[vlc-devel] [PATCH] png: add encoder
Rafaël Carré
funman at videolan.org
Thu Feb 20 10:46:52 CET 2014
On 20 février 2014 07:33:38 CET, Tristan Matthews <le.businessman at gmail.com> wrote:
>---
>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 );
>+}
Lgtm, thanks
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