lavc: Add mpeg2_metadata bitstream filter

(cherry picked from commit b78c30d7)

configure

@@ -2917,6 +2917,7 @@ h264_metadata_bsf_select="cbs_h264"
 h264_redundant_pps_bsf_select="cbs_h264"
 hevc_metadata_bsf_select="cbs_h265"
 mjpeg2jpeg_bsf_select="jpegtables"
+mpeg2_metadata_bsf_select="cbs_mpeg2"
 trace_headers_bsf_select="cbs_h264 cbs_h265 cbs_mpeg2"
 
 # external libraries

doc/bitstream_filters.texi

@@ -324,6 +324,42 @@ See also the @ref{text2movsub} filter.
 
 Decompress non-standard compressed MP3 audio headers.
 
+@section mpeg2_metadata
+
+Modify metadata embedded in an MPEG-2 stream.
+
+@table @option
+@item display_aspect_ratio
+Set the display aspect ratio in the stream.
+
+The following fixed values are supported:
+@table @option
+@item 4/3
+@item 16/9
+@item 221/100
+@end table
+Any other value will result in square pixels being signalled instead
+(see H.262 section 6.3.3 and table 6-3).
+
+@item frame_rate
+Set the frame rate in the stream.  This is constructed from a table
+of known values combined with a small multiplier and divisor - if
+the supplied value is not exactly representable, the nearest
+representable value will be used instead (see H.262 section 6.3.3
+and table 6-4).
+
+@item video_format
+Set the video format in the stream (see H.262 section 6.3.6 and
+table 6-6).
+
+@item colour_primaries
+@item transfer_characteristics
+@item matrix_coefficients
+Set the colour description in the stream (see H.262 section 6.3.6
+and tables 6-7, 6-8 and 6-9).
+
+@end table
+
 @section mpeg4_unpack_bframes
 
 Unpack DivX-style packed B-frames.

libavcodec/Makefile

@@ -1027,6 +1027,7 @@ OBJS-$(CONFIG_MPEG4_UNPACK_BFRAMES_BSF)   += mpeg4_unpack_bframes_bsf.o
 OBJS-$(CONFIG_MOV2TEXTSUB_BSF)            += movsub_bsf.o
 OBJS-$(CONFIG_MP3_HEADER_DECOMPRESS_BSF)  += mp3_header_decompress_bsf.o \
                                              mpegaudiodata.o
+OBJS-$(CONFIG_MPEG2_METADATA_BSF)         += mpeg2_metadata_bsf.o
 OBJS-$(CONFIG_NOISE_BSF)                  += noise_bsf.o
 OBJS-$(CONFIG_NULL_BSF)                   += null_bsf.o
 OBJS-$(CONFIG_REMOVE_EXTRADATA_BSF)       += remove_extradata_bsf.o

libavcodec/bitstream_filters.c

@@ -38,6 +38,7 @@ extern const AVBitStreamFilter ff_imx_dump_header_bsf;
 extern const AVBitStreamFilter ff_mjpeg2jpeg_bsf;
 extern const AVBitStreamFilter ff_mjpega_dump_header_bsf;
 extern const AVBitStreamFilter ff_mp3_header_decompress_bsf;
+extern const AVBitStreamFilter ff_mpeg2_metadata_bsf;
 extern const AVBitStreamFilter ff_mpeg4_unpack_bframes_bsf;
 extern const AVBitStreamFilter ff_mov2textsub_bsf;
 extern const AVBitStreamFilter ff_noise_bsf;