GST_VIDEO_BUFFER_FLAG_INTERLACED and GST_VIDEO_BUFFER_FLAG_TFF
flags are needed when processing SCTE 20 closed captions for an interlaced
stream, when we need to convert back to analog, in which case we need to match
the caption to the top or bottom field
Fixes the following error.
gstccconverter.c:677:7: error: variable 'len' is used uninitialized whenever 'if' condition is false
[-Werror,-Wsometimes-uninitialized]
if (flags & 0x40) {
^~~~~~~~~~~~
gstccconverter.c:698:10: note: uninitialized use occurs here
return len;
^~~
gstccconverter.c:677:3: note: remove the 'if' if its condition is always true
if (flags & 0x40) {
^~~~~~~~~~~~~~~~~~
gstccconverter.c:572:12: note: initialize the variable 'len' to silence this warning
guint len;
^
= 0
Prior to this, cccombiner stopped consuming video buffers when
data wasn't arriving on its caption pad. In a live situation,
when aggregator is timing out we should still output whatever
video buffers are present, even if no caption buffers can be
aggregated with them.
It is necessary to implement this vmethod, as when the src pad
is marked as reconfigure, the base class will reset to src caps,
and the default update_src_caps simply queries the caps allowed
downstream without taking into account the caps set by
gst_aggregator_set_src_caps.
As a side-effect we can now actually store the line offset in the
line21dec element, and have to perform fewer transformations in the
decklink elements (which were also buggy as they assumed a single byte
triplet per meta).
It depends on the framerate how many cc_data byte pairs are allowed per
frame, and the framerate is also needed for converting into the CDP or
MCC format as the framerate is part of the header metadata.
When compiling with clang-6 this error raises:
raw_decoder.c:411:1: error: unused function 'cpr1204_crc'
[-Werror,-Wunused-function]
This patch only comments it out.
https://bugzilla.gnome.org/show_bug.cgi?id=796957
When compiling with clang-6 this error pops out:
raw_decoder.c:1011:62: error: implicit conversion from enumeration
type 'const vbi_modulation' to different enumeration type
'vbi3_modulation' [-Werror,-Wenum-conversion]
This is because function vbi3_bit_slicer_set_params() sets
vbi3_modulation as enum type parameter, nonetheless vbi_modulation
enum is passed. Both enums looks semantically equal, thus the fix is a
simple cast.
https://bugzilla.gnome.org/show_bug.cgi?id=796957
This new element allows decoding and overlaying CEA-708 Closed Caption
streams over video.
* Supports CDP and cc_data closedcaption/x-cea-708 streams
* Uses pango to render CC stream
* Support GstVideoOverlayComposition meta if downstream supports is
Tested on various test files.
Remains to be fixed/improved:
* Switch to GstByteReader (for code safety)
* Switch to GString (instead of manual pango string construction)
* Move pango/rendering code outside of main 708 decoder file (so
that actual CC parser/decoder can be (re)used in other scenarios).
Initial patches and improvements by:
* CableLabs RUIH-RI Team <ruihri@cablelabs.com>
* Steve Maynard <steve@secondstryke.com>
* cjun.wang" <cjun.wang@samsung.com>
https://bugzilla.gnome.org/show_bug.cgi?id=704881
zvbi switched to a lot more flexible CC detection in VBI.
The problem is that it returns a *lot* of non-VBI lines as containing
CC which isn't the case.
Current code from zapping/zvbi as of 2018-03-14. Files copied
are all LGPL v2+.
Changes from original zvbi code:
* Switch to gst-debug logging system
* Use glib for endianness detection
* Fix compilation warnings
Allows extracting GstVideoCaptionMeta from a stream and outputs
it to a standalone stream.
Part of a new 'ext' closedcaption plugin, since more features are
going to be added, which will depend on external dependencies such
as pango.
