[FFmpeg-devel] [FFmpeg-user] BUG in use of extradata and extradata_size with dvb subtitles and teletext
joolzg at btinternet.com
Thu Dec 19 17:18:29 CET 2013
----- Original Message -----
> From: Clément Bœsch <u at pkh.me>
> To: FFmpeg user questions <ffmpeg-user at ffmpeg.org>
> Sent: Thursday, 19 December 2013, 16:29
> Subject: Re: [FFmpeg-user] BUG in use of extradata and extradata_size with dvb subtitles and teletext
> On Thu, Dec 19, 2013 at 03:26:44PM +0000, JULIAN GARDNER wrote:
>> ----- Original Message -----
>> > From: Clément Bœsch <u at pkh.me>
>> > To: FFmpeg user questions <ffmpeg-user at ffmpeg.org>
>> > Cc:
>> > Sent: Thursday, 19 December 2013, 16:07
>> > Subject: Re: [FFmpeg-user] BUG in use of extradata and extradata_size
> with dvb subtitles and teletext
>> > On Thu, Dec 19, 2013 at 02:01:57PM +0000, JULIAN GARDNER wrote:
>> >> Im trying to work though the problems we have in converting
>> > teletext/dvbsubs to the various systems,
>> > Cool, I'm looking forward this.
>> > [...]
>> >> 2. dvbsubs reencoded FAILS
>> > [...]
>> >> 3. dvbsubs copied FAILS
>> >> Command line
>> >> ffmpeg -i ../testStreams/bbc.ts -c:v libx264 -b:v 1300k -c:s copy
> -y -f
>> > mpegts a_dvb.ts
>> >> This runs though the encode cycle but i have yet to find
>> > vlc/ffplay/etc that will show the subtitles. Get "invalid
> subtitle stream
>> > id" in vlc
>> >> Any ideas on the problem in number 2?
>> >> I get onto number 3 when i have number 2 fixed.
>> > Don't you think you should look at the the remuxing problem (3)
> instead of
>> > the encoding first, since you need a correct demuxing/muxing for
>> > this?
>> Remuxing problems go away as soon as you remove the hack in ffmpeg.c for
> doing the dual packet!
> Isn't the dual packet hack only called with transcoding?
> Also, we should move this discussion to ffmpeg-devel.
OK, ive posted this here as requested,
What is needed to get working in order to fix other things
1. When creating a DVBSUBS encoder stream, need the extradata and extradata_size to have the associated values from the input source copied across if dvbsubs, if not dvbsubs then ths needs creating with the defailt values of 0x0001 0x0001. Pointers please as to where this should be done.
2. The timeout value from the incoming dvbsubs needs to be taken into account in the ffmpeg transcode loop so if this expires a new subtitle packet is created with 0 objects, in essence a clear screen, BUT only when the timer expires
More information about the ffmpeg-devel