[Ffmpeg-devel-irc] ffmpeg.log.20120330

[burek]

[00:15] <rschmidt> hi guys, I've got a bit of a strange situation while trying to read from a capture device with a freshly-built ffmpeg
[00:16] <rschmidt> I'm trying to read from a Hauppauge HD PVR in linux, and convert that to an FLV(h264+aac or mp3 audio) for Flash
[00:17] <rschmidt> when I pass the video source (/dev/video0) to ffmpeg with -i, it encodes a few frames (typically between 100 and 200) and it hangs there... doesn't respond to keyboard input
[00:17] <rschmidt> doesn't crash either, though
[00:18] <rschmidt> and if I cat the contents of /dev/video0 and read them in ffmpeg through stdin, it keeps on chugging with no hang
[00:18] <rschmidt> so it's not a big problem per se, but it is a bit odd that doing things the 'right' way hangs and the roundabout way works.
[03:31] <Kittens> oh dear where do I start.
[03:33] <Kittens> I own a copy of wirecast and have been using justin/twitch.tv as my streaming service for about a year or two. yesterday they suspended my account because I took my medication on camera and that constituted "illegal drug use." I would like to run a stream from my own server (which has plenty of bandwidth to spare) and someone told me that ffserver would be the best choice. (server runs archlinux)
[03:39] <Kittens> this is the error I keep getting [tcp @ 0x246e180] TCP connection to localhost:8090 failed: Connection refused
[08:29] <burek> Kittens,
[08:29] <burek> can you please use pastebin.com, to show your command line and its output?
[08:30] <burek> moses1, you too?
[08:32] <moses1> hi kittens, surely, but i have to leave the office right now
[08:32] <moses1> so you later
[08:33] <burek> ok :)
[09:08] <rsv> if i want to convert yuv422 to rgb888 which function i have to use to do it
[10:29] <lahwran> hi. I'd like to resample a 11025hz sound file to 44100hz, because I want to play it on a device that doesn't like 11025hz
[10:30] <Tjoppen> ffmpeg -i foo.wav -ar 44100 bar.wav
[10:31] <lahwran> !
[10:31] <lahwran> how nice and easy :D
[10:31] <lahwran> Tjoppen: thanks!
[10:34] <Tjoppen> :)
[12:33] <brontosaurusrex> how can i overlay an alpha-rich png still over first 8 seconds of my video?
[13:38] <filo1234> hi all, for extract audio from an flv video is it a good choise? ffmpeg -i input.flv -acodec mp3 -ab 192k out.mp3
[13:45] <filo1234> or there is some other options to add?
[13:46] <moses> @burek
[13:55] <zimnyx> I've encoded a movie using xvidcap (codec=FFMpeg MPEG-4), its size is 45MB. When I bzip2 it, its size falls down to 25MB. Is it fine? I mean shouldn't MPEG be maximaly compressed?
[14:17] <brontosaurusrex> filo1234: flv audio could be mp3 allready, so you just need to demux
[14:19] <brontosaurusrex> filo1234: your example is transcoding from lossy to lossy
[14:19] <filo1234> brontosaurusrex: so what you could to be use for?
[14:19] <filo1234> which string
[14:20] <filo1234> brontosaurusrex: simply ffmpeg -i input.flv out.mp3?
[14:20] <brontosaurusrex> ffmpeg -i in.flv -acodec copy out.mp3 maybe
[14:21] <filo1234> brontosaurusrex: but if I want to set best quality audio like ab 190k?
[14:21] <filo1234> -ab*
[14:23] <brontosaurusrex> filo1234: you cant get any better than it allready is, so the goal is to keep it equaly small
[14:23] <filo1234> brontosaurusrex: ok thanks a lot
[14:23] <filo1234> I'm not very expert about audio/video :| like you can see lol
[14:24] <brontosaurusrex> how can i overlay an alpha-rich png still over first 8 seconds of my video?
[14:56] <globus> Does any one know how to use the rtpenc.c file ?
[17:23] <madwill> Anybody feels all mighty on this friday and would like to throw a compiled x264 lib in 64 bit this way for a poor mans that can't get it to work
[17:23] <madwill> I can only build 32 bit for some reason
[17:25] <burek> why?
[17:26] <madwill> Currently : DIED: endian test failed
[17:26] <madwill> I have no idea what i means
[17:26] <burek> did you try google?
