260 lines
6.7 KiB
C
Executable file
260 lines
6.7 KiB
C
Executable file
/*
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* TW5864 driver - H.264 headers generation functions
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*
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* Copyright (C) 2016 Bluecherry, LLC <maintainers@bluecherrydvr.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*/
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#include <linux/log2.h>
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#include "tw5864.h"
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static u8 marker[] = { 0x00, 0x00, 0x00, 0x01 };
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/*
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* Exponential-Golomb coding functions
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*
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* These functions are used for generation of H.264 bitstream headers.
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*
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* This code is derived from tw5864 reference driver by manufacturers, which
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* itself apparently was derived from x264 project.
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*/
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/* Bitstream writing context */
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struct bs {
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u8 *buf; /* pointer to buffer beginning */
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u8 *buf_end; /* pointer to buffer end */
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u8 *ptr; /* pointer to current byte in buffer */
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unsigned int bits_left; /* number of available bits in current byte */
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};
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static void bs_init(struct bs *s, void *buf, int size)
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{
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s->buf = buf;
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s->ptr = buf;
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s->buf_end = s->ptr + size;
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s->bits_left = 8;
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}
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static int bs_len(struct bs *s)
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{
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return s->ptr - s->buf;
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}
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static void bs_write(struct bs *s, int count, u32 bits)
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{
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if (s->ptr >= s->buf_end - 4)
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return;
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while (count > 0) {
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if (count < 32)
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bits &= (1 << count) - 1;
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if (count < s->bits_left) {
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*s->ptr = (*s->ptr << count) | bits;
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s->bits_left -= count;
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break;
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}
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*s->ptr = (*s->ptr << s->bits_left) |
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(bits >> (count - s->bits_left));
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count -= s->bits_left;
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s->ptr++;
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s->bits_left = 8;
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}
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}
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static void bs_write1(struct bs *s, u32 bit)
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{
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if (s->ptr < s->buf_end) {
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*s->ptr <<= 1;
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*s->ptr |= bit;
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s->bits_left--;
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if (s->bits_left == 0) {
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s->ptr++;
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s->bits_left = 8;
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}
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}
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}
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static void bs_write_ue(struct bs *s, u32 val)
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{
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if (val == 0) {
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bs_write1(s, 1);
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} else {
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val++;
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bs_write(s, 2 * fls(val) - 1, val);
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}
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}
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static void bs_write_se(struct bs *s, int val)
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{
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bs_write_ue(s, val <= 0 ? -val * 2 : val * 2 - 1);
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}
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static void bs_rbsp_trailing(struct bs *s)
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{
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bs_write1(s, 1);
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if (s->bits_left != 8)
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bs_write(s, s->bits_left, 0x00);
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}
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/* H.264 headers generation functions */
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static int tw5864_h264_gen_sps_rbsp(u8 *buf, size_t size, int width, int height)
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{
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struct bs bs, *s;
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s = &bs;
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bs_init(s, buf, size);
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bs_write(s, 8, 0x42); /* profile_idc, baseline */
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bs_write(s, 1, 1); /* constraint_set0_flag */
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bs_write(s, 1, 1); /* constraint_set1_flag */
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bs_write(s, 1, 0); /* constraint_set2_flag */
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bs_write(s, 5, 0); /* reserved_zero_5bits */
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bs_write(s, 8, 0x1e); /* level_idc */
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bs_write_ue(s, 0); /* seq_parameter_set_id */
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bs_write_ue(s, ilog2(MAX_GOP_SIZE) - 4); /* log2_max_frame_num_minus4 */
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bs_write_ue(s, 0); /* pic_order_cnt_type */
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/* log2_max_pic_order_cnt_lsb_minus4 */
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bs_write_ue(s, ilog2(MAX_GOP_SIZE) - 4);
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bs_write_ue(s, 1); /* num_ref_frames */
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bs_write(s, 1, 0); /* gaps_in_frame_num_value_allowed_flag */
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bs_write_ue(s, width / 16 - 1); /* pic_width_in_mbs_minus1 */
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bs_write_ue(s, height / 16 - 1); /* pic_height_in_map_units_minus1 */
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bs_write(s, 1, 1); /* frame_mbs_only_flag */
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bs_write(s, 1, 0); /* direct_8x8_inference_flag */
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bs_write(s, 1, 0); /* frame_cropping_flag */
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bs_write(s, 1, 0); /* vui_parameters_present_flag */
