[FFmpeg-devel] [PATCH] Allow DTS audio copy to TS streams

Michael Niedermayer michaelni at gmx.at
Sun Apr 27 14:23:58 CEST 2014


On Sun, Apr 27, 2014 at 04:23:25AM +0000, goodthanks wrote:
> Timothy Gu <timothygu99 <at> gmail.com> writes:
> > 
> > On Apr 26, 2014 11:01 AM, "Tamlyn Ellis" <tamlyn <at> internode.on.net> wrote:
> > > Also I was supposed to put "fixes ticket 1398" on the description but
> > > I'm a bit of a noob at this stuff. More details here
> > > http://trac.ffmpeg.org/ticket/1398
> > 
> > I added a comment on Git usage on the ticket. You might want to check it
> > out. Also, please don't top post here:
> > 
> > https://en.wikipedia.org/wiki/Posting_style#Top-posting
> > 
> > [...]
> > 
> > Timothy
> > 
> Sorry I just replied on my email client and it has caused a top post here. I
> just found this site on google.
> Not overly impressed about my full name and email address placed on a public
> site that doesn't require a login to see. Guess that is my own fault for not
> understanding the process...
> Too late to do anything about it now I suppose?

yes, there are many public mirrors of the mailing list which are not
under our control, also each subscriber has a copy of the mail

> So do I need to run the patch again with the changes you suggested or just
> leave it now?

ive just made the change and applied it

> Probably a couple of things that should be noted.
> This doesn't allow encoding of DTS or TrueHD. It just sets the correct
> stream ID in the TS output file when a DTS or TrueHD audio stream is copied.
> Also there are actually 3 different DTS types that matroska gives the
> codec_ID of A_DTS to
> DTS 0x82
> DTS-HR (High Resolution)0x85
> DTS-MA (Master Audio)0x86
> Because matroska lists all of these as A_DTS this patch will mean ffmpeg
> sets 0x82 as the stream ID for all 3 DTS types above in TS output files.
> Personally it works for me as my hardware plays the DTS-HR stream correctly
> with either the correct stream ID of 0x85 or the technically incorrect 0x82.
> I have not been able to confirm the DTS-MA stream yet. I cant find a sample
> that will actually display on my DLNA client.
> I would think it will cause issues on hardware/software with stricter
> compliance to the stream ID's.

> The only way to get it completely accurate for matroska input files would be
> check the stream for number of channels, bitrate and sampling frequency.

yes, the muxer would have to check the data or call some other code
like the dts parser (libavcodec/dca_parser.c) (see av_parser_init and
related code)

also theres another dts stream type define in libavformat/mpeg.h
should that be changed too ?
if so please send a patch for that too, as well as the parser
stuff to get the exact dts type if you want



Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Good people do not need laws to tell them to act responsibly, while bad
people will find a way around the laws. -- Plato
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