[Ffmpeg-devel-irc] ffmpeg.log.20130421

[burek]

[00:07] <brontosaurusrex> so is there something to show me how many consecutive 0 dB samples there was at specific point in time?
[00:32] <Fjorgynn> Good night
[02:57] <THoRIX_> hi, if you are decoding a video using FF_THREAD_FRAME - do you need to subtract (thread_count * single frame delay) in order to generate the correct pts?
[03:16] <Plorkyeran> you do have to compensate for the delay from frame threading yourself
[03:16] <Plorkyeran> but that is unlikely to be a correct way to do it
[03:35] <defaultro1> good evening folks, I would like to convert a .flac to mp3 with the same quality as possible. What would be the parameters?
[03:43] <defaultro1> is 320k highest bitrate for audio?
[03:49] <THoRIX_> Plorkyeran: what would be the right way to do it?
[03:55] <THoRIX_> i tried subtracting ((thread_count-1) * 1.0 / fps) and it seems to fix the incorrect pts issue.  And what i mean by this is when i subtract this constant (when thread_count > 1 - e.g. multi-core machines), my player starts spitting out identical pts to when the player's affinity is set to a single logical core.
[05:47] <roboman2444> so, i am trying to stream yuv420i video and raw pcm audio through pipes to ffmpeg
[05:48] <roboman2444> how should i set up the command? i have been trying a while and keep getting Ignoring attempt to set invalid timebase for st:0
[07:46] <cryptopsy> how to remove this clicking? http://www.filedropper.com/clicking
[07:46] <cryptopsy> i tried the click removal in audacity too, it didn't work
[07:46] <cryptopsy> file is 10 second mp3
[11:09] <jacobs1> hi, how can I configure mpeg4 to do fast encoding ( like x264 ultrafast ) ?
[11:22] <cryptopsy> how to force a video that goes to youtube to stay 1080p quality (at least for the audio) - resize to a high resolution before uploading?
[11:22] <cryptopsy> my command for mp3 to avi is $FFMPEG -loop 1 -i $1 -i $2 -vcodec mpeg4 -threads 4 -acodec copy -y -t $TIME $3
[11:22] <cryptopsy> my mp3's are 320k, but when uploading to yt video is in 360p, which makes the audio less than that
[11:22] <cryptopsy> there are two -i because one is just a picture
[11:24] <cryptopsy> should i uxe x264 instead of mp4 ?
[11:24] <cryptopsy> ah i needed -s hd1080
[11:24] <cryptopsy> thanks
[11:24] <LithosLaptop|2> Youtube determines what bitrate to use based on the resolution of the input video
[11:24] <cryptopsy> LithosLaptop|2: tnx
[11:24] <cryptopsy> fucking jews
[11:25] <LithosLaptop|2> :)
[11:25] <cryptopsy> LithosLaptop|2: does that work with mp4 or do i need to use libx264?
[11:27] <cryptopsy> what does -vpre do? can't find it in ffmpeg manpage
[11:29] <LithosLaptop|2> works with anything
[11:30] <LithosLaptop|2> youtube will still transcode the audio
[11:31] <cryptopsy> File Preset for max not found when doing -vpre=max
[11:31] <LithosLaptop|2> but at a higher resolution video (720p/1080p), youtube will use a higher bitrate for audio than what it would of used for 360p input
[11:31] <cryptopsy> what's this file preset error, i get it for 'hq' too
[11:32] <cryptopsy> is -vpre deprecated?
[11:32] <LithosLaptop|2> I don't know
[11:33] <LithosLaptop|2> maybe somebody else here could help
[11:38] <cryptopsy> LithosLaptop|2: had i known your advice month ago, wouldnt have to transcode over 40 albums and reupload it all
[11:39] <LithosLaptop|2> ffmpeg -loop 1 -i 720p.png -i test.mp3 -shortest -c:v libx264 -c:a copy -r 24000/1001 -profile:v baseline -pix_fmt yuv420p -crf 18 testing.mkv
[11:39] <LithosLaptop|2> thats what I used once
[11:39] <LithosLaptop|2> just make sure that 720p.png is 1280x720 or 1920x1080
[11:41] <cryptopsy> that's not practical
[11:42] <cryptopsy> use -s hd1080
[11:43] <LithosLaptop|2> well I didn't want to resize a 360p image to 1080p :)
[11:45] <LithosLaptop|2> anyway the best would be to upload raw pcm instead of 320kbps MP3s and let youtube encode the audio only once, but that will take a long time to upload
[11:45] <LithosLaptop|2> FLAC doesn't work :(
[11:51] <cryptopsy> you're right, gonna put that on my todo lists
[11:51] <cryptopsy> i usually upload from university
[11:51] <cryptopsy> so download r fast
[11:51] <cryptopsy> uploads*
[11:52] <cryptopsy> do you kno whow to upload to yt from the command line?
