[Ffmpeg-devel-irc] ffmpeg.log.20120926

[burek]

[01:06] <FelipeS> Hey all, so I'm using ffprobe -show_frames but I'm having trouble understanding the output. For example, what does pkt_duration=3750 mean; what are the units? Also, what about coded_picture_number or display_picture_number?
[01:08] <saste> FelipeS, pkt_duration is expressed in stream timebase units
[01:08] <saste> coded_picture_number: what you don't understand don't hurt you
[01:16] <FelipeS> saste, I need to figure it out. I'm guessing it is the frame number in which it was encoded
[01:16] <FelipeS> but not necessarily saved in that order.
[01:17] <saste> FelipeS, yes
[01:17] <FelipeS> also, why are some pkt_dts=N/A
[01:17] <saste> for more info check avformat.h/avcodec.h
[01:17] <saste> the exposed fields are the same used by the libraries (it's meant to be a thin wrapper)
[01:17] <saste> DTS is not always defined
[01:25] <FelipeS> saste why is it not always defined? I thought it gave the decoder the order in which it should decode the frames
[01:26] <saste> FelipeS, that's a library problem, should investigate there
[01:26] <saste> and i don't think it is always present, depends on the demuxer/format
[01:26] <FelipeS> saste would you recommend a book?
[01:27] <FelipeS> particular*
[01:27] <FelipeS> I'm having trouble collecting info from random sites on the net
[01:27] <saste> FelipeS, what's the problem, specifically?
[01:27] <saste> libav* doxy may be helpful, or source code otherwise
[01:28] <FelipeS> saste oh I thought you were telling me to look it up at a library (book).
[01:29] <FelipeS> I'm just analyzing how apple's segmenter works
[05:27] <FelipeS> So it seems ffprobe used to show the frame size when the -show_frames knob was enable
[05:27] <FelipeS> what happened to it?
[05:45] <FelipeS> anyone?
[06:25] <praveen> hi everyone
[06:26] <praveen> was looking on some info on encoding srt/ass subtitles into HLS
[06:26] <praveen> im streaming to an apple device
[06:28] <praveen> i cant find much documentation on it. can anyone point me to the right command
[10:19] <kendooo> where are the presets for ffmpeg version N-44477-g47277c4   ?
[10:19] <kendooo> sorry i mean the commandline examples
[10:20] <kendooo> why is this not working ffmpeg -y -i demo.wmv -vcodec libx264 -crf 23 -strict experimental -acodec aac -aq 100 -ar 22050 demo.mp4
[10:21] <kendooo> can somebody give me the right commandline for mp4 for this version ffmpeg version N-44477-g47277c4
[11:05] <elisescu> Hi! How can one concatenate two or more mp4 video files without re-encoding them? Or if not possible without re-encoding, how can keep the same format for both audio and video? Thanks!
[12:12] <burek> elisescu, you cant
[12:13] <burek> and
[12:30] <praveen> hi
[12:30] <praveen> can ffmpeg softsub into an mp4 container
[12:30] <praveen> and if so could someone help me out with the command
[12:43] <burek> praveen, with what command
[12:48] <praveen> burek: thats what i want to knwo
[12:48] <burek> what is a softsub
[12:49] <praveen> a softsub is a sub that is not hardcoded into a video
[12:49] <praveen> i can currently do a -vf "ass=subtitle.ass"
[12:49] <burek> i see
[12:49] <praveen> but it will hardcode it into the video. i want to have multiple subtitle streams the user can toggle between
[12:49] <burek> what are your inputs?
[12:49] <burek> can you use ffmpeg -i on your inputs
[12:50] <burek> and use the pastebin
[12:50] <JEEB> mp4 doesn't originally have any subtitle formats supported, but you can put 3gpp timed text there. Not sure if ffmpeg can convert other text-based subtitles to 3gpp timed text tho
[12:51] <praveen> burek: give me a sec
[12:52] <JEEB> I think mp4box can convert srt to 3gpp timed text and mux it into mp4
[12:52] <JEEB> GPAC is a PITA to build tho >_>
[12:52] <burek> http://en.wikipedia.org/wiki/MPEG-4_Part_14
[12:53] <burek> Subtitles: MPEG-4 Timed Text (also known as 3GPP Timed Text).
[12:53] <burek> Nero Digital uses DVD Video subtitles in MP4 files
[12:53] <burek> do you have to use mp4
[12:53] <JEEB> yeah, the 3gpp timed text is the only official'ish thing. Didn't remember it was standardized as MPEG-4 Timed Text too
[12:53] <JEEB> nero's derp isn't official as far as I know
[12:53] <JEEB> just like their derpy chapters
[12:54] <JEEB> https://ffmpeg.org/general.html#Subtitle-Formats
[12:54] <JEEB> 3gpp timed text has an encoder and decoder, but can't be muxed or demuxed?
[12:54] <JEEB> not sure what exactly ffmpeg can do with it :/
[12:55] <praveen> burek http://pastebin.com/02kdxSBt
[12:58] <praveen> burek huh? didnt i do that
[12:58] <burek> you did half of it afaics
[12:59] <praveen> oh
[12:59] <praveen> right
[12:59] <burek> btw, praveen, do you really need to use mp4
[12:59] <burek> can you use mkv or flv or something else?
[13:00] <JEEB> was the format for 3gpp timed text ttxt or something_
[13:00] <JEEB> ?
[13:00] <praveen> burek, well i actually want to stream this via HLS to an iPAD
[13:00] <praveen> or many many ipads
[13:02] <praveen> burek, http://pastebin.com/wtFW4FM6
[13:03] <JEEB> anyways, if ffmpeg can't convert the text of those subtitles into mov_text/ttxt/however it's called, then you could try mp4box >_> its newest version should be able to make files with 3gpp timed text that works with apple devices methinks
[13:04] <JEEB> (you would have to give the subtitles to mp4box in srt form tho)
[13:04] <praveen> JEEB, thats fine
[13:04] <praveen> crap. for some reason that command i give you doesnt hardcode the subs anymore.
