i'm pretty happy with mp4 quality and size
[18:35] <Tjoppen> fair enough. I suppose give -crf 24 a try with libvpx and see what happens? I have no idea
[18:36] <RunawayDevil> "ScriptType: v4.00+" this is fucking me? what is this? is this something from libass?
[18:41] Action: hendry wonders why the ffmpeg manpage only refers to -crf in context of VP8
[18:45] <hendry> Tjoppen: -crf 24 on the webm line has made the end file size closer to the mp4!
[18:49] <cbsrobot> RunawayDevil: what are you ranting ?
[18:49] <cbsrobot> what do you want to do ?
[18:50] <cbsrobot> (please the simple answer)
[18:50] <RunawayDevil> cbsrobot I want to burn a DVD with subtitles bigger because the default I can't read
[18:50] <cbsrobot> hardsubs ?
[18:50] <RunawayDevil> yes
[18:51] <RunawayDevil> because soft is not supported in .vob
[18:51] <cbsrobot> so you have a srt file ?
[18:51] <RunawayDevil> yes
[18:51] <cbsrobot> so:
[18:51] <cbsrobot> ffmpeg -i file.srt file.ass
[18:51] <cbsrobot> and then
[18:52] <cbsrobot> what tool do you use for authoring ?
[18:52] <RunawayDevil> iFFmpeg
[18:52] <RunawayDevil> it converts automaticaly the .srt to .ass
[18:52] <cbsrobot> nah
[18:52] <cbsrobot> dvd authoring ?
[18:53] <RunawayDevil> iSkysoft iMedia
[18:53] <RunawayDevil> I noob, kind lost lol
[18:54] <cbsrobot> what tool do you use to create the dvd structure you burn to a dvd ?
[18:54] <cbsrobot> DVD Studio Pro ?
[18:54] <cbsrobot> dvd-author ?
[18:54] <cbsrobot> iDVD ?
[18:54] <Tjoppen> hendry: woo
[18:55] <RunawayDevil> cbsrobot: http://www.iskysoft.com/imedia-converter-deluxe-mac.html
[18:56] <cbsrobot> ah sorry
[18:56] <cbsrobot> I just read ripping
[18:56] <RunawayDevil> cbsrobot: before I used the iFFmpeg I convert to .vob and so .iso and so burn
[18:57] <cbsrobot> what is your input file ?
[18:57] <cbsrobot> vob ?
[18:58] <RunawayDevil> cbsrobot: yes, if you can suggest me something better
[18:58] <RunawayDevil> anyway keep telling
[18:58] <cbsrobot> nah - take the native one
[18:58] <cbsrobot> so now with the ass filei nplace
[18:58] <cbsrobot> can you try:
[18:59] <RunawayDevil> hum
[18:59] <cbsrobot> ffmpeg -i input.vob -vf ass=sub.ass -c:v mpeg2video -sameq -c:a copy output.vob
[19:01] Action: cbsrobot points JEEB to a (maybe) sane usage of sameq &. ^
[19:01] <relaxed> it doesn't work
[19:01] <RunawayDevil> cbsrobot what does it do?
[19:01] <cbsrobot> relaxed: what doesnt work ?
[19:01] <relaxed> -sameq
[19:02] <durandal_1707> sameq does nothing with latest version
[19:02] <cbsrobot> in his version of ffmpeg maybe it still does
[19:02] <relaxed> it was completely removed from libav for that very reason.
[19:02] <durandal_1707> cbsrobot: sameq is broken several years
[19:02] <cbsrobot> and its from mpeg2 -> mpeg2
[19:02] <cbsrobot> so it should work
[19:02] <cbsrobot> well RunawayDevil then try:
[19:03] <durandal_1707> just set very small quant to keep some quality
[19:03] <Ganymede> General question about video (not ffmpeg-specific), does anyone know a tool to graphical tool to losslessly cut H.264 MP4s? mkvmerge does it (into MKV, which is fine) but is not graphical. I tried using avidemux2 to get the timestamps visually and then use mkvmerge but the timestamps from avidemux2 appear to be inaccurate for H.264 (the reported timestamp is x seconds slow for every minute of video and I
[19:03] <Ganymede> don't know the exact formula).