[17:28] <burek> I tried and this is what I've found
[17:28] <burek> http://www.linuxquestions.org/questions/linux-newbie-8/config-error-729725/
[17:28] <burek> "Then I guess, the problems are solved ... the "endian test failed", error origins from a missing package 'glibc-headers' ."
[17:28] <burek> do you have build tools installed? (gcc, make, ...)
[17:29] <burek> if not: apt-get install build-essentials
[17:29] <madwill> Oh! good idea, i'M building it on my windows machine but i should build it on a linux one
[17:29] <burek> build-essential*
[17:30] <burek> well you can build it on a Windows machine too, but you need build tools too :)
[17:30] <madwill> I do have them,
[17:30] <madwill> gcc and minGW the 32 bit build work flawlessly
[17:30] <madwill> but i need the 64 as well
[17:31] <madwill> can't link dynamic shared lib with a 64 bit process
[17:31] <burek> hm, I'm weak at cross-compiling, so you might wait for someone more experienced to come on irc
[17:32] <madwill> i'm simply going to try on linux
[17:33] <burek> ok :)
[17:35] <madwill> Thanks :P
[17:36] <burek> :beer: :)
[17:41] <madwill> Haha same error i must be simply getting the command wrong
[17:42] <madwill> Used this : ./configure --cross-prefix=x86_64-w64-mingw32- --host=x86_64-pc-mingw32
[17:43] <burek> try configure --help | less
[17:43] <burek> :)
[18:34] <Diogo> hi one question..
[18:34] <Diogo> Unrecognized option 'directpred' anyone know what this it?
[18:35] <burek> can you please use pastebin.com, to show your command line and its output?
[18:40] <Diogo>  http://pastebin.com/qxSqFhNz
[18:41] <burek> oh
[18:41] <burek> vpre is deprecated
[18:41] <burek> ffmpeg now uses native x264's -preset -tune and -profile
[18:41] <burek> try typing x264 --help
[18:42] <burek> and see presets/tunes/profiles
[18:43] <burek> after that use: ffmpeg ... -preset .. -profile ... -tune ... (which ever you need or all of them)
[19:41] <Diogo> where i can find the last ffmpeg preset?
[19:49] <burek> Diogo, there are no
[19:49] <burek> its deprecated
[19:49] <burek> ffmpeg now uses x264's native presets/profiles/tunes
[19:49] <burek> type x264 --help
[19:50] <burek> meaning, after you specify -vcodec libx264 you can use all the x264's options: http://mewiki.project357.com/wiki/X264_Settings
[19:51] <burek> for example: ffmpeg -i input.avi -vcodec libx264 -preset fast -tune film -crf 20 ...
[21:50] <Kakadu> hallo!
[21:51] <Kakadu> I have a video a.flv (h264/aac) and I want to copy part from this video to another file with the same codecs.
[21:52] <Kakadu> I write `ffmpeg -ss 01:02:08 -t 00:52:20 -acodec copy -vcodec copy -i a.flv 1.flv` but ffmpeg doesn't understand that I want copy codecs
[21:52] <Kakadu> (I've found example with `copy` here: http://blog.yimingliu.com/2008/10/07/ffmpeg-encoding-gotchas/ )
[21:53] <burek> can you please use pastebin.com, to show your command line and its output?
[21:54] <Kakadu> burek: http://paste.in.ua/4089/
[21:55] <burek> built on Feb 14 2012
[21:55] <burek> are you serious? :)
[21:55] <Kakadu> debian unstable
[21:55] <burek> oh my bad :)
[21:55] <burek> sorry :)
[21:55] <Kakadu> :)
[21:56] <burek> -i
[21:56] <burek> goes before
[21:56] <burek> -acodec and -vcodec
[21:56] <burek> parameters order do matter
[21:56] <Kakadu> I should swap parameters?
[21:56] <Kakadu> ok...
[21:56] <burek> try something like this
[21:56] <burek> ffmpeg -ss 01:02:08 -i live_user_sc2tv_ru_1331297204.flv -acodec copy -vcodec copy -t 00:52:20 1.flv
[21:57] <JEEB> generally stuff before -i is related to decoding, while after -i is encoding
[21:57] <burek> if you want to seek after the video is decoded (more accurate) then use this
[21:57] <Kakadu> burek: WoW. Thanks a lot!
