[vlc-devel] [PATCH] png: add encoder
Tristan Matthews
le.businessman at gmail.com
Thu Feb 20 07:33:38 CET 2014
---
modules/codec/png.c | 200 ++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 194 insertions(+), 6 deletions(-)
diff --git a/modules/codec/png.c b/modules/codec/png.c
index b4d6ef4..6a20b82 100644
--- a/modules/codec/png.c
+++ b/modules/codec/png.c
@@ -33,12 +33,31 @@
#include <vlc_codec.h>
#include <png.h>
+/* PNG_SYS_COMMON_MEMBERS:
+ * members common to encoder and decoder descriptors
+ */
+#define PNG_SYS_COMMON_MEMBERS \
+/**@{*/ \
+ bool b_error; \
+ vlc_object_t *p_obj; \
+/**@}*/ \
+
+/*
+ * png common descriptor
+ */
+struct png_sys_t
+{
+ PNG_SYS_COMMON_MEMBERS
+};
+
+typedef struct png_sys_t png_sys_t;
+
/*****************************************************************************
* decoder_sys_t : png decoder descriptor
*****************************************************************************/
struct decoder_sys_t
{
- bool b_error;
+ PNG_SYS_COMMON_MEMBERS
};
/*****************************************************************************
@@ -49,6 +68,20 @@ static void CloseDecoder ( vlc_object_t * );
static picture_t *DecodeBlock ( decoder_t *, block_t ** );
+/*
+ * png encoder descriptor
+ */
+struct encoder_sys_t
+{
+ PNG_SYS_COMMON_MEMBERS
+ int i_blocksize;
+};
+
+static int OpenEncoder(vlc_object_t *);
+static void CloseEncoder(vlc_object_t *);
+
+static block_t *EncodeBlock(encoder_t *, picture_t *);
+
/*****************************************************************************
* Module descriptor
*****************************************************************************/
@@ -59,6 +92,14 @@ vlc_module_begin ()
set_capability( "decoder", 1000 )
set_callbacks( OpenDecoder, CloseDecoder )
add_shortcut( "png" )
+
+ /* encoder submodule */
+ add_submodule()
+ add_shortcut("png")
+ set_section(N_("Encoding"), NULL)
+ set_description(N_("PNG video encoder"))
+ set_capability("encoder", 1000)
+ set_callbacks(OpenEncoder, CloseEncoder)
vlc_module_end ()
/*****************************************************************************
@@ -78,6 +119,8 @@ static int OpenDecoder( vlc_object_t *p_this )
if( ( p_dec->p_sys = malloc(sizeof(decoder_sys_t)) ) == NULL )
return VLC_ENOMEM;
+ p_dec->p_sys->p_obj = p_this;
+
/* Set output properties */
p_dec->fmt_out.i_cat = VIDEO_ES;
p_dec->fmt_out.i_codec = VLC_CODEC_RGBA;
@@ -101,17 +144,40 @@ static void user_read( png_structp p_png, png_bytep data, png_size_t i_length )
p_block->i_buffer -= i_length;
}
+static void user_flush( png_structp p_png )
+{
+ /* noop */
+ (void) p_png;
+}
+
+static void user_write( png_structp p_png, png_bytep data, png_size_t i_length )
+{
+ block_t *p_block = (block_t *)png_get_io_ptr( p_png );
+ if( i_length > p_block->i_buffer ) {
+ char err_str[64];
+ snprintf( err_str, sizeof(err_str),
+ "block size %zu too small for %zu encoded bytes",
+ p_block->i_buffer, i_length );
+ png_error( p_png, err_str );
+ return;
+ }
+
+ memcpy( p_block->p_buffer, data, i_length );
+ p_block->p_buffer += i_length;
+ p_block->i_buffer -= i_length;
+}
+
static void user_error( png_structp p_png, png_const_charp error_msg )
{
- decoder_t *p_dec = (decoder_t *)png_get_error_ptr( p_png );
- p_dec->p_sys->b_error = true;
- msg_Err( p_dec, "%s", error_msg );
+ png_sys_t *p_sys = (png_sys_t *)png_get_error_ptr( p_png );
+ p_sys->b_error = true;
+ msg_Err( p_sys->p_obj, "%s", error_msg );
}
static void user_warning( png_structp p_png, png_const_charp warning_msg )
{
