gstreamer/ext/libpng/gstpngdec.c
Tim-Philipp Müller bf56fd97b6 Use g_memdup2() where available and add fallback for older GLib versions
- png: alloc size variable is a png type that's always 32-bit
- vpx: alloc size based on existing allocation
- wavpack: alloc size based on existing allocation
- icles: gdkpixbufoverlay: trusted and hard-coded input data
- rtp tests: rtp-payloading, vp8, vp9, h264, h265: trusted and/or static input data

g_memdup() is deprecated since GLib 2.68 and we want to avoid
deprecation warnings with recent versions of GLib.

Also use gst_buffer_new_memdup() instead of _wrapped(g_memdup(),..)

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/993>
2021-06-02 17:34:38 +01:00

711 lines
20 KiB
C

/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
* Copyright (C) 2012 Collabora Ltd.
* Author : Edward Hervey <edward@collabora.com>
* Copyright (C) 2013 Collabora Ltd.
* Author : Sebastian Dröge <sebastian.droege@collabora.co.uk>
* Olivier Crete <olivier.crete@collabora.com>
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
/**
* SECTION:element-pngdec
* @title: pngdec
*
* Decodes png images. If there is no framerate set on sink caps, it sends EOS
* after the first picture.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gstpngdec.h"
#include <stdlib.h>
#include <string.h>
#include <gst/base/gstbytereader.h>
#include <gst/video/video.h>
#include <gst/video/gstvideometa.h>
#include <gst/video/gstvideopool.h>
#include <gst/gst-i18n-plugin.h>
GST_DEBUG_CATEGORY_STATIC (pngdec_debug);
#define GST_CAT_DEFAULT pngdec_debug
static gboolean gst_pngdec_libpng_init (GstPngDec * pngdec);
static GstFlowReturn gst_pngdec_caps_create_and_set (GstPngDec * pngdec);
static gboolean gst_pngdec_start (GstVideoDecoder * decoder);
static gboolean gst_pngdec_stop (GstVideoDecoder * decoder);
static gboolean gst_pngdec_flush (GstVideoDecoder * decoder);
static gboolean gst_pngdec_set_format (GstVideoDecoder * Decoder,
GstVideoCodecState * state);
static GstFlowReturn gst_pngdec_parse (GstVideoDecoder * decoder,
GstVideoCodecFrame * frame, GstAdapter * adapter, gboolean at_eos);
static GstFlowReturn gst_pngdec_handle_frame (GstVideoDecoder * decoder,
GstVideoCodecFrame * frame);
static gboolean gst_pngdec_decide_allocation (GstVideoDecoder * decoder,
GstQuery * query);
static gboolean gst_pngdec_sink_event (GstVideoDecoder * bdec,
GstEvent * event);
#define parent_class gst_pngdec_parent_class
G_DEFINE_TYPE (GstPngDec, gst_pngdec, GST_TYPE_VIDEO_DECODER);
GST_ELEMENT_REGISTER_DEFINE (pngdec, "pngdec", GST_RANK_PRIMARY,
GST_TYPE_PNGDEC);
static GstStaticPadTemplate gst_pngdec_src_pad_template =
GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE
("{ RGBA, RGB, ARGB64, GRAY8, GRAY16_BE }"))
);
static GstStaticPadTemplate gst_pngdec_sink_pad_template =
GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("image/png")
);
static void
gst_pngdec_class_init (GstPngDecClass * klass)
{
GstElementClass *element_class = (GstElementClass *) klass;
GstVideoDecoderClass *vdec_class = (GstVideoDecoderClass *) klass;
gst_element_class_add_static_pad_template (element_class,
&gst_pngdec_src_pad_template);