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bs_rbsp_trailing(s);
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return bs_len(s);
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}
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static int tw5864_h264_gen_pps_rbsp(u8 *buf, size_t size, int qp)
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{
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struct bs bs, *s;
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s = &bs;
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bs_init(s, buf, size);
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bs_write_ue(s, 0); /* pic_parameter_set_id */
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bs_write_ue(s, 0); /* seq_parameter_set_id */
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bs_write(s, 1, 0); /* entropy_coding_mode_flag */
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bs_write(s, 1, 0); /* pic_order_present_flag */
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bs_write_ue(s, 0); /* num_slice_groups_minus1 */
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bs_write_ue(s, 0); /* i_num_ref_idx_l0_active_minus1 */
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bs_write_ue(s, 0); /* i_num_ref_idx_l1_active_minus1 */
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bs_write(s, 1, 0); /* weighted_pred_flag */
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bs_write(s, 2, 0); /* weighted_bipred_idc */
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bs_write_se(s, qp - 26); /* pic_init_qp_minus26 */
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bs_write_se(s, qp - 26); /* pic_init_qs_minus26 */
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bs_write_se(s, 0); /* chroma_qp_index_offset */
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bs_write(s, 1, 0); /* deblocking_filter_control_present_flag */
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bs_write(s, 1, 0); /* constrained_intra_pred_flag */
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bs_write(s, 1, 0); /* redundant_pic_cnt_present_flag */
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bs_rbsp_trailing(s);
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return bs_len(s);
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}
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static int tw5864_h264_gen_slice_head(u8 *buf, size_t size,
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unsigned int idr_pic_id,
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unsigned int frame_gop_seqno,
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int *tail_nb_bits, u8 *tail)
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{
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struct bs bs, *s;
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int is_i_frame = frame_gop_seqno == 0;
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s = &bs;
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bs_init(s, buf, size);
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bs_write_ue(s, 0); /* first_mb_in_slice */
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bs_write_ue(s, is_i_frame ? 2 : 5); /* slice_type - I or P */
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bs_write_ue(s, 0); /* pic_parameter_set_id */
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bs_write(s, ilog2(MAX_GOP_SIZE), frame_gop_seqno); /* frame_num */
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if (is_i_frame)
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bs_write_ue(s, idr_pic_id);
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/* pic_order_cnt_lsb */
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bs_write(s, ilog2(MAX_GOP_SIZE), frame_gop_seqno);
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if (is_i_frame) {
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bs_write1(s, 0); /* no_output_of_prior_pics_flag */
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bs_write1(s, 0); /* long_term_reference_flag */
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} else {
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bs_write1(s, 0); /* num_ref_idx_active_override_flag */
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bs_write1(s, 0); /* ref_pic_list_reordering_flag_l0 */
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bs_write1(s, 0); /* adaptive_ref_pic_marking_mode_flag */
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}
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bs_write_se(s, 0); /* slice_qp_delta */
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if (s->bits_left != 8) {
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*tail = ((s->ptr[0]) << s->bits_left);
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*tail_nb_bits = 8 - s->bits_left;
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} else {
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*tail = 0;
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*tail_nb_bits = 0;
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}
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return bs_len(s);
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}
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void tw5864_h264_put_stream_header(u8 **buf, size_t *space_left, int qp,
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int width, int height)
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{
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int nal_len;
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/* SPS */
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memcpy(*buf, marker, sizeof(marker));
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*buf += 4;
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*space_left -= 4;
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**buf = 0x67; /* SPS NAL header */
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*buf += 1;
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*space_left -= 1;
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nal_len = tw5864_h264_gen_sps_rbsp(*buf, *space_left, width, height);
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*buf += nal_len;
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*space_left -= nal_len;
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/* PPS */
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memcpy(*buf, marker, sizeof(marker));
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*buf += 4;
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*space_left -= 4;
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**buf = 0x68; /* PPS NAL header */
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*buf += 1;
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*space_left -= 1;
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nal_len = tw5864_h264_gen_pps_rbsp(*buf, *space_left, qp);
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*buf += nal_len;
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*space_left -= nal_len;
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}
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void tw5864_h264_put_slice_header(u8 **buf, size_t *space_left,
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unsigned int idr_pic_id,
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unsigned int frame_gop_seqno,
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int *tail_nb_bits, u8 *tail)
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{
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int nal_len;
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memcpy(*buf, marker, sizeof(marker));
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*buf += 4;
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*space_left -= 4;
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/* Frame NAL header */
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**buf = (frame_gop_seqno == 0) ? 0x25 : 0x21;
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*buf += 1;
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*space_left -= 1;
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nal_len = tw5864_h264_gen_slice_head(*buf, *space_left, idr_pic_id,
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frame_gop_seqno, tail_nb_bits,
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tail);
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*buf += nal_len;
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*space_left -= nal_len;
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}
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