[FFmpeg-cvslog] png: add a standalone parser
Peter Holik
git at videolan.org
Tue Dec 17 18:09:28 CET 2013
ffmpeg | branch: master | Peter Holik <peter at holik.at> | Thu Dec 12 16:11:35 2013 +0100| [6fd99e78def3c795bdd0bc31f3ae0998d24bc94c] | committer: Vittorio Giovara
png: add a standalone parser
Useful for reading png images from a pipe.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6fd99e78def3c795bdd0bc31f3ae0998d24bc94c
---
Changelog | 1 +
libavcodec/Makefile | 1 +
libavcodec/allcodecs.c | 1 +
libavcodec/png_parser.c | 124 +++++++++++++++++++++++++++++++++++++++++++++++
libavcodec/version.h | 4 +-
5 files changed, 129 insertions(+), 2 deletions(-)
diff --git a/Changelog b/Changelog
index e7a8e44..6ec0357 100644
--- a/Changelog
+++ b/Changelog
@@ -51,6 +51,7 @@ version 10:
- support for decoding through VDPAU in avconv (the -hwaccel option)
- remove mp3_header_(de)compress bitstream filters
- stereoscopic 3d metadata handling
+- png standalone parser
version 9:
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 6dfb9a0..fb79c32 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -649,6 +649,7 @@ OBJS-$(CONFIG_MPEGAUDIO_PARSER) += mpegaudio_parser.o \
mpegaudiodecheader.o mpegaudiodata.o
OBJS-$(CONFIG_MPEGVIDEO_PARSER) += mpegvideo_parser.o \
mpeg12.o mpeg12data.o
+OBJS-$(CONFIG_PNG_PARSER) += png_parser.o
OBJS-$(CONFIG_PNM_PARSER) += pnm_parser.o pnm.o
OBJS-$(CONFIG_RV30_PARSER) += rv34_parser.o
OBJS-$(CONFIG_RV40_PARSER) += rv34_parser.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 044f585..8b2bdc1 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -464,6 +464,7 @@ void avcodec_register_all(void)
REGISTER_PARSER(MPEG4VIDEO, mpeg4video);
REGISTER_PARSER(MPEGAUDIO, mpegaudio);
REGISTER_PARSER(MPEGVIDEO, mpegvideo);
+ REGISTER_PARSER(PNG, png);
REGISTER_PARSER(PNM, pnm);
REGISTER_PARSER(RV30, rv30);
REGISTER_PARSER(RV40, rv40);
diff --git a/libavcodec/png_parser.c b/libavcodec/png_parser.c
new file mode 100644
index 0000000..00cbb82
--- /dev/null
+++ b/libavcodec/png_parser.c
@@ -0,0 +1,124 @@
+/*
+ * PNG parser
+ * Copyright (c) 2009 Peter Holik
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * PNG parser
+ */
+
+#include "libavutil/intreadwrite.h"
+#include "libavutil/common.h"
+
+#include "parser.h"
+
+#define PNG_SIGNATURE UINT64_C(0x89504e470d0a1a0a)
+#define MNG_SIGNATURE UINT64_C(0x8a4d4e470d0a1a0a)
+
+typedef struct PNGParseContext {
+ ParseContext pc;
+
+ int chunk_pos; ///< position inside current chunk
+ int chunk_length; ///< length of the current chunk
+ int remaining_size; ///< remaining size of the current chunk
+} PNGParseContext;
+
+static int png_parse(AVCodecParserContext *s, AVCodecContext *avctx,
+ const uint8_t **poutbuf, int *poutbuf_size,
+ const uint8_t *buf, int buf_size)
+{
+ PNGParseContext *ppc = s->priv_data;
+ int next = END_NOT_FOUND;
+ int i = 0;
+
+ *poutbuf_size = 0;
+ if (buf_size == 0)
+ return 0;
+
+ if (!ppc->pc.frame_start_found) {
+ uint64_t state64 = ppc->pc.state64;
+ for (; i < buf_size; i++) {
+ state64 = (state64 << 8) | buf[i];
+ if (state64 == PNG_SIGNATURE ||
+ state64 == MNG_SIGNATURE) {
+ i++;
+ ppc->pc.frame_start_found = 1;
+ break;
+ }
+ }
+ ppc->pc.state64 = state64;
+ } else if (ppc->remaining_size) {
+ i = FFMIN(ppc->remaining_size, buf_size);
+ ppc->remaining_size -= i;
+ if (ppc->remaining_size)
+ goto flush;
+ if (ppc->chunk_pos == -1) {
+ next = i;
+ goto flush;
+ }
+ }
+
+ for (; ppc->pc.frame_start_found && i < buf_size; i++) {
+ ppc->pc.state = (ppc->pc.state << 8) | buf[i];
+ if (ppc->chunk_pos == 3) {
+ ppc->chunk_length = AV_RL32(&ppc->pc.state);
+ if (ppc->chunk_length > 0x7fffffff) {
+ ppc->chunk_pos = ppc->pc.frame_start_found = 0;
+ goto flush;
+ }
+ ppc->chunk_length += 4;
+ } else if (ppc->chunk_pos == 7) {
+ if (ppc->chunk_length >= buf_size - i)
+ ppc->remaining_size = ppc->chunk_length - buf_size + i + 1;
+ if (AV_RB32(&ppc->pc.state) == MKTAG('I', 'E', 'N', 'D')) {
+ if (ppc->remaining_size)
+ ppc->chunk_pos = -1;
+ else
+ next = ppc->chunk_length + i + 1;
+ break;
+ } else {
+ ppc->chunk_pos = 0;
+ if (ppc->remaining_size)
+ break;
+ else
+ i += ppc->chunk_length;
+ continue;
+ }
+ }
+ ppc->chunk_pos++;
+ }
+
+flush:
+ if (ff_combine_frame(&ppc->pc, next, &buf, &buf_size) < 0)
+ return buf_size;
+
+ ppc->chunk_pos = ppc->pc.frame_start_found = 0;
+
+ *poutbuf = buf;
+ *poutbuf_size = buf_size;
+ return next;
+}
+
+AVCodecParser ff_png_parser = {
+ .codec_ids = { AV_CODEC_ID_PNG },
+ .priv_data_size = sizeof(PNGParseContext),
+ .parser_parse = png_parse,
+ .parser_close = ff_parse_close,
+};
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 2c3f2f2..c5a777b 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -27,8 +27,8 @@
*/
#define LIBAVCODEC_VERSION_MAJOR 55
-#define LIBAVCODEC_VERSION_MINOR 28
-#define LIBAVCODEC_VERSION_MICRO 1
+#define LIBAVCODEC_VERSION_MINOR 29
+#define LIBAVCODEC_VERSION_MICRO 0
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
LIBAVCODEC_VERSION_MINOR, \
More information about the ffmpeg-cvslog
mailing list