[11:53] <cryptopsy> there's a youtube-dl and a youtube-upload but youtube-upload isn't in the gentoo tree
[11:53] <cryptopsy> even though the'yre made by the same software writer
[11:57] <cryptopsy> LithosLaptop|2:  i met a guy in amsterdam who was uploading full albums in flac every 3 minutes
[11:58] <cryptopsy> almost 24/7
[11:58] <cryptopsy> LithosLaptop|2: going to sleep, peace out
[11:58] <LithosLaptop|2> hmm, I guess he knows something that I don't
[11:58] <saste> yes, for example the name of his own pet
[11:58] <LithosLaptop|2> haha
[14:12] <_julian> hi
[14:12] <_julian> is there a way to flush data that was read by avformat_find_stream_info?
[14:13] <_julian> actually when playing live streams I would prefer to skip some data at start instead of having a bigger delay
[16:30] <g0dfrey> I'm going to write a small web-controled-only player. Which lib do i need to learn? Or is there any simple api usage examples?
[16:47] <xlinkz0> i have yet to find something simple about api usage
[17:40] <lnd7> anyone know how to escape the path to the font correctly (win7 .bat). tried a lot of different things but couldn't get it to work:
[17:40] <lnd7> C:\video\ffmpeg -i video.avi -vf "scale=iw/5.35:-1,drawtext=fontfile="C:\Windows\Fonts\Arial.ttf":Fonts: timecode='00\:00\:00\.00': rate=30000/1001: x=(w-tw)/2: y=h-(1.5*lh): fontcolor=white: box=1: boxcolor=0x00000000 at 1" temp_ss_%%06d.jpg
[17:49] <lnd7> ah got it, nvm
[18:41] <xebra> hi, does anybody know how to convert a video from one framerate to another? Is it even possible with ffmpeg? (since I see several people online complain it doesn't work)
[18:42] <xebra> the -r option doesn't seem to work well. I have a video at 1fps, I want to change it to 24fps without changing the speed
[18:44] <xebra> and sometimes it seems to work, but it's "fake", which means I get 24fps reported by one player, but in reality it's still 1fps when imported in a video editor like blender for example
[18:47] <LithosLaptop> -r should work
[18:51] <brontosaurusrex> xebra, most video editors have "interpret footage" thingy hidden somewhere
[18:54] <divVerent> xebra: how do you want it converted
[18:54] <divVerent> by duplicating each frame 24 times?
[18:59] <xebra> divVerent, I guess so.
[19:09] <xebra> I just checked with blender, it's so weird. I converted the video this way: ffmpeg video.mp4 -vcodec libx264 -vpre default -b 3000k -s 1280x720 -r 24 temp.mp4 ...well, the ubuntu movie player (gstreamer?) reports it to be 24fps, but vlc says it's still 1fps, and in blender it's treated like it's 6fps or so
[19:10] <xebra> and if I'm not mistaken, youtube also converts 1fps videos to 6fps when you upload them
[19:21] <xebra> however, I just tried to export that same video with blender, at 24fps (but accelerated), and the output REALLY is at 24fps then. Doesn't blender use ffmpeg to export in h264? If so, then it should also be possible to do this directly from ffmpeg, but I don't seem to be able to
[19:24] <brontosaurusrex> maybe ffmpeg -r 1 video.mp4 -vcodec libx264 -vpre default -b 3000k -s 1280x720 -r 24 temp.mp4
[19:35] <xebra> brontosaurusrex, I think I've tried that... but with an additional -i in front of video.mp4
[19:36] <xebra> now I'm tring to check what blender does when it exports a video, reading the messages in the console, what parameters it uses
[19:57] <xebra> I don't see anything there that even mentions frame rate. I guess blender encodes starting from a totally different format (frames are images) and that's why it works, while if I use ffmpeg directly it doesn't
[19:57] <xebra> maybe the solution at this point is to use pipelining...
[20:30] <xebra> it's a problem with mp4 though. If I output the file in avi, -r 24 works normally
[20:30] <xebra> I wonder why
[21:48] <knhalp> I know about the concat: thing in order to join videos of the same type, but is there a way to reliably join any format/encoding of video together as long as the resolution is the same?
[21:49] <knhalp> Or will I need to uncompress it before sticking it into a container
[21:52] <ubitux> knhalp: https://www.ffmpeg.org/faq.html#How-can-I-join-video-files_003f
[21:53] <ubitux> you might be looking for the concat demuxer
[21:55] <knhalp> woah what
[21:55] <knhalp> certificate error on ffmpeg domain
[21:55] <knhalp> It's fine but, strange
[21:56] <knhalp> ubitux: I love you. this is EXACTLY what I want. Will it 'demux' any video file? Like a FRAPS AVI or an X264 MKV
[21:57] <ubitux> it should
[21:57] <knhalp> And (Sorry to keep bothering) how does it handle videos with different framerates and resolutions?
[21:57] <knhalp> I don't need it to handle other resolutions, but differing framerates might be useful
[21:58] <ubitux> it doesn't care about frame rate but timestamps; and that should be explained in the demuxer documentation (http://www.ffmpeg.org/ffmpeg-formats.html#concat)
[21:59] <knhalp> Thank you
[21:59] <brontosaurusrex> so is it possible to compile ffmpeg with x11_grab statically?
[22:03] <brontosaurusrex> relaxed, do you have your static-build commands handy?
[22:03] <brontosaurusrex> i need x264, fdk-aac and x11_grab (if possible) version
[00:00] --- Mon Apr 22 2013