[FFmpeg-trac] #4441(avfilter:open): support HDCD
FFmpeg
trac at avcodec.org
Sat Nov 28 03:24:01 CET 2015
#4441: support HDCD
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Reporter: calestyo | Owner:
Type: enhancement | Status: open
Priority: wish | Component: avfilter
Version: git-master | Resolution:
Keywords: hdcd | Blocked By:
Blocking: | Reproduced by developer: 1
Analyzed by developer: 0 |
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Comment (by cyclonus):
Jim Lesurf has written some information about HDCP on his homepage:
http://www.audiomisc.co.uk/HFN/HDCD/Enigma.html
He has also written misc. audio software:
http://www.audiomisc.co.uk/software/index.html
Here he provides the source code for a HDCP decoder:
http://www.audiomisc.co.uk/software/WAV_HDCDexpander.tgz
I've successfully compiled PlainVersion.c after some minor 64-bit fixes
i.e. I had to replace "long" with "uint32_t" in the three structs
(wav_header, wav_format, wav_data) for obvious reasons.
I compiled it as follows:
cc -W -Wall -Wformat=2 -O2 -lm -o hdcd PlainVersion.c
The resulting executable takes the input file as first and output file as
second argument.
Next, I've ripped the only HDCD I own with cdparanoia and converted all
WAV files with
the hdcd tool. Apparently it recognized HDCP information in all tracks.
It seems because the output is a "legacy WAVE" file, mplayer didn't want
to play them as 24-bit files. After converting them to FLAC "ignoring
WARNING: legacy WAVE file has format type 1 but bits-per-sample=24", they
are played as 24-bit files without downsampling to 16-bit.
The HDCD-decoded files sound different but, of course, I have no way to
tell whether that's what they're supposed to sound like.
Further, I tried the same with a normal audio CD. No HDCP information was
detected.
Last, I've also downloaded the sample files HDCD32.flac and HDCD16.flac
and converted them both to WAV. The tool correctly detects HDCD
information in HDCD16.wav. The output is identical to HDCD32.wav - except
for header.cksize (3 bytes in the header).
--
Ticket URL: <https://trac.ffmpeg.org/ticket/4441#comment:13>
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