mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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97ebaa0bc1
Move ceil_log2 from nalutils.* to gstutils.* Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5888>
547 lines
12 KiB
C
547 lines
12 KiB
C
/* Gstreamer
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* Copyright (C) <2011> Intel Corporation
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* Copyright (C) <2011> Collabora Ltd.
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* Copyright (C) <2011> Thibault Saunier <thibault.saunier@collabora.com>
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*
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* Some bits C-c,C-v'ed and s/4/3 from h264parse and videoparsers/h264parse.c:
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* Copyright (C) <2010> Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>
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* Copyright (C) <2010> Collabora Multimedia
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* Copyright (C) <2010> Nokia Corporation
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*
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* (C) 2005 Michal Benes <michal.benes@itonis.tv>
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* (C) 2008 Wim Taymans <wim.taymans@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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/*
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* Common code for NAL parsing from h264 and h265 parsers.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include "nalutils.h"
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#include <string.h>
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/****** Nal parser ******/
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void
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nal_reader_init (NalReader * nr, const guint8 * data, guint size)
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{
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nr->data = data;
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nr->size = size;
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nr->n_epb = 0;
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nr->byte = 0;
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nr->bits_in_cache = 0;
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/* fill with something other than 0 to detect emulation prevention bytes */
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nr->first_byte = 0xff;
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nr->epb_cache = 0xff;
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nr->cache = 0xff;
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}
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gboolean
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nal_reader_read (NalReader * nr, guint nbits)
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{
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if (G_UNLIKELY (nr->byte * 8 + (nbits - nr->bits_in_cache) > nr->size * 8)) {
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GST_DEBUG ("Can not read %u bits, bits in cache %u, Byte * 8 %u, size in "
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"bits %u", nbits, nr->bits_in_cache, nr->byte * 8, nr->size * 8);
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return FALSE;
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}
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while (nr->bits_in_cache < nbits) {
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guint8 byte;
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next_byte:
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if (G_UNLIKELY (nr->byte >= nr->size))
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return FALSE;
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byte = nr->data[nr->byte++];
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nr->epb_cache = (nr->epb_cache << 8) | byte;
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/* check if the byte is a emulation_prevention_three_byte */
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if ((nr->epb_cache & 0xffffff) == 0x3) {
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nr->n_epb++;
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goto next_byte;
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}
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nr->cache = (nr->cache << 8) | nr->first_byte;
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nr->first_byte = byte;
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nr->bits_in_cache += 8;
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}
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return TRUE;
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}
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/* Skips the specified amount of bits. This is only suitable to a
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cacheable number of bits */
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gboolean
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nal_reader_skip (NalReader * nr, guint nbits)
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{
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g_assert (nbits <= 8 * sizeof (nr->cache));
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if (G_UNLIKELY (!nal_reader_read (nr, nbits)))
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return FALSE;
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nr->bits_in_cache -= nbits;
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return TRUE;
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}
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/* Generic version to skip any number of bits */
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gboolean
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nal_reader_skip_long (NalReader * nr, guint nbits)
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{
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/* Leave out enough bits in the cache once we are finished */
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const guint skip_size = 4 * sizeof (nr->cache);
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guint remaining = nbits;
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nbits %= skip_size;
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while (remaining > 0) {
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if (!nal_reader_skip (nr, nbits))
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return FALSE;
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remaining -= nbits;
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nbits = skip_size;
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}
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return TRUE;
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}
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guint
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nal_reader_get_pos (const NalReader * nr)
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{
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return nr->byte * 8 - nr->bits_in_cache;
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}
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guint
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nal_reader_get_remaining (const NalReader * nr)
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{
