[vlc-devel] Uploaded sample transport stream with failing CC's

Paul Fernquist fernqui at hotmail.com
Thu Jul 9 20:14:44 CEST 2009

I ftp'ed to streams.videolan.org/incoming CC_TNT_Comcast_Sample.[txt,ts]
files to start a discussion of a weird case of CC's that actually use field
3 for CC data.

I recorded the stream using an HD Homerun capture card of a Comcast cable
show on TNT.

The problem with CC's is there are so many orgs specing CCs in mpeg user
data, it is impossible to find documentation sometimes. My clear QAM TV
displays the CC's fine so there has to be a spec somewhere. I proposed a fix
that looks at the mpeg top_field_first bit to determine the field numbers.
The fix seems to work for my case. See
http://neuron2.net/library/mpeg2/iso13818-2.pdf section 6.3.10 for the
top_field_first description.

Also, the wikipedia suggests looking at bit 11 of the d1d2 command pair to
determine the channel. Two fields for each channel gives CC1, CC2, CC3 and
CC4. http://en.wikipedia.org/wiki/EIA-608

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