Add a libwebp encoder

Changelog

@@ -52,6 +52,7 @@ version 10:
 - remove mp3_header_(de)compress bitstream filters
 - stereoscopic 3d metadata handling
 - png standalone parser
+- WebP encoding via libwebp
 
 
 version 9:

configure

@@ -202,6 +202,7 @@ External library support:
   --enable-libvorbis       enable Vorbis encoding via libvorbis [no]
   --enable-libvpx          enable VP8 and VP9 de/encoding via libvpx [no]
   --enable-libwavpack      enable wavpack encoding via libwavpack [no]
+  --enable-libwebp         enable WebP encoding via libwebp [no]
   --enable-libx264         enable H.264 encoding via x264 [no]
   --enable-libxavs         enable AVS encoding via xavs [no]
   --enable-libxvid         enable Xvid encoding via xvidcore,
@@ -1116,6 +1117,7 @@ EXTERNAL_LIBRARY_LIST="
     libvorbis
     libvpx
     libwavpack
+    libwebp
     libx264
     libxavs
     libxvid
@@ -1867,6 +1869,7 @@ libvpx_vp8_encoder_deps="libvpx"
 libvpx_vp9_decoder_deps="libvpx"
 libvpx_vp9_encoder_deps="libvpx"
 libwavpack_encoder_deps="libwavpack"
+libwebp_encoder_deps="libwebp"
 libx264_encoder_deps="libx264"
 libxavs_encoder_deps="libxavs"
 libxvid_encoder_deps="libxvid"
@@ -3926,6 +3929,7 @@ enabled libvpx            && {
     enabled libvpx_vp9_decoder && { check_lib2 "vpx/vpx_decoder.h vpx/vp8dx.h" "vpx_codec_vp9_dx" -lvpx || disable libvpx_vp9_decoder; }
     enabled libvpx_vp9_encoder && { check_lib2 "vpx/vpx_encoder.h vpx/vp8cx.h" "vpx_codec_vp9_cx" -lvpx || disable libvpx_vp9_encoder; } }
 enabled libwavpack        && require libwavpack wavpack/wavpack.h WavpackOpenFileOutput  -lwavpack
+enabled libwebp           && require_pkg_config libwebp webp/encode.h WebPGetEncoderVersion
 enabled libx264           && require libx264 x264.h x264_encoder_encode -lx264 &&
                              { check_cpp_condition x264.h "X264_BUILD >= 118" ||
                                die "ERROR: libx264 version must be >= 0.118."; }

doc/encoders.texi

@@ -446,6 +446,67 @@ Same as 3, but with extra processing enabled - corresponding to the wavpack
 @chapter Video Encoders
 @c man begin VIDEO ENCODERS
 
+@section libwebp
+
+libwebp WebP Image encoder wrapper
+
+libwebp is Google's official encoder for WebP images. It can encode in either
+lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
+frame. Lossless images are a separate codec developed by Google.
+
+@subsection Pixel Format
+
+Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
+to limitations of the format and libwebp. Alpha is supported for either mode.
+Because of API limitations, if RGB is passed in when encoding lossy or YUV is
+passed in for encoding lossless, the pixel format will automatically be
+converted using functions from libwebp. This is not ideal and is done only for
+convenience.
+
+@subsection Options
+
+@table @option
+
+@item -lossless @var{boolean}
+Enables/Disables use of lossless mode. Default is 0.
+
+@item -compression_level @var{integer}
+For lossy, this is a quality/speed tradeoff. Higher values give better quality
+for a given size at the cost of increased encoding time. For lossless, this is
+a size/speed tradeoff. Higher values give smaller size at the cost of increased
+encoding time. More specifically, it controls the number of extra algorithms
+and compression tools used, and varies the combination of these tools. This
+maps to the @var{method} option in libwebp. The valid range is 0 to 6.
+Default is 4.
+
+@item -qscale @var{float}
+For lossy encoding, this controls image quality, 0 to 100. For lossless
+encoding, this controls the effort and time spent at compressing more. The
+default value is 75. Note that for usage via libavcodec, this option is called
+@var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
+
+@item -preset @var{type}
+Configuration preset. This does some automatic settings based on the general
+type of the image.
+@table @option
+@item none
+Do not use a preset.
+@item default
+Use the encoder default.
+@item picture
+Digital picture, like portrait, inner shot
+@item photo
+Outdoor photograph, with natural lighting
+@item drawing
+Hand or line drawing, with high-contrast details
+@item icon
+Small-sized colorful images
+@item text
+Text-like
+@end table
+
+@end table
+
 @section libx264
 
 x264 H.264/MPEG-4 AVC encoder wrapper

doc/general.texi

@@ -415,8 +415,8 @@ following image formats are supported:
     @tab YUV, JPEG and some extension is not supported yet.
 @item Truevision Targa  @tab X @tab X
     @tab Targa (.TGA) image format
-@item WebP         @tab @tab X
-    @tab WebP image format
+@item WebP         @tab E @tab X
+    @tab WebP image format, encoding supported through external library libwebp
 @item XBM  @tab X @tab
     @tab X BitMap image format
 @item XWD  @tab X @tab X

libavcodec/Makefile

@@ -612,6 +612,7 @@ OBJS-$(CONFIG_LIBVPX_VP8_ENCODER)         += libvpxenc.o
 OBJS-$(CONFIG_LIBVPX_VP9_DECODER)         += libvpxdec.o libvpx.o
 OBJS-$(CONFIG_LIBVPX_VP9_ENCODER)         += libvpxenc.o libvpx.o
 OBJS-$(CONFIG_LIBWAVPACK_ENCODER)         += libwavpackenc.o
+OBJS-$(CONFIG_LIBWEBP_ENCODER)            += libwebpenc.o
 OBJS-$(CONFIG_LIBX264_ENCODER)            += libx264.o
 OBJS-$(CONFIG_LIBXAVS_ENCODER)            += libxavs.o
 OBJS-$(CONFIG_LIBXVID_ENCODER)            += libxvid.o

libavcodec/allcodecs.c

@@ -437,6 +437,7 @@ void avcodec_register_all(void)
     REGISTER_ENCDEC (LIBVPX_VP8,        libvpx_vp8);
     REGISTER_ENCDEC (LIBVPX_VP9,        libvpx_vp9);
     REGISTER_ENCODER(LIBWAVPACK,        libwavpack);
+    REGISTER_ENCODER(LIBWEBP,           libwebp);
     REGISTER_ENCODER(LIBX264,           libx264);
     REGISTER_ENCODER(LIBXAVS,           libxavs);
     REGISTER_ENCODER(LIBXVID,           libxvid);