gst_element_class_add_static_pad_template (element_class,
&gst_pngdec_sink_pad_template);
gst_element_class_set_static_metadata (element_class, "PNG image decoder",
"Codec/Decoder/Image", "Decode a png video frame to a raw image",
"Wim Taymans <wim@fluendo.com>");
vdec_class->start = gst_pngdec_start;
vdec_class->stop = gst_pngdec_stop;
vdec_class->flush = gst_pngdec_flush;
vdec_class->set_format = gst_pngdec_set_format;
vdec_class->parse = gst_pngdec_parse;
vdec_class->handle_frame = gst_pngdec_handle_frame;
vdec_class->decide_allocation = gst_pngdec_decide_allocation;
vdec_class->sink_event = gst_pngdec_sink_event;
GST_DEBUG_CATEGORY_INIT (pngdec_debug, "pngdec", 0, "PNG image decoder");
}
static void
gst_pngdec_init (GstPngDec * pngdec)
{
pngdec->png = NULL;
pngdec->info = NULL;
pngdec->endinfo = NULL;
pngdec->color_type = -1;
pngdec->image_ready = FALSE;
pngdec->read_data = 0;
gst_video_decoder_set_use_default_pad_acceptcaps (GST_VIDEO_DECODER_CAST
(pngdec), TRUE);
GST_PAD_SET_ACCEPT_TEMPLATE (GST_VIDEO_DECODER_SINK_PAD (pngdec));
}
static void
user_error_fn (png_structp png_ptr, png_const_charp error_msg)
{
GST_ERROR ("%s", error_msg);
}
static void
user_warning_fn (png_structp png_ptr, png_const_charp warning_msg)
{
GST_WARNING ("%s", warning_msg);
}
static void
user_info_callback (png_structp png_ptr, png_infop info)
{
GstPngDec *pngdec = NULL;
GstFlowReturn ret;
GST_LOG ("info ready");
pngdec = GST_PNGDEC (png_get_io_ptr (png_ptr));
/* Generate the caps and configure */
ret = gst_pngdec_caps_create_and_set (pngdec);
if (ret != GST_FLOW_OK) {
goto beach;
}
/* Allocate output buffer */
ret =
gst_video_decoder_allocate_output_frame (GST_VIDEO_DECODER (pngdec),
pngdec->current_frame);
if (G_UNLIKELY (ret != GST_FLOW_OK))
GST_DEBUG_OBJECT (pngdec, "failed to acquire buffer");
beach:
pngdec->ret = ret;
}
static gboolean
gst_pngdec_set_format (GstVideoDecoder * decoder, GstVideoCodecState * state)
{
GstPngDec *pngdec = (GstPngDec *) decoder;
if (pngdec->input_state)
gst_video_codec_state_unref (pngdec->input_state);
pngdec->input_state = gst_video_codec_state_ref (state);
/* We'll set format later on */
return TRUE;
}
static void
user_endrow_callback (png_structp png_ptr, png_bytep new_row,
png_uint_32 row_num, int pass)
{
GstPngDec *pngdec = NULL;
pngdec = GST_PNGDEC (png_get_io_ptr (png_ptr));
/* If buffer_out doesn't exist, it means buffer_alloc failed, which
* will already have set the return code */
if (new_row && GST_IS_BUFFER (pngdec->current_frame->output_buffer)) {
GstVideoFrame frame;
GstBuffer *buffer = pngdec->current_frame->output_buffer;
size_t offset;
guint8 *data;
if (!gst_video_frame_map (&frame, &pngdec->output_state->info, buffer,
GST_MAP_WRITE)) {
pngdec->ret = GST_FLOW_ERROR;
return;
}
data = GST_VIDEO_FRAME_COMP_DATA (&frame, 0);
offset = row_num * GST_VIDEO_FRAME_COMP_STRIDE (&frame, 0);
GST_LOG ("got row %u at pass %d, copying in buffer %p at offset %"
G_GSIZE_FORMAT, (guint) row_num, pass,
pngdec->current_frame->output_buffer, offset);
png_progressive_combine_row (pngdec->png, data + offset, new_row);
gst_video_frame_unmap (&frame);
pngdec->ret = GST_FLOW_OK;
} else