- decoder_t *p_dec = (decoder_t *)png_get_error_ptr( p_png );
- msg_Warn( p_dec, "%s", warning_msg );
+ png_sys_t *p_sys = (png_sys_t *)png_get_error_ptr( p_png );
+ msg_Warn( p_sys->p_obj, "%s", warning_msg );
}
/****************************************************************************
@@ -253,3 +319,125 @@ static void CloseDecoder( vlc_object_t *p_this )
free( p_sys );
}
+
+static int OpenEncoder(vlc_object_t *p_this)
+{
+ encoder_t *p_enc = (encoder_t *) p_this;
+
+ if( p_enc->fmt_out.i_codec != VLC_CODEC_PNG )
+ return VLC_EGENERIC;
+
+ /* Allocate the memory needed to store the encoder's structure */
+ p_enc->p_sys = malloc( sizeof(encoder_sys_t) );
+ if( p_enc->p_sys == NULL )
+ return VLC_ENOMEM;
+
+ p_enc->p_sys->p_obj = p_this;
+
+ p_enc->p_sys->i_blocksize = 3 * p_enc->fmt_in.video.i_visible_width *
+ p_enc->fmt_in.video.i_visible_height;
+
+ p_enc->fmt_in.i_codec = VLC_CODEC_RGB24;
+ p_enc->fmt_in.video.i_rmask = 0x000000ff;
+ p_enc->fmt_in.video.i_gmask = 0x0000ff00;
+ p_enc->fmt_in.video.i_bmask = 0x00ff0000;
+ p_enc->pf_encode_video = EncodeBlock;
+
+ return VLC_SUCCESS;
+}
+
+/*
+ * EncodeBlock
+ */
+static block_t *EncodeBlock(encoder_t *p_enc, picture_t *p_pic)
+{
+ encoder_sys_t *p_sys = p_enc->p_sys;
+
+ if( unlikely( !p_pic ) )
+ {
+ return NULL;
+ }
+
+ block_t *p_block = block_Alloc( p_sys->i_blocksize );
+ if( p_block == NULL )
+ {
+ return NULL;
+ }
+
+ png_structp p_png = png_create_write_struct( PNG_LIBPNG_VER_STRING, 0, 0, 0 );
+ if( p_png == NULL )
+ {
+ block_Release( p_block );
+ return NULL;
+ }
+
+ /* save buffer start */
+ uint8_t *p_start = p_block->p_buffer;
+ size_t i_start = p_block->i_buffer;
+
+ p_sys->b_error = false;
+ png_infop p_info = NULL;
+
+ /* libpng longjmp's there in case of error */
+ if( setjmp( png_jmpbuf( p_png ) ) )
+ goto error;
+
+ png_set_write_fn( p_png, p_block, user_write, user_flush );
+ png_set_error_fn( p_png, p_enc, user_error, user_warning );
+
+ p_info = png_create_info_struct( p_png );
+ if( p_info == NULL )
+ goto error;
+
+ png_infop p_end_info = png_create_info_struct( p_png );
+ if( p_end_info == NULL ) goto error;
+
+ const unsigned i_width = p_enc->fmt_in.video.i_visible_width;
+ const unsigned i_height = p_enc->fmt_in.video.i_visible_height;
+
+ png_set_IHDR( p_png, p_info,
+ i_width,
+ i_height,
+ 8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
+ PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT );
+ if( p_sys->b_error ) goto error;
+
+ png_write_info( p_png, p_info );
+ if( p_sys->b_error ) goto error;
+
+ /* Encode picture */
+
+ for( unsigned i = 0; i < i_height; i++ )
+ {
+ png_write_row( p_png, p_pic->p->p_pixels + (i_width * i * 3));
+ if( p_sys->b_error ) goto error;
+ }
+
+ png_write_end( p_png, p_end_info );
+ if( p_sys->b_error ) goto error;
+
+ png_destroy_write_struct( &p_png, &p_info );
+
+ /* restore original buffer position */
+ p_block->p_buffer = p_start;
+ p_block->i_buffer = i_start;
+ return p_block;
+
+ error:
+
+ png_destroy_write_struct( &p_png, p_info ? &p_info : NULL );
+
+ block_Release(p_block);
+ return NULL;
+}
+
+/*****************************************************************************
+ * CloseEncoder: png encoder destruction
+ *****************************************************************************/
+static void CloseEncoder( vlc_object_t *p_this )
+{
+ encoder_t *p_enc = (encoder_t *)p_this;
+ encoder_sys_t *p_sys = p_enc->p_sys;
+
+ free( p_sys );
+}
--
1.8.3.2
More information about the vlc-devel
mailing list