lavc, doc, configure: add avs2 video decoder wrapper

Tested-by: Steven Liu <lq@chinaffmpeg.org>
Signed-off-by: hwren <hwrenx@126.com>
Signed-off-by: Steven Liu <lq@chinaffmpeg.org>

Changelog

@@ -16,6 +16,7 @@ version <next>:
 - ATRAC9 decoder
 - lensfun wrapper filter
 - colorconstancy filter
+- AVS2 video decoder via libdavs2
 
 
 version 4.0:

configure

@@ -226,6 +226,7 @@ External library support:
   --enable-libcelt         enable CELT decoding via libcelt [no]
   --enable-libcdio         enable audio CD grabbing with libcdio [no]
   --enable-libcodec2       enable codec2 en/decoding using libcodec2 [no]
+  --enable-libdavs2        enable AVS2 decoding via libdavs2 [no]
   --enable-libdc1394       enable IIDC-1394 grabbing using libdc1394
                            and libraw1394 [no]
   --enable-libfdk-aac      enable AAC de/encoding via libfdk-aac [no]
@@ -1639,6 +1640,7 @@ EXTERNAL_LIBRARY_GPL_LIST="
     avisynth
     frei0r
     libcdio
+    libdavs2
     librubberband
     libvidstab
     libx264
@@ -3052,6 +3054,7 @@ libaom_av1_encoder_select="extract_extradata_bsf"
 libcelt_decoder_deps="libcelt"
 libcodec2_decoder_deps="libcodec2"
 libcodec2_encoder_deps="libcodec2"
+libdavs2_decoder_deps="libdavs2"
 libfdk_aac_decoder_deps="libfdk_aac"
 libfdk_aac_encoder_deps="libfdk_aac"
 libfdk_aac_encoder_select="audio_frame_queue"
@@ -6011,6 +6014,7 @@ enabled libcelt           && require libcelt celt/celt.h celt_decode -lcelt0 &&
                                die "ERROR: libcelt must be installed and version must be >= 0.11.0."; }
 enabled libcaca           && require_pkg_config libcaca caca caca.h caca_create_canvas
 enabled libcodec2         && require libcodec2 codec2/codec2.h codec2_create -lcodec2
+enabled libdavs2          && require_pkg_config libdavs2 "davs2 >= 1.5.115" davs2.h davs2_decoder_open
 enabled libdc1394         && require_pkg_config libdc1394 libdc1394-2 dc1394/dc1394.h dc1394_new
 enabled libdrm            && require_pkg_config libdrm libdrm xf86drm.h drmGetVersion
 enabled libfdk_aac        && { check_pkg_config libfdk_aac fdk-aac "fdk-aac/aacenc_lib.h" aacEncOpen ||

doc/decoders.texi

@@ -47,6 +47,12 @@ top-field-first is assumed
 
 @end table
 
+@section libdavs2
+
+AVS2/IEEE 1857.4 video decoder wrapper.
+
+This decoder allows libavcodec to decode AVS2 streams with davs2 library.
+
 @c man end VIDEO DECODERS
 
 @chapter Audio Decoders

doc/general.texi

@@ -17,6 +17,20 @@ for more formats. None of them are used by default, their use has to be
 explicitly requested by passing the appropriate flags to
 @command{./configure}.
 
+@section libdavs2
+
+FFmpeg can make use of the davs2 library for AVS2/IEEE 1857.4 video decoding.
+
+Go to @url{https://github.com/pkuvcl/davs2} and follow the instructions for
+installing the library. Then pass @code{--enable-libdavs2} to configure to
+enable it.
+
+@float NOTE
+libdavs2 is under the GNU Public License Version 2 or later
+(see @url{http://www.gnu.org/licenses/old-licenses/gpl-2.0.html} for
+details), you must upgrade FFmpeg's license to GPL in order to use it.
+@end float
+
 @section Alliance for Open Media libaom
 
 FFmpeg can make use of the libaom library for AV1 decoding.

libavcodec/Makefile

@@ -946,6 +946,7 @@ OBJS-$(CONFIG_LIBAOM_AV1_ENCODER)         += libaomenc.o
 OBJS-$(CONFIG_LIBCELT_DECODER)            += libcelt_dec.o
 OBJS-$(CONFIG_LIBCODEC2_DECODER)          += libcodec2.o codec2utils.o
 OBJS-$(CONFIG_LIBCODEC2_ENCODER)          += libcodec2.o codec2utils.o
+OBJS-$(CONFIG_LIBDAVS2_DECODER)           += libdavs2.o
 OBJS-$(CONFIG_LIBFDK_AAC_DECODER)         += libfdk-aacdec.o
 OBJS-$(CONFIG_LIBFDK_AAC_ENCODER)         += libfdk-aacenc.o
 OBJS-$(CONFIG_LIBGSM_DECODER)             += libgsmdec.o

libavcodec/allcodecs.c

@@ -668,6 +668,7 @@ extern AVCodec ff_libaom_av1_encoder;
 extern AVCodec ff_libcelt_decoder;
 extern AVCodec ff_libcodec2_encoder;
 extern AVCodec ff_libcodec2_decoder;
+extern AVCodec ff_libdavs2_decoder;
 extern AVCodec ff_libfdk_aac_encoder;
 extern AVCodec ff_libfdk_aac_decoder;
 extern AVCodec ff_libgsm_encoder;