[19:04] <relaxed> MP4Box
[19:04] <RunawayDevil> just a second
[19:04] <cbsrobot> ffmpeg -i input.vob -vf ass=sub.ass -target pal-dvd -quant 3 output.vob
[19:04] <relaxed> Ganymede: oh, with a gui I don't know.
[19:06] <Ganymede> Or the GUI tool can be separate from the actual cutting tool, I just need accurate timestamps. My current process is to do a first draft cut using avidemux2's timestamps and then watch the resulting videos and get an offset for each and cut again.
[19:06] <Ganymede> Very prone to error.
[19:06] <relaxed> I believe you're only going to be able to cut at keyframes.
[19:07] <Ganymede> That's fine. But when the video lags by 40 seconds after an hour, finding the timestamp for the keyframe is still hard (and mkvmerge as far as I can tell, only accepts timestamps for cutting, not frame numbers).
[19:08] <relaxed> You could encode using a lossless, intra only codec
[19:09] <RunawayDevil> cbsrobot what size of subtitle do you consider the best one?
[19:10] <relaxed> That would allow frame accurate cutting using a gui. (if it supports the lossless codec)
[19:10] <RunawayDevil> or anyone else if can tell me
[19:13] <Ganymede> Maybe if I encode the H.264 to DivX or anything, I can get avidemux2 to give me accurate timestamps... (I had a feeling the issue was variable frame rate in H.264? Does that exist?)
[19:17] <brontosaurusrex> Ganymede: it does, handbrake is happy defaulting to that i think
[19:27] <Ganymede> Damn...various factors are preventing me from doing an intermediate encode...guess I'll be stuck with my old workflow.
[20:27] <mbradshaw> Hi all, I have a question with using avfilter through the C API. I'm using avfilter to rescale video (and convert it to the right pixel format) and convert audio (to the right sample format, sample rate, and channel_layout) (I'm also buffering audio using asetnsamples to fill frames with a consistent number of samples)
[20:29] <mbradshaw> If the source audio stream changes (i.e. sample rate, sample format, channel_layout), or if the source video stream changes (width, height, or pixel format), do I have to completely destroy and rebuild the filter graph? Or is there a way to "update" the source filters to the new formats and update (without destroying) the filter graph?
[20:46] <llogan> mbradshaw: we don't get many API answers here.
[20:49] <mbradshaw> llogan: Well, I guess I'll try the mailing list then. Thanks.
[20:49] <cbsrobot> RunawayDevil: still lurking around ?
[20:49] <cbsrobot> sorry I was afk
[20:50] <cbsrobot> did you finish your dvd ?
[20:51] <cbsrobot> RunawayDevil: for DVD I'd say 20px + for reading
[23:09] <VooDooNOFX_> Is is possible to extract a sequence of frames from a prores QT and rewrap it into a new QT of the same params without any conversions using ffmpeg-0.[10|11]?
[23:13] <Tjoppen> ffmpeg -i foo.mov -ss <start time> -t <duration> -vcodec copy bar.mov
[23:13] <Tjoppen> possibly -i after -t
[23:14] <VooDooNOFX_> of course, the copy vcodec. I'll give that a try. thanks
[23:23] <buhman> so if one was to take some arbitrary audio samples, and encode them non-losslessly, take the result, and encode it again, I wonder how many recursions would be required to lose 100% fidelity.
[23:26] <Tjoppen> that depends on the codec. you might just hit a fixed point
[23:26] <Tjoppen> it'd be fairly easy to test. just write a small shell script that uses say libmp3lame to encode one file to 1.mp3, that to 2.mp3, to 3.mp3 etc
[23:27] <Tjoppen> do the same with mp2, aac, vorbis and so on
[23:43] <Endorgh> hi everyone
[23:46] <Endorgh> Is there any way to feed Icecast server with ffmpeg? Or in other words, Is there any way to use ffmpeg to stream audio to icecast?
[00:00] --- Wed Oct 24 2012