pngdec->ret = GST_FLOW_OK;
}
static void
user_end_callback (png_structp png_ptr, png_infop info)
{
GstPngDec *pngdec = NULL;
pngdec = GST_PNGDEC (png_get_io_ptr (png_ptr));
GST_LOG_OBJECT (pngdec, "and we are done reading this image");
if (!pngdec->current_frame->output_buffer)
return;
gst_buffer_unmap (pngdec->current_frame->input_buffer,
&pngdec->current_frame_map);
pngdec->ret =
gst_video_decoder_finish_frame (GST_VIDEO_DECODER (pngdec),
pngdec->current_frame);
pngdec->image_ready = TRUE;
}
static GstFlowReturn
gst_pngdec_caps_create_and_set (GstPngDec * pngdec)
{
GstFlowReturn ret = GST_FLOW_OK;
gint bpc = 0, color_type;
png_uint_32 width, height;
GstVideoFormat format = GST_VIDEO_FORMAT_UNKNOWN;
g_return_val_if_fail (GST_IS_PNGDEC (pngdec), GST_FLOW_ERROR);
/* Get bits per channel */
bpc = png_get_bit_depth (pngdec->png, pngdec->info);
/* Get Color type */
color_type = png_get_color_type (pngdec->png, pngdec->info);
/* Add alpha channel if 16-bit depth, but not for GRAY images */
if ((bpc > 8) && (color_type != PNG_COLOR_TYPE_GRAY)) {
png_set_add_alpha (pngdec->png, 0xffff, PNG_FILLER_BEFORE);
png_set_swap (pngdec->png);
}
#if 0
/* We used to have this HACK to reverse the outgoing bytes, but the problem
* that originally required the hack seems to have been in videoconvert's
* RGBA descriptions. It doesn't seem needed now that's fixed, but might
* still be needed on big-endian systems, I'm not sure. J.S. 6/7/2007 */
if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
png_set_bgr (pngdec->png);
#endif
/* Gray scale with alpha channel converted to RGB */
if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
GST_LOG_OBJECT (pngdec,
"converting grayscale png with alpha channel to RGB");
png_set_gray_to_rgb (pngdec->png);
}
/* Gray scale converted to upscaled to 8 bits */
if ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) ||
(color_type == PNG_COLOR_TYPE_GRAY)) {
if (bpc < 8) { /* Convert to 8 bits */
GST_LOG_OBJECT (pngdec, "converting grayscale image to 8 bits");
#if PNG_LIBPNG_VER < 10400
png_set_gray_1_2_4_to_8 (pngdec->png);
#else
png_set_expand_gray_1_2_4_to_8 (pngdec->png);
#endif
}
}
/* Palette converted to RGB */
if (color_type == PNG_COLOR_TYPE_PALETTE) {
GST_LOG_OBJECT (pngdec, "converting palette png to RGB");
png_set_palette_to_rgb (pngdec->png);
}
png_set_interlace_handling (pngdec->png);
/* Update the info structure */
png_read_update_info (pngdec->png, pngdec->info);
/* Get IHDR header again after transformation settings */
png_get_IHDR (pngdec->png, pngdec->info, &width, &height,
&bpc, &pngdec->color_type, NULL, NULL, NULL);
GST_LOG_OBJECT (pngdec, "this is a %dx%d PNG image", (gint) width,
(gint) height);
switch (pngdec->color_type) {
case PNG_COLOR_TYPE_RGB:
GST_LOG_OBJECT (pngdec, "we have no alpha channel, depth is 24 bits");
if (bpc == 8)
format = GST_VIDEO_FORMAT_RGB;
break;
case PNG_COLOR_TYPE_RGB_ALPHA:
GST_LOG_OBJECT (pngdec,
"we have an alpha channel, depth is 32 or 64 bits");
if (bpc == 8)
format = GST_VIDEO_FORMAT_RGBA;
else if (bpc == 16)
format = GST_VIDEO_FORMAT_ARGB64;
break;
case PNG_COLOR_TYPE_GRAY:
GST_LOG_OBJECT (pngdec,
