heifsave: make it possible to use a specific encoder (#3198)

* heifsave: make it possible to use a specific encoder

* argument label: switch to leading capital letter

Co-authored-by: Kleis Auke Wolthuizen <github@kleisauke.nl>

* add VipsForeignHeifEncoder enum

* correct type

* implement reviewer feedback

Co-authored-by: Kleis Auke Wolthuizen <github@kleisauke.nl>

ChangeLog

@@ -26,6 +26,7 @@ master
 - GIF load supports truncated frames [tlsa]
 - EXIF support for PNG load and save
 - deprecate gifsave reoptimise, add reuse
+- add "encoder" to heifsave [dloebl]
 
 9/11/22 started 8.13.4
 - missing include in mosaic_fuzzer [ServOKio]

libvips/foreign/foreign.c

@@ -2250,6 +2250,7 @@ vips_heifload_source( VipsSource *source, VipsImage **out, ... )
  * * @compression: #VipsForeignHeifCompression, write with this compression
  * * @effort: %gint, encoding effort
  * * @subsample_mode: #VipsForeignSubsample, chroma subsampling mode
+ * * @encoder: #VipsForeignHeifEncoder, select encoder to use
  *
  * Write a VIPS image to a file in HEIF format. 
  *
@@ -2258,7 +2259,7 @@ vips_heifload_source( VipsSource *source, VipsImage **out, ... )
  *
  * Set @lossless %TRUE to switch to lossless compression.
  *
- * Use @compression to set the encoder e.g. HEVC, AVC, AV1. It defaults to AV1
+ * Use @compression to set the compression format e.g. HEVC, AVC, AV1 to use. It defaults to AV1
  * if the target filename ends with ".avif", otherwise HEVC.
  *
  * Use @effort to control the CPU effort spent improving compression.
@@ -2271,6 +2272,8 @@ vips_heifload_source( VipsSource *source, VipsImage **out, ... )
  * Use @bitdepth to set the bitdepth of the output file. HEIC supports at
  * least 8, 10 and 12 bits; other codecs may support more or fewer options.
  *
+ * Use @encoder to set the encode library to use, e.g. aom, SVT-AV1, rav1e etc.
+ *
  * See also: vips_image_write_to_file(), vips_heifload().
  *
  * Returns: 0 on success, -1 on error.
@@ -2303,6 +2306,7 @@ vips_heifsave( VipsImage *in, const char *filename, ... )
  * * @compression: #VipsForeignHeifCompression, write with this compression
  * * @effort: %gint, encoding effort
  * * @subsample_mode: #VipsForeignSubsample, chroma subsampling mode
+ * * @encoder: #VipsForeignHeifEncoder, select encoder to use
  *
  * As vips_heifsave(), but save to a memory buffer. 
  *
@@ -2356,6 +2360,7 @@ vips_heifsave_buffer( VipsImage *in, void **buf, size_t *len, ... )
  * * @compression: #VipsForeignHeifCompression, write with this compression
  * * @effort: %gint, encoding effort
  * * @subsample_mode: #VipsForeignSubsample, chroma subsampling mode
+ * * @encoder: #VipsForeignHeifEncoder, select encoder to use
  *
  * As vips_heifsave(), but save to a target.
  *

libvips/foreign/heifsave.c

@@ -99,6 +99,10 @@ typedef struct _VipsForeignSaveHeif {
 	 */
 	VipsForeignSubsample subsample_mode;
 
+	/* Encoder to use. For instance: aom, svt etc.
+	 */
+	VipsForeignHeifEncoder selected_encoder;
+
 	/* The image we save. This is a copy of save->ready since we need to
 	 * be able to update the metadata.
 	 */
@@ -438,6 +442,7 @@ vips_foreign_save_heif_build( VipsObject *object )
 	struct heif_error error;
 	struct heif_writer writer;
 	char *chroma;
+	const struct heif_encoder_descriptor* out_encoder;
 
 	if( VIPS_OBJECT_CLASS( vips_foreign_save_heif_parent_class )->
 		build( object ) )
@@ -465,9 +470,36 @@ vips_foreign_save_heif_build( VipsObject *object )
                         heif->image->Type == VIPS_INTERPRETATION_GREY16 ? 
                                 12 : 8;
 
-	error = heif_context_get_encoder_for_format( heif->ctx, 
-		(enum heif_compression_format) heif->compression, 
-		&heif->encoder );
+	/* Try to find the selected encoder.
+	 */
+	if( heif->selected_encoder != VIPS_FOREIGN_HEIF_ENCODER_AUTO ) {
+		const int count = heif_context_get_encoder_descriptors(
+			heif->ctx,
+			(enum heif_compression_format) heif->compression,
+			vips_enum_nick( VIPS_TYPE_FOREIGN_HEIF_ENCODER,
+				heif->selected_encoder ),
+			&out_encoder, 1 );
+
+		if( count > 0 ) {
+			error = heif_context_get_encoder( heif->ctx,
+				out_encoder, &heif->encoder );
+		}
+		else {
+			g_warning(
+			"heifsave: could not find selected encoder %s",
+			vips_enum_nick( VIPS_TYPE_FOREIGN_HEIF_ENCODER,
+				heif->selected_encoder ) );
+		}
+	}
+
+	/* Fallback to default encoder.
+	 */
+	if( !heif->encoder ) {
+		error = heif_context_get_encoder_for_format( heif->ctx,
+			(enum heif_compression_format) heif->compression,
+			&heif->encoder );
+	}
+
 	if( error.code ) {
 		if( error.code == heif_error_Unsupported_filetype ) 
 			vips_error( "heifsave", 
@@ -654,6 +686,13 @@ vips_foreign_save_heif_class_init( VipsForeignSaveHeifClass *class )
 		G_STRUCT_OFFSET( VipsForeignSaveHeif, speed ),
 		0, 9, 5 );
 
+	VIPS_ARG_ENUM( class, "encoder", 18,
+		_( "Encoder" ),
+		_( "Select encoder to use" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsForeignSaveHeif, selected_encoder ),
+		VIPS_TYPE_FOREIGN_HEIF_ENCODER,
+		VIPS_FOREIGN_HEIF_ENCODER_AUTO );
 }
 
 static void

libvips/include/vips/foreign.h

@@ -964,6 +964,28 @@ typedef enum {
 	VIPS_FOREIGN_HEIF_COMPRESSION_LAST
 } VipsForeignHeifCompression;
 
+/**
+ * VipsForeignHeifEncoder:
+ * @VIPS_FOREIGN_HEIF_ENCODER_AUTO: auto
+ * @VIPS_FOREIGN_HEIF_ENCODER_AOM: aom
+ * @VIPS_FOREIGN_HEIF_ENCODER_RAV1E: RAV1E
+ * @VIPS_FOREIGN_HEIF_ENCODER_SVT: SVT-AV1
+ * @VIPS_FOREIGN_HEIF_ENCODER_X265: x265
+ *
+ * The selected encoder to use.
+ * If libheif hasn't been compiled with the selected encoder,
+ * we will fallback to the default encoder for the compression format.
+ *
+ */
+typedef enum {
+	VIPS_FOREIGN_HEIF_ENCODER_AUTO,
+	VIPS_FOREIGN_HEIF_ENCODER_AOM,
+	VIPS_FOREIGN_HEIF_ENCODER_RAV1E,
+	VIPS_FOREIGN_HEIF_ENCODER_SVT,
+	VIPS_FOREIGN_HEIF_ENCODER_X265,
+	VIPS_FOREIGN_HEIF_ENCODER_LAST
+} VipsForeignHeifEncoder;
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus*/