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return (nr->size - nr->byte) * 8 + nr->bits_in_cache;
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}
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guint
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nal_reader_get_epb_count (const NalReader * nr)
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{
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return nr->n_epb;
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}
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#define NAL_READER_READ_BITS(bits) \
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gboolean \
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nal_reader_get_bits_uint##bits (NalReader *nr, guint##bits *val, guint nbits) \
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{ \
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guint shift; \
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\
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if (!nal_reader_read (nr, nbits)) \
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return FALSE; \
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\
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/* bring the required bits down and truncate */ \
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shift = nr->bits_in_cache - nbits; \
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*val = nr->first_byte >> shift; \
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\
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*val |= nr->cache << (8 - shift); \
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/* mask out required bits */ \
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if (nbits < bits) \
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*val &= ((guint##bits)1 << nbits) - 1; \
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\
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nr->bits_in_cache = shift; \
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\
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return TRUE; \
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} \
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NAL_READER_READ_BITS (8);
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NAL_READER_READ_BITS (16);
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NAL_READER_READ_BITS (32);
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#define NAL_READER_PEEK_BITS(bits) \
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gboolean \
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nal_reader_peek_bits_uint##bits (const NalReader *nr, guint##bits *val, guint nbits) \
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{ \
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NalReader tmp; \
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\
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tmp = *nr; \
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return nal_reader_get_bits_uint##bits (&tmp, val, nbits); \
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}
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NAL_READER_PEEK_BITS (8);
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gboolean
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nal_reader_get_ue (NalReader * nr, guint32 * val)
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{
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guint i = 0;
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guint8 bit;
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guint32 value;
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if (G_UNLIKELY (!nal_reader_get_bits_uint8 (nr, &bit, 1)))
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return FALSE;
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while (bit == 0) {
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i++;
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if (G_UNLIKELY (!nal_reader_get_bits_uint8 (nr, &bit, 1)))
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return FALSE;
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}
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if (G_UNLIKELY (i > 31))
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return FALSE;
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if (G_UNLIKELY (!nal_reader_get_bits_uint32 (nr, &value, i)))
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return FALSE;
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*val = (1 << i) - 1 + value;
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return TRUE;
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}
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gboolean
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nal_reader_get_se (NalReader * nr, gint32 * val)
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{
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guint32 value;
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if (G_UNLIKELY (!nal_reader_get_ue (nr, &value)))
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return FALSE;
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if (value % 2)
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*val = (value / 2) + 1;
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else
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*val = -(value / 2);
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return TRUE;
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}
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gboolean
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nal_reader_is_byte_aligned (NalReader * nr)
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{
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if (nr->bits_in_cache != 0)
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return FALSE;
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return TRUE;
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}
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gboolean
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nal_reader_has_more_data (NalReader * nr)
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{
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NalReader nr_tmp;
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guint remaining, nbits;
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guint8 rbsp_stop_one_bit, zero_bits;
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remaining = nal_reader_get_remaining (nr);
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if (remaining == 0)
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return FALSE;
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nr_tmp = *nr;
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nr = &nr_tmp;
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/* The spec defines that more_rbsp_data() searches for the last bit
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equal to 1, and that it is the rbsp_stop_one_bit. Subsequent bits
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until byte boundary is reached shall be zero.
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This means that more_rbsp_data() is FALSE if the next bit is 1
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and the remaining bits until byte boundary are zero. One way to
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be sure that this bit was the very last one, is that every other
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bit after we reached byte boundary are also set to zero.
