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New webpsave option smart_subsample 

This enables a high quality RGB to YUV converter in libwebp which
greatly improves the quality of fine details by reducing color bleeding
caused by the 4:2:0 chroma subsampling. This is slower and causes
slightly larger files. See WebPPictureSmartARGBToYUVA in libwebp.
This commit is contained in:
Felix Bünemann 2016-04-23 01:20:41 +02:00
parent f834ea39f6
commit 58a2616f77
4 changed files with 37 additions and 11 deletions
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2
libvips/foreign/foreign.c
View File

@ -2460,6 +2460,7 @@ vips_webpload_buffer( void *buf, size_t len, VipsImage **out, ... )
* @Q: quality factor
* @lossless: enables lossless compression
* @preset: #VipsForeignWebpPreset choose lossy compression preset
* @smart_subsample: enables high quality chroma subsampling
*
* See also: vips_webpload(), vips_image_write_to_file().
*
@ -2490,6 +2491,7 @@ vips_webpsave( VipsImage *in, const char *filename, ... )
* @Q: JPEG quality factor
* @lossless: enables lossless compression
* @preset: #VipsForeignWebpPreset choose lossy compression preset
* @smart_subsample: enables high quality chroma subsampling
*
* See also: vips_webpsave().
*

20
libvips/foreign/vips2webp.c
View File

@ -84,7 +84,8 @@ get_preset( VipsForeignWebpPreset preset )
static int
write_webp( WebPPicture *pic, VipsImage *in,
int Q, gboolean lossless, VipsForeignWebpPreset preset )
int Q, gboolean lossless, VipsForeignWebpPreset preset,
gboolean smart_subsample )
{
VipsImage *memory;
WebPConfig config;
@ -97,6 +98,8 @@ write_webp( WebPPicture *pic, VipsImage *in,
}
config.lossless = lossless;
if( smart_subsample )
config.preprocessing |= 4;
if( !WebPValidateConfig(&config) ) {
vips_error( "vips2webp",
@ -107,7 +110,10 @@ write_webp( WebPPicture *pic, VipsImage *in,
if( !(memory = vips_image_copy_memory( in )) )
return( -1 );
pic->use_argb = lossless;
/* Smart subsampling requires use_argb because
* it is applied during RGB to YUV conversion.
*/
pic->use_argb = lossless || smart_subsample;
pic->width = memory->Xsize;
pic->height = memory->Ysize;
@ -138,7 +144,8 @@ write_webp( WebPPicture *pic, VipsImage *in,
int
vips__webp_write_file( VipsImage *in, const char *filename,
int Q, gboolean lossless, VipsForeignWebpPreset preset )
int Q, gboolean lossless, VipsForeignWebpPreset preset,
gboolean smart_subsample )
{
WebPPicture pic;
WebPMemoryWriter writer;
@ -154,7 +161,7 @@ vips__webp_write_file( VipsImage *in, const char *filename,
pic.writer = WebPMemoryWrite;
pic.custom_ptr = &writer;
if( write_webp( &pic, in, Q, lossless, preset ) ) {
if( write_webp( &pic, in, Q, lossless, preset, smart_subsample ) ) {
WebPPictureFree( &pic );
WebPMemoryWriterClear( &writer );
return -1;
@ -181,7 +188,8 @@ vips__webp_write_file( VipsImage *in, const char *filename,
int
vips__webp_write_buffer( VipsImage *in, void **obuf, size_t *olen,
int Q, gboolean lossless, VipsForeignWebpPreset preset )
int Q, gboolean lossless, VipsForeignWebpPreset preset,
gboolean smart_subsample )
{
WebPPicture pic;
WebPMemoryWriter writer;
@ -197,7 +205,7 @@ vips__webp_write_buffer( VipsImage *in, void **obuf, size_t *olen,
pic.writer = WebPMemoryWrite;
pic.custom_ptr = &writer;
if( write_webp( &pic, in, Q, lossless, preset ) ) {
if( write_webp( &pic, in, Q, lossless, preset, smart_subsample ) ) {
WebPPictureFree( &pic );
WebPMemoryWriterClear( &writer );
return -1;

6
libvips/foreign/webp.h
View File

@ -49,9 +49,11 @@ int vips__webp_read_buffer( const void *buf, size_t len,
VipsImage *out, int shrink );
int vips__webp_write_file( VipsImage *out, const char *filename,
int Q, gboolean lossless, VipsForeignWebpPreset preset );
int Q, gboolean lossless, VipsForeignWebpPreset preset,
gboolean smart_subsample );
int vips__webp_write_buffer( VipsImage *out, void **buf, size_t *len,
int Q, gboolean lossless, VipsForeignWebpPreset preset );
int Q, gboolean lossless, VipsForeignWebpPreset preset,
gboolean smart_subsample );
#ifdef __cplusplus
}

20
libvips/foreign/webpsave.c
View File

@ -64,6 +64,10 @@ typedef struct _VipsForeignSaveWebp {
*/
VipsForeignWebpPreset preset;
/* Enable smart chroma subsampling.
*/
gboolean smart_subsample;
} VipsForeignSaveWebp;
typedef VipsForeignSaveClass VipsForeignSaveWebpClass;
@ -121,6 +125,13 @@ vips_foreign_save_webp_class_init( VipsForeignSaveWebpClass *class )
VIPS_TYPE_FOREIGN_WEBP_PRESET,
VIPS_FOREIGN_WEBP_PRESET_DEFAULT );
VIPS_ARG_BOOL( class, "smart_subsample", 13,
_( "Smart subsampling" ),
_( "Enable high quality chroma subsampling" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsForeignSaveWebp, smart_subsample ),
FALSE );
}
static void
@ -155,7 +166,8 @@ vips_foreign_save_webp_file_build( VipsObject *object )
return( -1 );
if( vips__webp_write_file( save->ready, file->filename,
webp->Q, webp->lossless, webp->preset ) )
webp->Q, webp->lossless, webp->preset,
webp->smart_subsample ) )
return( -1 );
return( 0 );
@ -217,7 +229,8 @@ vips_foreign_save_webp_buffer_build( VipsObject *object )
return( -1 );
if( vips__webp_write_buffer( save->ready, &obuf, &olen,
webp->Q, webp->lossless, webp->preset ) )
webp->Q, webp->lossless, webp->preset,
webp->smart_subsample ) )
return( -1 );
blob = vips_blob_new( (VipsCallbackFn) vips_free, obuf, olen );
@ -278,7 +291,8 @@ vips_foreign_save_webp_mime_build( VipsObject *object )
return( -1 );
if( vips__webp_write_buffer( save->ready, &obuf, &olen,
webp->Q, webp->lossless, webp->preset ) )
webp->Q, webp->lossless, webp->preset,
webp->smart_subsample ) )
return( -1 );
printf( "Content-length: %zu\r\n", olen );