"We have an gray image, depth is 8 or 16 (be) bits");
if (bpc == 8)
format = GST_VIDEO_FORMAT_GRAY8;
else if (bpc == 16)
format = GST_VIDEO_FORMAT_GRAY16_BE;
break;
default:
break;
}
if (format == GST_VIDEO_FORMAT_UNKNOWN) {
GST_ELEMENT_ERROR (pngdec, STREAM, NOT_IMPLEMENTED, (NULL),
("pngdec does not support this color type"));
ret = GST_FLOW_NOT_SUPPORTED;
goto beach;
}
/* Check if output state changed */
if (pngdec->output_state) {
GstVideoInfo *info = &pngdec->output_state->info;
if (width == GST_VIDEO_INFO_WIDTH (info) &&
height == GST_VIDEO_INFO_HEIGHT (info) &&
GST_VIDEO_INFO_FORMAT (info) == format) {
goto beach;
}
gst_video_codec_state_unref (pngdec->output_state);
}
#ifdef HAVE_LIBPNG_1_5
if ((pngdec->color_type & PNG_COLOR_MASK_COLOR)
&& !(pngdec->color_type & PNG_COLOR_MASK_PALETTE)
&& png_get_valid (pngdec->png, pngdec->info, PNG_INFO_iCCP)) {
png_charp icc_name;
png_bytep icc_profile;
int icc_compression_type;
png_uint_32 icc_proflen = 0;
png_uint_32 ret = png_get_iCCP (pngdec->png, pngdec->info, &icc_name,
&icc_compression_type, &icc_profile, &icc_proflen);
if ((ret & PNG_INFO_iCCP)) {
gpointer gst_icc_prof = g_memdup2 (icc_profile, icc_proflen);
GstBuffer *tagbuffer = NULL;
GstSample *tagsample = NULL;
GstTagList *taglist = NULL;
GstStructure *info = NULL;
GstCaps *caps;
GST_DEBUG_OBJECT (pngdec, "extracted ICC profile '%s' length=%i",
icc_name, (guint32) icc_proflen);
tagbuffer = gst_buffer_new_wrapped (gst_icc_prof, icc_proflen);
caps = gst_caps_new_empty_simple ("application/vnd.iccprofile");
info = gst_structure_new_empty ("application/vnd.iccprofile");
if (icc_name)
gst_structure_set (info, "icc-name", G_TYPE_STRING, icc_name, NULL);
tagsample = gst_sample_new (tagbuffer, caps, NULL, info);
gst_buffer_unref (tagbuffer);
gst_caps_unref (caps);
taglist = gst_tag_list_new_empty ();
gst_tag_list_add (taglist, GST_TAG_MERGE_APPEND, GST_TAG_ATTACHMENT,
tagsample, NULL);
gst_sample_unref (tagsample);
gst_video_decoder_merge_tags (GST_VIDEO_DECODER (pngdec), taglist,
GST_TAG_MERGE_APPEND);
gst_tag_list_unref (taglist);
}
}
#endif
pngdec->output_state =
gst_video_decoder_set_output_state (GST_VIDEO_DECODER (pngdec), format,
width, height, pngdec->input_state);
gst_video_decoder_negotiate (GST_VIDEO_DECODER (pngdec));
GST_DEBUG ("Final %d %d", GST_VIDEO_INFO_WIDTH (&pngdec->output_state->info),
GST_VIDEO_INFO_HEIGHT (&pngdec->output_state->info));
beach:
return ret;
}
static GstFlowReturn
gst_pngdec_handle_frame (GstVideoDecoder * decoder, GstVideoCodecFrame * frame)
{
GstPngDec *pngdec = (GstPngDec *) decoder;
GstFlowReturn ret = GST_FLOW_OK;
GST_LOG_OBJECT (pngdec, "Got buffer, size=%u",
(guint) gst_buffer_get_size (frame->input_buffer));
/* Let libpng come back here on error */
if (setjmp (png_jmpbuf (pngdec->png))) {
GST_WARNING_OBJECT (pngdec, "error during decoding");
ret = GST_FLOW_ERROR;
goto beach;
}
pngdec->current_frame = frame;
/* Progressive loading of the PNG image */
if (!gst_buffer_map (frame->input_buffer, &pngdec->current_frame_map,
GST_MAP_READ)) {
GST_WARNING_OBJECT (pngdec, "Failed to map input buffer");
ret = GST_FLOW_ERROR;
goto beach;
}
png_process_data (pngdec->png, pngdec->info,