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Otherwise, if the next bit is 0 or if there are non-zero bits
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afterwards, then then we have more_rbsp_data() */
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if (!nal_reader_get_bits_uint8 (nr, &rbsp_stop_one_bit, 1))
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return FALSE;
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if (!rbsp_stop_one_bit)
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return TRUE;
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nbits = --remaining % 8;
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while (remaining > 0) {
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if (!nal_reader_get_bits_uint8 (nr, &zero_bits, nbits))
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return FALSE;
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if (zero_bits != 0)
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return TRUE;
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remaining -= nbits;
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nbits = 8;
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}
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return FALSE;
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}
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/*********** end of nal parser ***************/
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gint
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scan_for_start_codes (const guint8 * data, guint size)
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{
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GstByteReader br;
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gst_byte_reader_init (&br, data, size);
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/* NALU not empty, so we can at least expect 1 (even 2) bytes following sc */
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return gst_byte_reader_masked_scan_uint32 (&br, 0xffffff00, 0x00000100,
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0, size);
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}
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void
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nal_writer_init (NalWriter * nw, guint nal_prefix_size, gboolean packetized)
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{
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g_return_if_fail (nw != NULL);
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g_return_if_fail ((packetized && nal_prefix_size > 1 && nal_prefix_size < 5)
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|| (!packetized && (nal_prefix_size == 3 || nal_prefix_size == 4)));
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gst_bit_writer_init (&nw->bw);
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nw->nal_prefix_size = nal_prefix_size;
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nw->packetized = packetized;
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}
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void
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nal_writer_reset (NalWriter * nw)
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{
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g_return_if_fail (nw != NULL);
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gst_bit_writer_reset (&nw->bw);
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memset (nw, 0, sizeof (NalWriter));
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}
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gboolean
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nal_writer_do_rbsp_trailing_bits (NalWriter * nw)
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{
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g_return_val_if_fail (nw != NULL, FALSE);
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if (!gst_bit_writer_put_bits_uint8 (&nw->bw, 1, 1)) {
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GST_WARNING ("Cannot put trailing bits");
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return FALSE;
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}
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if (!gst_bit_writer_align_bytes (&nw->bw, 0)) {
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GST_WARNING ("Cannot put align bits");
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return FALSE;
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}
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return TRUE;
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}
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static gpointer
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nal_writer_create_nal_data (NalWriter * nw, guint32 * ret_size)
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{
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GstBitWriter bw;
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gint i;
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guint8 *src, *dst;
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gsize size;
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gpointer data;
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/* scan to put emulation_prevention_three_byte */
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size = GST_BIT_WRITER_BIT_SIZE (&nw->bw) >> 3;
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src = GST_BIT_WRITER_DATA (&nw->bw);
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gst_bit_writer_init_with_size (&bw, size + nw->nal_prefix_size, FALSE);
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for (i = 0; i < nw->nal_prefix_size - 1; i++)
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gst_bit_writer_put_bits_uint8 (&bw, 0, 8);
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gst_bit_writer_put_bits_uint8 (&bw, 1, 8);
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for (i = 0; i < size; i++) {
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guint pos = (GST_BIT_WRITER_BIT_SIZE (&bw) >> 3);
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dst = GST_BIT_WRITER_DATA (&bw);
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if (pos >= nw->nal_prefix_size + 2 &&
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dst[pos - 2] == 0 && dst[pos - 1] == 0 && src[i] <= 0x3) {
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gst_bit_writer_put_bits_uint8 (&bw, 0x3, 8);
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}
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gst_bit_writer_put_bits_uint8 (&bw, src[i], 8);
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}
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*ret_size = bw.bit_size >> 3;
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data = gst_bit_writer_reset_and_get_data (&bw);
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if (nw->packetized) {
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size = *ret_size - nw->nal_prefix_size;
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switch (nw->nal_prefix_size) {
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case 1:
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GST_WRITE_UINT8 (data, size);
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break;
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case 2:
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GST_WRITE_UINT16_BE (data, size);
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break;
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case 3:
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GST_WRITE_UINT24_BE (data, size);
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break;
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case 4:
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GST_WRITE_UINT32_BE (data, size);
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break;
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default:
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g_assert_not_reached ();
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break;
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}
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}
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return data;
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}
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GstMemory *
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nal_writer_reset_and_get_memory (NalWriter * nw)
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{
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guint32 size = 0;
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GstMemory *ret = NULL;
