[Libav-user] Add subtitles to MKV file

[none elenifan]

I had checked the values about time_base's in AVStream's, and in AVPackets of source and target. Furthermore, the pts, dts in the first two AVPackets, read and write, are both 0 and duration, 999; but I got "00:00:00,000 --> 00:00:00,999" in  source packet and "00:02:11,072 --> 00:02:12,071" in target one.
 
> Date: Sat, 5 Jul 2014 17:40:38 +0200
> From: nfxjfg at googlemail.com
> To: libav-user at ffmpeg.org
> Subject: Re: [Libav-user] Add subtitles to MKV file
> 
> On Sat, 5 Jul 2014 16:15:44 +0800
> "ingmar" <ingmar at kingsoftware.com.tw> wrote:
> 
> > Hello Everyone!
> > 
> >  
> > 
> > I am trying to add some text, being a stream, into an MKV file which has
> > encoded video and audio data already. Because of some reasons, storing the
> > text to an isolated file is not acceptable.
> > 
> >  
> > 
> > The problem I encountered was the times of subtitles were incorrect like
> > below.
> > 
> >  
> > 
> > [Original]
> > 
> > 1
> > 
> > 00:00:00,000 --> 00:00:00,999
> > 
> > 2014-07-01 11:59:28
> > 
> >  
> > 
> > 2
> > 
> > 00:00:01,000 --> 00:00:01,999
> > 
> > 2014-07-01 11:59:29
> > 
> >  
> > 
> > [Encoded]
> > 
> > 1
> > 
> > 00:02:11,072 --> 00:02:12,071
> > 
> > 2014-07-01 11:59:28
> > 
> >  
> > 
> > 2
> > 
> > 00:02:12,072 --> 00:02:13,071
> > 
> > 2014-07-01 11:59:29
> > 
> >  
> > 
> > My approach is following.
> > 
> > 1. Create 3 streams: video, audio and subtitle with code AV_CODEC_ID_SUBRIP
> > and add to the target MKV file.
> > 
> > 2. Encode all video and audio data.
> > 
> > 3. Create a temporary SRT file and store all text in it.
> > 
> > 4. Read a packet from SRT file (av_read_frame) -> decode
> > (avcodec_decode_subtitle2) -> encode (avcodec_encode_subtitle) -> write to
> > MKV file (av_interleaved_write_frame).
> > 
> >  
> > 
> > I have been sure the time_base fields of the input and output streams were
> > the same; and also for the pts, dts and duration ones of the input and
> > output packets.
> > 
> >  
> > 
> > Any advice would be greatly appreciated.
> > 
> 
> Maybe wrong timebase in timestamp calculations? Just guessing.
> _______________________________________________
> Libav-user mailing list
> Libav-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/libav-user
 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://ffmpeg.org/pipermail/libav-user/attachments/20140706/60c51a19/attachment.html>