[FFmpeg-devel] {WIP} {HELP} Dvb Subtitles and Hard Subtitles

Michael Niedermayer michaelni at gmx.at
Sun Jun 12 04:38:09 CEST 2011 

On Sat, Jun 11, 2011 at 12:46:09PM +0100, JULIAN GARDNER wrote:
> 
> 
> 
> 
> ----- Original Message -----
> > From: JULIAN GARDNER <joolzg at btinternet.com>
> > To: FFmpeg development discussions and patches <ffmpeg-devel at ffmpeg.org>
> > Cc: 
> > Sent: Wednesday, 8 June 2011, 8:29
> > Subject: Re: [FFmpeg-devel] {WIP} {HELP} Dvb Subtitles and Hard Subtitles
> > 
> > 
> > 
> > 
> >> ________________________________
> >> From: Michael Niedermayer <michaelni at gmx.at>
> >> To: FFmpeg development discussions and patches 
> > <ffmpeg-devel at ffmpeg.org>
> >> Sent: Wednesday, 8 June 2011, 5:15
> >> Subject: Re: [FFmpeg-devel] {WIP} {HELP} Dvb Subtitles and Hard Subtitles
> >> 
> >> On Tue, Jun 07, 2011 at 11:56:44PM +0100, JULIAN GARDNER wrote:
> >>> 
> >>> 
> >>> 
> >>>  >________________________________
> >>>  >From: JULIAN GARDNER <joolzg at btinternet.com>
> >>>  >To: FFmpeg development discussions and patches 
> > <ffmpeg-devel at ffmpeg.org>
> >>>  >Sent: Tuesday, 7 June 2011, 14:00
> >>>  >Subject: Re: [FFmpeg-devel] {WIP} {HELP} Dvb Subtitles and Hard 
> > Subtitles
> >>>  >
> >>>  >
> >>>  >
> >>>  >
> >>>  >
> >>>  >----- Original Message -----
> >>>  >> From: Michael Niedermayer <michaelni at gmx.at>
> >>>  >> To: FFmpeg development discussions and patches 
> > <ffmpeg-devel at ffmpeg.org>
> >>>  >> Cc: 
> >>>  >> Sent: Monday, 6 June 2011, 13:34
> >>>  >> Subject: Re: [FFmpeg-devel] {WIP} {HELP} Dvb Subtitles and 
> > Hard Subtitles
> >>>  >> 
> >>>  >> On Mon, Jun 06, 2011 at 11:15:32AM +0100, JULIAN GARDNER 
> > wrote:
> >>>  >>> 
> >>>  >>> 
> >>>  >>> 
> >>>  >>>  >________________________________
> >>>  >>>  >From: JULIAN GARDNER <joolzg at btinternet.com>
> >>>  >>>  >To: FFmpeg development discussions and patches 
> >>>  >> <ffmpeg-devel at ffmpeg.org>
> >>>  >>>  >Sent: Sunday, 5 June 2011, 14:58
> >>>  >>>  >Subject: [FFmpeg-devel] {WIP} {HELP} Dvb Subtitles 
> > and Hard Subtitles
> >>>  >>>  >
> >>>  >>>  >Ok needing a bit of help here, ive added my current 
> > diff in the hope of 
> >>>  >> some help from a more knowledgable ffmpeg developer.
> >>>  >>>  >
> >>>  >>>  >My problem is that i need to get the main output loop 
> > to eventually 
> >>>  >> call the do_subtitle_out for every frame of video that is 
> > produced.
> >>>  >>>  >
> >>>  >>>  >I have attempted to change the code where the 
> > subtitle is decoded, only 
> >>>  >> once in the case of dvbsubs, and to output it multiple times, 
> > but the output bit 
> >>>  >> is still only called once.
> >>>  >>>  >
> >>>  >>>  >Can anybody help me in getting the loop to make the 
> > multiple calls to 
> >>>  >> output the subtitles, im trying not to have to write this as a 
> > filter, but to 
> >>>  >> have the subs placed on the output video plane BEFORE resizing 
> > and ENCODING?
> >>>  >>>  >
> >>>  >>>  >If you think im going about it the wrong way then let 
> > me know, and if 
> >>>  >> the only way is to produce a filter i will spend my time on 
> > that instead.
> >>>  >>>  >
> >>>  >>>  >So just for clarity i need to get the subs to be 
> > copied to the video 
> >>>  >> before any resize or encoding is performed, if this works it 
> > should be possible 
> >>>  >> to take any subs and have them placed on the video.
> >>>  >>>  >
> >>>  >>>  >also one more problem is that the TS si still has the 
> > entry for 
> >>>  >> "dvb subs" in its pmt, this will need removing, as i 
> > cant see the 
> >>>  >> point of having hard subs and soft subs whch are the same.
> >>>  >>>  >
> >>>  >>>  >joolz
> >>>  >>>  >
> >>>  >>>  >_______________________________________________
> >>>  >>>  >ffmpeg-devel mailing list
> >>>  >>>  >ffmpeg-devel at ffmpeg.org
> >>>  >>>  >http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >>>  >>>  >
> >>>  >>>  >
> >>>  >>>  >
> >>>  >>> 
> >>>  >>>  Ok boys i have the "hards subs" kind of 
> > working, but i need some 
> >>>  >> help in dumping the subtitles onto the screen in the correct 
> > format.
> >>>  >>> 
> >>>  >>>  I have modified ffmpeg.c and in the routine 
> >>>  >> "pre_process_video_frame" i aim to do the dump of 
> > the subs, im just 
> >>>  >> testing but if i do a memset on the memory pointed at by 
> >>>  >> picture->data[0]+x+y*picture->linesize[0] i get my boxes 
> > in the correct 
> >>>  >> place.
> >>>  >>> 
> >>>  >>>  What i need to do now is translate the subtitles pixel 
> > and clut map into 
> >>>  >> the correct format and add this to the plane, now the good 
> > point of this is that 
> >>>  >> scaling the video works after this.
> >>>  >>> 
> >>>  >>>  Any help please.