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gpointer data;
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g_return_val_if_fail (nw != NULL, NULL);
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if ((GST_BIT_WRITER_BIT_SIZE (&nw->bw) >> 3) == 0) {
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GST_WARNING ("No written byte");
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goto done;
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}
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if ((GST_BIT_WRITER_BIT_SIZE (&nw->bw) & 0x7) != 0) {
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GST_WARNING ("Written stream is not byte aligned");
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if (!nal_writer_do_rbsp_trailing_bits (nw))
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goto done;
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}
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data = nal_writer_create_nal_data (nw, &size);
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if (!data) {
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GST_WARNING ("Failed to create nal data");
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goto done;
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}
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ret = gst_memory_new_wrapped (0, data, size, 0, size, data, g_free);
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done:
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gst_bit_writer_reset (&nw->bw);
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return ret;
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}
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guint8 *
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nal_writer_reset_and_get_data (NalWriter * nw, guint32 * ret_size)
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{
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guint32 size = 0;
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guint8 *data = NULL;
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g_return_val_if_fail (nw != NULL, NULL);
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g_return_val_if_fail (ret_size != NULL, NULL);
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*ret_size = 0;
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if ((GST_BIT_WRITER_BIT_SIZE (&nw->bw) >> 3) == 0) {
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GST_WARNING ("No written byte");
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goto done;
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}
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if ((GST_BIT_WRITER_BIT_SIZE (&nw->bw) & 0x7) != 0) {
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GST_WARNING ("Written stream is not byte aligned");
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if (!nal_writer_do_rbsp_trailing_bits (nw))
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goto done;
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}
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data = nal_writer_create_nal_data (nw, &size);
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if (!data) {
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GST_WARNING ("Failed to create nal data");
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goto done;
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}
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*ret_size = size;
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done:
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gst_bit_writer_reset (&nw->bw);
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return data;
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}
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gboolean
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nal_writer_put_bits_uint8 (NalWriter * nw, guint8 value, guint nbits)
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{
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g_return_val_if_fail (nw != NULL, FALSE);
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if (!gst_bit_writer_put_bits_uint8 (&nw->bw, value, nbits))
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return FALSE;
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return TRUE;
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}
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gboolean
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nal_writer_put_bits_uint16 (NalWriter * nw, guint16 value, guint nbits)
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{
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g_return_val_if_fail (nw != NULL, FALSE);
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if (!gst_bit_writer_put_bits_uint16 (&nw->bw, value, nbits))
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return FALSE;
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return TRUE;
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}
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gboolean
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nal_writer_put_bits_uint32 (NalWriter * nw, guint32 value, guint nbits)
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{
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g_return_val_if_fail (nw != NULL, FALSE);
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if (!gst_bit_writer_put_bits_uint32 (&nw->bw, value, nbits))
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return FALSE;
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return TRUE;
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}
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gboolean
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nal_writer_put_bytes (NalWriter * nw, const guint8 * data, guint nbytes)
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{
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g_return_val_if_fail (nw != NULL, FALSE);
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g_return_val_if_fail (data != NULL, FALSE);
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g_return_val_if_fail (nbytes != 0, FALSE);
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if (!gst_bit_writer_put_bytes (&nw->bw, data, nbytes))
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return FALSE;
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return TRUE;
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}
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gboolean
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nal_writer_put_ue (NalWriter * nw, guint32 value)
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{
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guint leading_zeros;
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guint rest;
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g_return_val_if_fail (nw != NULL, FALSE);
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count_exp_golomb_bits (value, &leading_zeros, &rest);
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/* write leading zeros */
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if (leading_zeros) {
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if (!nal_writer_put_bits_uint32 (nw, 0, leading_zeros))
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return FALSE;
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}
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/* write the rest */
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if (!nal_writer_put_bits_uint32 (nw, value + 1, rest))
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return FALSE;
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return TRUE;
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}
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gboolean
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count_exp_golomb_bits (guint32 value, guint * leading_zeros, guint * rest)
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{
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guint32 x;
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guint count = 0;
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/* https://en.wikipedia.org/wiki/Exponential-Golomb_coding */
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/* count bits of value + 1 */
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x = value + 1;
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while (x) {
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count++;
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x >>= 1;
|
|
}
|
|
|
|
if (leading_zeros) {
|
|
if (count > 1)
|
|
*leading_zeros = count - 1;
|
|
else
|
|
*leading_zeros = 0;
|
|
}
|
|
|
|
if (rest) {
|
|
*rest = count;
|
|
}
|
|
|
|
return TRUE;
|
|
}
|