[21:57] <burek> ffmpeg -i live_user_sc2tv_ru_1331297204.flv -ss 01:02:08 -acodec copy -vcodec copy -t 00:52:20 1.flv
[21:58] <Kakadu> burek: -ss and -t before -i also works :)
[21:58] <burek> yes I know, but it's a good practice to form a kind of parameters flow
[21:58] <burek> like from input to output
[21:58] <burek> in order what needs to be done
[21:59] <burek> "take the input, seek some time, skip encodings, set the final duration, write to file"
[21:59] <Kakadu> burek: OK, I understand
[23:17] <globus> I am trying a couple of weeks now to use libav* for streaming purposes only. I want to stream over rtp already encoded frames. I encode the frames using the x264-api. Thanks
[23:18] <globus> How can I use the libav* to stream only not to encode ? I have made it to encode and stream over rtp frames using the libav* but now I want to use it only to stream
[23:26] <burek> did you try asking in #libav ?
[23:27] <sacarasc> libav* are the libraries ffmpeg is made up of, burek. :p
[23:27] <burek> just try..
[23:30] <globus> oops sorry
[23:30] <globus> sorry guys
[23:30] <burek> :beer: :)
[23:31] <globus> hahahaha
[23:48] <Lorra> Hi everyone! I am trying to convert a wmv video to an mp4 one and actually the video comes out good, but sound in the output file gets lost. Do you have a quick command line to perform this conversion?
[23:48] <JEEB> -c:a aac -strict experimental -ab 192k
[23:49] <Lorra> (maintaining quality, that is, I think, bitrates, size and audio sampling frequency)
[23:49] <JEEB> this is, in the case ffmpeg can read the audio off that wmv file
[23:49] <Lorra> JEEB, with ffmpeg -i input.wmv in front of that
[23:50] <Lorra> and the name of the output file at the end of it?
[23:50] <JEEB> uhh
[23:50] <Lorra> JEEB, what would the whole command be?
[23:51] <Lorra> JEEB, with input and output files
[23:51] <JEEB> ffmpeg -i input.derp -c:v libx264 -crf 20 -preset:v fast -c:a aac -strict experimental -ab 192k out.mp4
[23:51] <Lorra> what is the -crf?
[23:51] <JEEB> constant rate factor
[23:51] <JEEB> closest we have to "constant quality" in x264
[23:51] <JEEB> if it looks good you can try raising it, if it looks bad you can lower it
[23:52] <Lorra> isn't the number of frames per second mentioned in this command?
[23:52] <JEEB> the idea is to use the highest number that still looks good
[23:52] <JEEB> why would it?
[23:52] <JEEB> in most cases you want the timestamps from input
[23:52] <JEEB> as in, not changing a thing
[23:52] <JEEB> -preset:v sets the libx264 preset
[23:52] <JEEB> http://mewiki.project357.com/wiki/X264_Settings#preset
[23:52] <JEEB> ^ a listing of them
[23:53] <JEEB> slower presets will use techniquest that will help you compress the clip better, faster are meant for cases when compression plays a smaller role for you than speed
[23:54] <JEEB> (everything except for ultrafast and placebo should be usable, placebo is "everything up to eleven" and "ultrafast" is to show that libx264 can be quite fast if needed -- for speed benchmarks)
[23:54] <Lorra> JEEB, it says this: ffmpeg: failed to set value 'libx264' for option 'c:v'
[23:54] <Lorra> I do have the package with that library installed though
[23:55] <JEEB> how old is your ffmpeg?
[23:55] <JEEB> I gave you commands primed for the current ffmpeg HEAD
[23:55] <Lorra> It's 0.7.3
[23:56] <JEEB> then -c:v and -c:a would be -vcodec and -acodec
[23:56] <JEEB> and yes, that's quite an old'ish version
[23:57] <Lorra> and what would preset:v be?
[23:57] <Lorra> ffmpeg: failed to set value 'fast' for option 'preset:v'
[23:57] <Lorra> it's the latest version shipped with Ubuntu 11.10
[23:57] <JEEB> which usually means that it's from around 4-5 months before that :)
[23:58] <JEEB> preset:v probably is -preset
[00:00] --- Sat Mar 31 2012