> >>>  >> 
> >>>  >> for format convert see swscale (maybe libavfilter/vf_scale.c 
> > is a
> >>>  >> useable example on its useage)
> >>>  >> 
> >>>  >> for blend/overlay of stuff see vf_overlay.c
> >>>  >>     
> >>>  >>     
> >>>  >> [...]
> >>>  >> 
> >>>  >> -- 
> >>>  >> Michael     GnuPG fingerprint: 
> > 9FF2128B147EF6730BADF133611EC787040B0FAB
> >>>  >> 
> >>>  >> The real ebay dictionary, page 2
> >>>  >> "100% positive feedback" - "All either got 
> > their money back or 
> >>>  >> didnt complain"
> >>>  >> "Best seller ever, very honest" - "Seller 
> > refunded buyer after 
> >>>  >> failed scam"
> >>>  >> 
> >>>  >> _______________________________________________
> >>>  >> ffmpeg-devel mailing list
> >>>  >> ffmpeg-devel at ffmpeg.org
> >>>  >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >>>  >>
> >>>  >
> >>>  >OK "Hard Subtitles" working now, test phase to continue 
> > but i have a few queries regarding what should be done with certain cases
> >>>  >
> >>>  >1. dvd-subtitle-problem.vob
> >>>  >  This file has a video size of 352x288 but the dvbsubs are being 
> > displayed out of this range so my options are
> >>>  >    a) Dont render out of visible screen area (current system)
> >>>  >    b) Swscale the video to fix the subtitle expected screen size, 
> > draw subs, recscale back to original size (lots of cpu)
> >>>  >    c) Rescale the subtitles themselves and also the position and 
> > then draw on screen (need a new rescaler)
> >>>  >
> >>>  >2. As i see it .SRT and .SUB decode the subs but dont render them, 
> > what would be good would be for all the subtitle engines to render to a bitmap 
> > buffer, with clut and regions. If this is the case then we could do things like 
> > Hard Subs, Ass->Dvb, Srt-Dvb etc Is this a feasable way forward?
> >>>  >
> >>>  >3. Xsub seems to work now except for the demo i have being a 
> > 720x408 screen and the subtitles are positioned at 174,464, so back to 1
> >>>  >
> >>>  >I need to do more testing but the problem streams i started with 
> > all work well and the subtitles appear where and in the correct colours as they 
> > should.
> >>>  >
> >>>  >I have some encoded files i will put up on my ftp if anyone want to 
> > see some examples or the hard subs
> >>>  >
> >>>  >
> >>>  >joolz
> >>>  >_______________________________________________
> >>>  >ffmpeg-devel mailing list
> >>>  >ffmpeg-devel at ffmpeg.org
> >>>  >http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >>> 
> >>> 
> >>>  OK boys i have another small problem, which im having trouble finding 
> > the cause of?
> >>> 
> >>> 
> >> 
> >>>  When i put "hard subtitles" on the screen i get nice 
> > subtitles, but i also get atrifacts around the subtitles which move around the 
> > subtitle.
> >> 
> >> sounds like you write into the reference frames.
> >> theres no alternative than making a copy
> >> 
> >> [...]
> >> -- 
> >> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> >> 
> >> While the State exists there can be no freedom; when there is freedom there
> >> will be no State. -- Vladimir Lenin
> >> 
> >> _______________________________________________
> >> ffmpeg-devel mailing list
> >> ffmpeg-devel at ffmpeg.org
> >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> > 
> > 
> > Thanks for that, will modify the code and test again.
> > 
> > Now another question. This test is being done on LIVE streams.
> > 
> > Iissue the ffmpeg line without the "-scodec" line everything works as 
> > it should.
> > 
> > Issue with the "-scodec dvbsub" AND THERE ARE dvbsubs in the stream 
> > again we work, not perfectly.
> > 
> > Issue with the "-scodec dvbsub" AND THERE ARE NO SUBS BEING 
> > TRANSMITTED, but the si contains the correct si saying they are there we get a 
> > problem.
> > 
> > What seems to be happening is that the new encoded data is being buffered and is 
> > waiting for the dvbsub title stream to pass data into the stream, what i see is 
> > the status line does not change so we get "time=00:00:00.00 
> > bitrate=0.0kbits/s" and after a while ffmpeg just drops out without an 
> > error
> > 
> > joolz
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> Anybody out there able to help, i have 7 patches which fix most of the DVB Subtitles problems but i can finish my test as i need to be able to get the problem with the bitrate/time not moving when we have dvbsubs marked as being in the stream but there is no data.
> 
> biggest problem happens on live tv when they goto a program without subtitles, ffmpeg just drops back to cli

I am a bit busy but if you have a reproduceable testcase i could try
to take a look

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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