On Mon, Jul 11, 2016 at 05:33:03PM -0500, Burt P. wrote: > Only call hdcd_update_info() when the control code changes > instead of every frame, so the counters are more meaningful. >
> Also, adds some basic error detection. After scanning through > about 30 HDCD-encoded CD's I've found errors where a code > is signaled, but then fails to match one of the patterns, so > it is ignored. Often, it is very close to a code, differing > by only one bit. I don't know enough to say whether it is > using some unknown feature of HDCD that this filter doesn't > know about, or if there was just an error in the encoding. > I've added some comments so that it should be easier for > others to examine. are these 2 seperate changes ? if so they should be in seperate patches/commits > > An example with many errors is Līve - Secret Samadhi, if > anyone wants to look into it. > > Patch is attached. > Any comments would be appreciated. > af_hdcd.c | 122 > ++++++++++++++++++++++++++++++++++++++++---------------------- > 1 file changed, 79 insertions(+), 43 deletions(-) > e787817ad5f053390d648e6bba66f9a2fd5d0e95 > 0001-af_hdcd.c-only-hdcd_update_info-when-something-chang.patch > From 63a2736dd8444fe64d8c5bc885d61979bfe93f6b Mon Sep 17 00:00:00 2001 > From: Burt P <pbu...@gmail.com> > Date: Mon, 11 Jul 2016 17:08:20 -0500 > Subject: [PATCH] af_hdcd.c: only hdcd_update_info() when something changes, > add error detection > MIME-Version: 1.0 > Content-Type: text/plain; charset=UTF-8 > Content-Transfer-Encoding: 8bit > > * hdcd_update_info() when control code changes; counts are more meaningful > * some encoding errors can be detected > * fewer false positives by ignoring code_counterC in HDCD detection > * integrate() renamed hdcd_integrate() to be consistent with the other > function names > * some code comments > > Try Līve - Secret Samadhi or John Mellencamp - Mr. Happy Go Lucky for error > detection. [...] > + av_log(0, AV_LOG_VERBOSE, > + "hdcd error: Control A almost: 0x%08x\n", bits); [...] > + av_log(0, AV_LOG_VERBOSE, > + "hdcd error: Unmatched code: 0x%08x\n", bits); av_log() should have a non null context so that the messages can more easily be associated with their source [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB I do not agree with what you have to say, but I'll defend to the death your right to say it. -- Voltaire
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