pngdec->current_frame_map.data, pngdec->current_frame_map.size);
if (pngdec->image_ready) {
/* Reset ourselves for the next frame */
gst_pngdec_flush (decoder);
GST_LOG_OBJECT (pngdec, "setting up callbacks for next frame");
png_set_progressive_read_fn (pngdec->png, pngdec,
user_info_callback, user_endrow_callback, user_end_callback);
pngdec->image_ready = FALSE;
} else {
/* An error happened and we have to unmap */
gst_buffer_unmap (pngdec->current_frame->input_buffer,
&pngdec->current_frame_map);
}
ret = pngdec->ret;
beach:
return ret;
}
/* Based on pngparse */
#define PNG_SIGNATURE G_GUINT64_CONSTANT (0x89504E470D0A1A0A)
static GstFlowReturn
gst_pngdec_parse (GstVideoDecoder * decoder, GstVideoCodecFrame * frame,
GstAdapter * adapter, gboolean at_eos)
{
gsize toadd = 0;
GstByteReader reader;
gconstpointer data;
guint64 signature;
gsize size;
GstPngDec *pngdec = (GstPngDec *) decoder;
GST_VIDEO_CODEC_FRAME_SET_SYNC_POINT (frame);
/* FIXME : The overhead of using scan_uint32 is massive */
size = gst_adapter_available (adapter);
GST_DEBUG ("Parsing PNG image data (%" G_GSIZE_FORMAT " bytes)", size);
if (size < 8)
goto need_more_data;
data = gst_adapter_map (adapter, size);
gst_byte_reader_init (&reader, data, size);
if (pngdec->read_data == 0) {
if (!gst_byte_reader_peek_uint64_be (&reader, &signature))
goto need_more_data;
if (signature != PNG_SIGNATURE) {
for (;;) {
guint offset;
offset = gst_byte_reader_masked_scan_uint32 (&reader, 0xffffffff,
0x89504E47, 0, gst_byte_reader_get_remaining (&reader));
if (offset == -1) {
gst_adapter_flush (adapter,
gst_byte_reader_get_remaining (&reader) - 4);
goto need_more_data;
}
if (!gst_byte_reader_skip (&reader, offset))
goto need_more_data;
if (!gst_byte_reader_peek_uint64_be (&reader, &signature))
goto need_more_data;
if (signature == PNG_SIGNATURE) {
/* We're skipping, go out, we'll be back */
gst_adapter_flush (adapter, gst_byte_reader_get_pos (&reader));
goto need_more_data;
}
if (!gst_byte_reader_skip (&reader, 4))
goto need_more_data;
}
}
pngdec->read_data = 8;
}
if (!gst_byte_reader_skip (&reader, pngdec->read_data))
goto need_more_data;
for (;;) {
guint32 length;
guint32 code;
if (!gst_byte_reader_get_uint32_be (&reader, &length))
goto need_more_data;
if (!gst_byte_reader_get_uint32_le (&reader, &code))
goto need_more_data;
if (!gst_byte_reader_skip (&reader, length + 4))
goto need_more_data;
if (code == GST_MAKE_FOURCC ('I', 'E', 'N', 'D')) {
/* Have complete frame */
toadd = gst_byte_reader_get_pos (&reader);
GST_DEBUG_OBJECT (decoder, "Have complete frame of size %" G_GSIZE_FORMAT,
toadd);
pngdec->read_data = 0;
goto have_full_frame;
} else
pngdec->read_data += length + 12;
}
g_assert_not_reached ();
return GST_FLOW_ERROR;
need_more_data:
return GST_VIDEO_DECODER_FLOW_NEED_DATA;
have_full_frame:
if (toadd)
gst_video_decoder_add_to_frame (decoder, toadd);
return gst_video_decoder_have_frame (decoder);
}
static gboolean
gst_pngdec_decide_allocation (GstVideoDecoder * bdec, GstQuery * query)
{
GstBufferPool *pool = NULL;
GstStructure *config;
if (!GST_VIDEO_DECODER_CLASS (parent_class)->decide_allocation (bdec, query))
return FALSE;
