gstreamer/gst-libs/gst/codecparsers/nalutils.h
Wangfei 55db6413d7 h26[45]parser: Fix emulation prevention byte detection
Add a separate epb_cache variable to the codecparser NalReader to
detect Emulation Prevention Bytes separately from the main bit cache.

This fixes problems where the existing logic can mistakenly detect
multiple EPB with a sequence like: 0x00 0x00 0x03 0x00 0x03. In that
case, the 5th byte should not be regarded as an EPB.
2019-08-19 05:01:24 +00:00

184 lines
5 KiB
C

/* Gstreamer
* Copyright (C) <2011> Intel Corporation
* Copyright (C) <2011> Collabora Ltd.
* Copyright (C) <2011> Thibault Saunier <thibault.saunier@collabora.com>
*
* Some bits C-c,C-v'ed and s/4/3 from h264parse and videoparsers/h264parse.c:
* Copyright (C) <2010> Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>
* Copyright (C) <2010> Collabora Multimedia
* Copyright (C) <2010> Nokia Corporation
*
* (C) 2005 Michal Benes <michal.benes@itonis.tv>
* (C) 2008 Wim Taymans <wim.taymans@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* 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.
*/
/**
* Common code for NAL parsing from h264 and h265 parsers.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <gst/base/gstbytereader.h>
#include <gst/base/gstbitreader.h>
#include <string.h>
guint ceil_log2 (guint32 v);
typedef struct
{
const guint8 *data;
guint size;
guint n_epb; /* Number of emulation prevention bytes */
guint byte; /* Byte position */
guint bits_in_cache; /* bitpos in the cache of next bit */
guint8 first_byte;
guint32 epb_cache; /* cache 3 bytes to check emulation prevention bytes */
guint64 cache; /* cached bytes */
} NalReader;
G_GNUC_INTERNAL
void nal_reader_init (NalReader * nr, const guint8 * data, guint size);
G_GNUC_INTERNAL
gboolean nal_reader_read (NalReader * nr, guint nbits);
G_GNUC_INTERNAL
gboolean nal_reader_skip (NalReader * nr, guint nbits);
G_GNUC_INTERNAL
gboolean nal_reader_skip_long (NalReader * nr, guint nbits);
G_GNUC_INTERNAL
guint nal_reader_get_pos (const NalReader * nr);
G_GNUC_INTERNAL
guint nal_reader_get_remaining (const NalReader * nr);
G_GNUC_INTERNAL
guint nal_reader_get_epb_count (const NalReader * nr);
G_GNUC_INTERNAL
gboolean nal_reader_is_byte_aligned (NalReader * nr);
G_GNUC_INTERNAL
gboolean nal_reader_has_more_data (NalReader * nr);
#define NAL_READER_READ_BITS_H(bits) \
G_GNUC_INTERNAL \
gboolean nal_reader_get_bits_uint##bits (NalReader *nr, guint##bits *val, guint nbits)
NAL_READER_READ_BITS_H (8);
NAL_READER_READ_BITS_H (16);
NAL_READER_READ_BITS_H (32);
#define NAL_READER_PEEK_BITS_H(bits) \
G_GNUC_INTERNAL \
gboolean nal_reader_peek_bits_uint##bits (const NalReader *nr, guint##bits *val, guint nbits)
NAL_READER_PEEK_BITS_H (8);
G_GNUC_INTERNAL
gboolean nal_reader_get_ue (NalReader * nr, guint32 * val);
G_GNUC_INTERNAL
gboolean nal_reader_get_se (NalReader * nr, gint32 * val);
#define CHECK_ALLOWED_MAX(val, max) { \
if (val > max) { \
GST_WARNING ("value greater than max. value: %d, max %d", \
val, max); \
goto error; \
} \
}
#define CHECK_ALLOWED(val, min, max) { \
if (val < min || val > max) { \
GST_WARNING ("value not in allowed range. value: %d, range %d-%d", \
val, min, max); \
goto error; \
} \
}
#define READ_UINT8(nr, val, nbits) { \
if (!nal_reader_get_bits_uint8 (nr, &val, nbits)) { \
GST_WARNING ("failed to read uint8, nbits: %d", nbits); \
goto error; \
} \
}
#define READ_UINT16(nr, val, nbits) { \
if (!nal_reader_get_bits_uint16 (nr, &val, nbits)) { \
GST_WARNING ("failed to read uint16, nbits: %d", nbits); \
goto error; \
} \
}
#define READ_UINT32(nr, val, nbits) { \
if (!nal_reader_get_bits_uint32 (nr, &val, nbits)) { \
GST_WARNING ("failed to read uint32, nbits: %d", nbits); \
goto error; \
} \
}
#define READ_UINT64(nr, val, nbits) { \
if (!nal_reader_get_bits_uint64 (nr, &val, nbits)) { \
GST_WARNING ("failed to read uint32, nbits: %d", nbits); \
goto error; \
} \
}
#define READ_UE(nr, val) { \
if (!nal_reader_get_ue (nr, &val)) { \
GST_WARNING ("failed to read UE"); \
goto error; \
} \
}
#define READ_UE_ALLOWED(nr, val, min, max) { \
guint32 tmp; \
READ_UE (nr, tmp); \
CHECK_ALLOWED (tmp, min, max); \
val = tmp; \
}
#define READ_UE_MAX(nr, val, max) { \
guint32 tmp; \
READ_UE (nr, tmp); \
CHECK_ALLOWED_MAX (tmp, max); \
val = tmp; \
}
#define READ_SE(nr, val) { \
if (!nal_reader_get_se (nr, &val)) { \
GST_WARNING ("failed to read SE"); \
goto error; \
} \
}
#define READ_SE_ALLOWED(nr, val, min, max) { \
gint32 tmp; \
READ_SE (nr, tmp); \
CHECK_ALLOWED (tmp, min, max); \
val = tmp; \
}
G_GNUC_INTERNAL
gint scan_for_start_codes (const guint8 * data, guint size);