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9ed6ac1f76
Implements gst_vaapi_utils_h26x_write_nal_unit(), which writes NAL unit length and data to a bitwriter. Note that this helper function applies EPB (Emulation Prevention Bytes), since otherwise produced codec_data might be broken when decoder/parser considering EPB, starts parsing. See sections 7.3 and 7.4 of the H264 and H264 specifications, which describes the emulation_prevention_three_byte. https://bugzilla.gnome.org/show_bug.cgi?id=778750 Signed-off-by: Víctor Manuel Jáquez Leal <victorx.jaquez@intel.com>
147 lines
3.7 KiB
C
147 lines
3.7 KiB
C
/*
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* gstvaapiutils_h26x.c - H.26x related utilities
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*
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* Copyright (C) 2011-2014 Intel Corporation
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* Author: Gwenole Beauchesne
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* Copyright (C) 2017 Intel Corporation
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* Author: Hyunjun Ko <zzoon@igalia.com>
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* Author: Mark Thompson <sw@jkqxz.net>
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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 Lesser General Public License
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* as published by the Free Software Foundation; either version 2.1
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* 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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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free
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* Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301 USA
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*/
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#include "gstvaapiutils_h26x_priv.h"
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/* Write an unsigned integer Exp-Golomb-coded syntax element. i.e. ue(v) */
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gboolean
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bs_write_ue (GstBitWriter * bs, guint32 value)
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{
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guint32 size_in_bits = 0;
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guint32 tmp_value = ++value;
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while (tmp_value) {
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++size_in_bits;
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tmp_value >>= 1;
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}
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if (size_in_bits > 1
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&& !gst_bit_writer_put_bits_uint32 (bs, 0, size_in_bits - 1))
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return FALSE;
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if (!gst_bit_writer_put_bits_uint32 (bs, value, size_in_bits))
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return FALSE;
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return TRUE;
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}
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/* Write a signed integer Exp-Golomb-coded syntax element. i.e. se(v) */
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gboolean
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bs_write_se (GstBitWriter * bs, gint32 value)
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{
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guint32 new_val;
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if (value <= 0)
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new_val = -(value << 1);
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else
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new_val = (value << 1) - 1;
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if (!bs_write_ue (bs, new_val))
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return FALSE;
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return TRUE;
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}
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/* Copy from src to dst, applying emulation prevention bytes.
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*
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* This is copied from libavcodec written by Mark Thompson
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* <sw@jkqxz.net> from
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* http://git.videolan.org/?p=ffmpeg.git;a=commit;h=2c62fcdf5d617791a653d7957d449f75569eede0
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*/
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static gboolean
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gst_vaapi_utils_h26x_nal_unit_to_byte_stream (guint8 * dst, guint * dst_len,
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guint8 * src, guint src_len)
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{
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guint dp = 0, sp;
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guint zero_run = 0;
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for (sp = 0; sp < src_len; sp++) {
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if (dp >= *dst_len)
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goto fail;
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if (zero_run < 2) {
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if (src[sp] == 0)
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++zero_run;
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else
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zero_run = 0;
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} else {
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if ((src[sp] & ~3) == 0) {
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/* emulation_prevention_byte: 0x03 */
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dst[dp++] = 3;
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if (dp >= *dst_len)
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goto fail;
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}
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zero_run = src[sp] == 0;
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}
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dst[dp++] = src[sp];
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}
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*dst_len = dp;
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return TRUE;
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fail:
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*dst_len = 0;
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return FALSE;
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}
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/**
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* gst_vaapi_utils_h26x_write_nal_unit:
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* @bs: a #GstBitWriter instance
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* @nal: the NAL (Network Abstraction Layer) unit to write
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* @nal_size: the size, in bytes, of @nal
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*
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* Writes in the @bs the @nal rewritten with the "emulation prevention
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* bytes" if required.
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*
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* Returns: TRUE if the NAL unit could be coded applying the
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* "emulation prevention bytes"; otherwise FALSE.
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**/
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gboolean
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gst_vaapi_utils_h26x_write_nal_unit (GstBitWriter * bs, guint8 * nal,
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guint nal_size)
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{
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guint8 *byte_stream = NULL;
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guint byte_stream_len;
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byte_stream_len = nal_size + 10;
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byte_stream = g_malloc (byte_stream_len);
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if (!byte_stream)
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return FALSE;
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if (!gst_vaapi_utils_h26x_nal_unit_to_byte_stream (byte_stream,
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&byte_stream_len, nal, nal_size)) {
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g_free (byte_stream);
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return FALSE;
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}
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WRITE_UINT32 (bs, byte_stream_len, 16);
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gst_bit_writer_put_bytes (bs, byte_stream, byte_stream_len);
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g_free (byte_stream);
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return TRUE;
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bs_error:
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{
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GST_ERROR ("failed to write codec-data");
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g_free (byte_stream);
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return FALSE;
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}
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}
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