[13:05] <praveen> grr... it used to.
[13:05] <burek> praveen, did you try: ffmpeg -i BigBuckBunny.mp4 -i bigbuck.ass -map 0 -map 1 -vcodec libx264 -vprofile main -preset slow -b:v 1024k -maxrate 400k -bufsize 800k -vf scale=-1:480 -threads 0 -acodec libfaac bigbuckbunny_sub.mp4
[13:06] <praveen> dont think so. i can try that now
[13:08] <praveen> burek, it complains "Encoder (codec none) not found for output stream #0:2"
[13:08] <praveen> will pastebin the whole thing
[13:08] <JEEB> yeah
[13:08] <praveen> http://pastebin.com/bGGymeYy
[13:08] <JEEB> so it can't convert anything to timed text
[13:09] <JEEB> you could try adding -scodec mov_text or something, but I have a feeling you'll just get a new error
[13:09] <burek> no, that's related to aac stream
[13:09] <burek> oh, its output
[13:09] <burek> sorry
[13:09] <JEEB> Stream #1:0 -> #0:2 (ass -> ?)
[13:09] <JEEB> yeah
[13:11] <JEEB> I'm pretty sure he'll have to encode with ffmpeg and then mux in the timed text streams with mp4box or something >_>
[13:15] <praveen> actually im not sure whats going on now. i run the same command but i cant get subs to even hardcode into the video
[13:22] <praveen> crap. thanks anyway guys
[13:49] <praveen> i find it very strange that handbrake can do it but not ffmpeg
[13:49] <praveen> is it possible to add multiple streams of subtitles first using handbrake and then segment using ffmpeg
[14:03] <burek> http://www.youtube.com/watch?v=F7pYHN9iC9I :)
[14:15] <ubitux> huh?
[14:15] <ubitux> JEEB: you can mux 3gpp sub into mov
[14:15] <ubitux> -c:s mov_text
[15:51] <ed8> hi, is it possible to use ffmpeg as an on-demand streaming server ?
[20:02] <Pinhole> I'm trying to make the absolute smallest mp4 file possible with a png and a wav as source.  I don't care much about quality.
[20:02] <Pinhole> ffmpeg -loop_input -i 451_16.png -i /home/html/noah/please_thankyou.wav -r 1 -shortest -acodec ac3 test.mp4
[20:06] <llogan> Pinhole: add "-c:v libx264 -crf 51 -preset veryslow -tune stillimage"
[20:06] <llogan> 51 is the "crappiest" quality level
[20:08] <Pinhole> hmmm, I'm still at 1.2M.  Is there a better audio or video codec for this?
[20:14] <relaxed> try aac instead of ac3
[20:47] <llogan> Pinhole: it's hard to tell you an exact encoder name since we don't know what your ffmpeg supports
[20:48] <llogan> (using a pastebin site to show your complete console output of "ffmpeg" would suffice)
[20:49] <tmatth> when playing an SDP containing one RTP stream with ffmpeg, is it possible for the UDP socket to be opened with reuse=1 ?
[20:49] <Pinhole> llogan: http://pastebin.ca/2210666
[21:02] <llogan> Pinhole: the only aac encoder availabe to you is "-acodec aac -strict experimental"
[21:03] <llogan> or you could use libmp3lame. or you could use an external aac encoder to encode the audio and mux the video and audio together with ffmpeg.
[21:13] <Anon62746> :)
[21:26] <FelipeS> is there any way to remove just the audio frames from a leaving the video alone. When I attempt to do this using ffmpeg -i segment0.ts -an -vcodec copy segment0_na.ts the segment's video playback timestamps are modified
[21:27] <FelipeS> *from a video segment
[21:28] <FelipeS> actually "segment0.ts" would be a bad example, because the problem is evident when the segment that I'm trying to process is not the first one
[21:35] <humbolt> when I know the bandwidth of my audio and my video stream, how do I calculate the TS-muxrate? is it calculated by adding the rates of the audio and video streams, or is there some overhead to add? ergo, does the ts-muxrate include mux data or only the payload?
[22:09] <DelphiWorld> yo everyone
[22:09] <DelphiWorld> can H.323 rip youtube?
[22:09] <DelphiWorld> CRAAAAAAP
[22:09] <DelphiWorld> can FFmpeg rip youtube?
[22:15] <ubitux> dump the video with clive
[22:16] <ubitux> then "rip" it as you want.
[22:22] <FelipeS>  is there any way to remove just the audio frames from a leaving the video alone. When I attempt to do this using ffmpeg -i segment3.ts -an -vcodec copy segment2_na.ts the segment's video playback timestamps are modified
[22:24] <Umeaboy> Hi!
[22:25] <Umeaboy> ffmpeg -i then the input name -async 0 output........................ To get the outputfile as mp4 do I have to type anything else as well?
[22:32] <ubitux> why -async 0?
[22:44] <Luis1> Am using the C++ Api and i wonder if there is any way to handle video Blobs(strings) instead of an actual file
[22:46] <ubitux> i don't understand the question
[22:47] <Luis1> i only see samples where the file is loaded from disk
[22:47] <ubitux> you want to load from a pipe?
[22:49] <Luis1> am using the C api but the content resides in memory in a c++ string
[22:49] <Luis1> not in a file
[22:50] <ubitux> yeah maybe using a custom avio_context
[22:52] <Luis1> ok, thnaks
[22:52] <ubitux> that was fast
[00:00] --- Thu Sep 27 2012