if (gst_query_get_n_allocation_pools (query) > 0)
gst_query_parse_nth_allocation_pool (query, 0, &pool, NULL, NULL, NULL);
if (pool == NULL)
return FALSE;
config = gst_buffer_pool_get_config (pool);
if (gst_query_find_allocation_meta (query, GST_VIDEO_META_API_TYPE, NULL)) {
gst_buffer_pool_config_add_option (config,
GST_BUFFER_POOL_OPTION_VIDEO_META);
}
gst_buffer_pool_set_config (pool, config);
gst_object_unref (pool);
return TRUE;
}
static gboolean
gst_pngdec_sink_event (GstVideoDecoder * bdec, GstEvent * event)
{
const GstSegment *segment;
if (GST_EVENT_TYPE (event) != GST_EVENT_SEGMENT)
goto done;
gst_event_parse_segment (event, &segment);
if (segment->format == GST_FORMAT_TIME)
gst_video_decoder_set_packetized (bdec, TRUE);
else
gst_video_decoder_set_packetized (bdec, FALSE);
done:
return GST_VIDEO_DECODER_CLASS (parent_class)->sink_event (bdec, event);
}
static gboolean
gst_pngdec_libpng_init (GstPngDec * pngdec)
{
g_return_val_if_fail (GST_IS_PNGDEC (pngdec), FALSE);
GST_LOG ("init libpng structures");
/* initialize png struct stuff */
pngdec->png = png_create_read_struct (PNG_LIBPNG_VER_STRING,
(png_voidp) NULL, user_error_fn, user_warning_fn);
if (pngdec->png == NULL)
goto init_failed;
pngdec->info = png_create_info_struct (pngdec->png);
if (pngdec->info == NULL)
goto info_failed;
pngdec->endinfo = png_create_info_struct (pngdec->png);
if (pngdec->endinfo == NULL)
goto endinfo_failed;
png_set_progressive_read_fn (pngdec->png, pngdec,
user_info_callback, user_endrow_callback, user_end_callback);
return TRUE;
/* ERRORS */
init_failed:
{
GST_ELEMENT_ERROR (pngdec, LIBRARY, INIT, (NULL),
("Failed to initialize png structure"));
return FALSE;
}
info_failed:
{
GST_ELEMENT_ERROR (pngdec, LIBRARY, INIT, (NULL),
("Failed to initialize info structure"));
return FALSE;
}
endinfo_failed:
{
GST_ELEMENT_ERROR (pngdec, LIBRARY, INIT, (NULL),
("Failed to initialize endinfo structure"));
return FALSE;
}
}
static void
gst_pngdec_libpng_clear (GstPngDec * pngdec)
{
png_infopp info = NULL, endinfo = NULL;
GST_LOG ("cleaning up libpng structures");
if (pngdec->info) {
info = &pngdec->info;
}
if (pngdec->endinfo) {
endinfo = &pngdec->endinfo;
}
if (pngdec->png) {
png_destroy_read_struct (&(pngdec->png), info, endinfo);
pngdec->png = NULL;
pngdec->info = NULL;
pngdec->endinfo = NULL;
}
pngdec->color_type = -1;
pngdec->read_data = 0;
}
static gboolean
gst_pngdec_start (GstVideoDecoder * decoder)
{
GstPngDec *pngdec = (GstPngDec *) decoder;
gst_video_decoder_set_packetized (GST_VIDEO_DECODER (pngdec), FALSE);
gst_pngdec_libpng_init (pngdec);
return TRUE;
}
static gboolean
gst_pngdec_stop (GstVideoDecoder * decoder)
{
GstPngDec *pngdec = (GstPngDec *) decoder;
gst_pngdec_libpng_clear (pngdec);
if (pngdec->input_state) {
gst_video_codec_state_unref (pngdec->input_state);
pngdec->input_state = NULL;
}
if (pngdec->output_state) {
gst_video_codec_state_unref (pngdec->output_state);
pngdec->output_state = NULL;
}
return TRUE;
}
/* Clean up the libpng structures */
static gboolean
gst_pngdec_flush (GstVideoDecoder * decoder)
{
gst_pngdec_libpng_clear ((GstPngDec *) decoder);
gst_pngdec_libpng_init ((GstPngDec *) decoder);
return TRUE;
}