diff options
Diffstat (limited to 'drivers/media/pci/tw5864/tw5864-h264.c')
| -rw-r--r-- | drivers/media/pci/tw5864/tw5864-h264.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/drivers/media/pci/tw5864/tw5864-h264.c b/drivers/media/pci/tw5864/tw5864-h264.c new file mode 100644 index 000000000..608798af6 --- /dev/null +++ b/drivers/media/pci/tw5864/tw5864-h264.c @@ -0,0 +1,250 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * TW5864 driver - H.264 headers generation functions + * + * Copyright (C) 2016 Bluecherry, LLC <maintainers@bluecherrydvr.com> + */ + +#include <linux/log2.h> + +#include "tw5864.h" + +static u8 marker[] = { 0x00, 0x00, 0x00, 0x01 }; + +/* + * Exponential-Golomb coding functions + * + * These functions are used for generation of H.264 bitstream headers. + * + * This code is derived from tw5864 reference driver by manufacturers, which + * itself apparently was derived from x264 project. + */ + +/* Bitstream writing context */ +struct bs { + u8 *buf; /* pointer to buffer beginning */ + u8 *buf_end; /* pointer to buffer end */ + u8 *ptr; /* pointer to current byte in buffer */ + unsigned int bits_left; /* number of available bits in current byte */ +}; + +static void bs_init(struct bs *s, void *buf, int size) +{ + s->buf = buf; + s->ptr = buf; + s->buf_end = s->ptr + size; + s->bits_left = 8; +} + +static int bs_len(struct bs *s) +{ + return s->ptr - s->buf; +} + +static void bs_write(struct bs *s, int count, u32 bits) +{ + if (s->ptr >= s->buf_end - 4) + return; + while (count > 0) { + if (count < 32) + bits &= (1 << count) - 1; + if (count < s->bits_left) { + *s->ptr = (*s->ptr << count) | bits; + s->bits_left -= count; + break; + } + *s->ptr = (*s->ptr << s->bits_left) | + (bits >> (count - s->bits_left)); + count -= s->bits_left; + s->ptr++; + s->bits_left = 8; + } +} + +static void bs_write1(struct bs *s, u32 bit) +{ + if (s->ptr < s->buf_end) { + *s->ptr <<= 1; + *s->ptr |= bit; + s->bits_left--; + if (s->bits_left == 0) { + s->ptr++; + s->bits_left = 8; + } + } +} + +static void bs_write_ue(struct bs *s, u32 val) +{ + if (val == 0) { + bs_write1(s, 1); + } else { + val++; + bs_write(s, 2 * fls(val) - 1, val); + } +} + +static void bs_write_se(struct bs *s, int val) +{ + bs_write_ue(s, val <= 0 ? -val * 2 : val * 2 - 1); +} + +static void bs_rbsp_trailing(struct bs *s) +{ + bs_write1(s, 1); + if (s->bits_left != 8) + bs_write(s, s->bits_left, 0x00); +} + +/* H.264 headers generation functions */ + +static int tw5864_h264_gen_sps_rbsp(u8 *buf, size_t size, int width, int height) +{ + struct bs bs, *s; + + s = &bs; + bs_init(s, buf, size); + bs_write(s, 8, 0x42); /* profile_idc, baseline */ + bs_write(s, 1, 1); /* constraint_set0_flag */ + bs_write(s, 1, 1); /* constraint_set1_flag */ + bs_write(s, 1, 0); /* constraint_set2_flag */ + bs_write(s, 5, 0); /* reserved_zero_5bits */ + bs_write(s, 8, 0x1e); /* level_idc */ + bs_write_ue(s, 0); /* seq_parameter_set_id */ + bs_write_ue(s, ilog2(MAX_GOP_SIZE) - 4); /* log2_max_frame_num_minus4 */ + bs_write_ue(s, 0); /* pic_order_cnt_type */ + /* log2_max_pic_order_cnt_lsb_minus4 */ + bs_write_ue(s, ilog2(MAX_GOP_SIZE) - 4); + bs_write_ue(s, 1); /* num_ref_frames */ + bs_write(s, 1, 0); /* gaps_in_frame_num_value_allowed_flag */ + bs_write_ue(s, width / 16 - 1); /* pic_width_in_mbs_minus1 */ + bs_write_ue(s, height / 16 - 1); /* pic_height_in_map_units_minus1 */ + bs_write(s, 1, 1); /* frame_mbs_only_flag */ + bs_write(s, 1, 0); /* direct_8x8_inference_flag */ + bs_write(s, 1, 0); /* frame_cropping_flag */ + bs_write(s, 1, 0); /* vui_parameters_present_flag */ + bs_rbsp_trailing(s); + return bs_len(s); +} + +static int tw5864_h264_gen_pps_rbsp(u8 *buf, size_t size, int qp) +{ + struct bs bs, *s; + + s = &bs; + bs_init(s, buf, size); + bs_write_ue(s, 0); /* pic_parameter_set_id */ + bs_write_ue(s, 0); /* seq_parameter_set_id */ + bs_write(s, 1, 0); /* entropy_coding_mode_flag */ + bs_write(s, 1, 0); /* pic_order_present_flag */ + bs_write_ue(s, 0); /* num_slice_groups_minus1 */ + bs_write_ue(s, 0); /* i_num_ref_idx_l0_active_minus1 */ + bs_write_ue(s, 0); /* i_num_ref_idx_l1_active_minus1 */ + bs_write(s, 1, 0); /* weighted_pred_flag */ + bs_write(s, 2, 0); /* weighted_bipred_idc */ + bs_write_se(s, qp - 26); /* pic_init_qp_minus26 */ + bs_write_se(s, qp - 26); /* pic_init_qs_minus26 */ + bs_write_se(s, 0); /* chroma_qp_index_offset */ + bs_write(s, 1, 0); /* deblocking_filter_control_present_flag */ + bs_write(s, 1, 0); /* constrained_intra_pred_flag */ + bs_write(s, 1, 0); /* redundant_pic_cnt_present_flag */ + bs_rbsp_trailing(s); + return bs_len(s); +} + +static int tw5864_h264_gen_slice_head(u8 *buf, size_t size, + unsigned int idr_pic_id, + unsigned int frame_gop_seqno, + int *tail_nb_bits, u8 *tail) +{ + struct bs bs, *s; + int is_i_frame = frame_gop_seqno == 0; + + s = &bs; + bs_init(s, buf, size); + bs_write_ue(s, 0); /* first_mb_in_slice */ + bs_write_ue(s, is_i_frame ? 2 : 5); /* slice_type - I or P */ + bs_write_ue(s, 0); /* pic_parameter_set_id */ + bs_write(s, ilog2(MAX_GOP_SIZE), frame_gop_seqno); /* frame_num */ + if (is_i_frame) + bs_write_ue(s, idr_pic_id); + + /* pic_order_cnt_lsb */ + bs_write(s, ilog2(MAX_GOP_SIZE), frame_gop_seqno); + + if (is_i_frame) { + bs_write1(s, 0); /* no_output_of_prior_pics_flag */ + bs_write1(s, 0); /* long_term_reference_flag */ + } else { + bs_write1(s, 0); /* num_ref_idx_active_override_flag */ + bs_write1(s, 0); /* ref_pic_list_reordering_flag_l0 */ + bs_write1(s, 0); /* adaptive_ref_pic_marking_mode_flag */ + } + + bs_write_se(s, 0); /* slice_qp_delta */ + + if (s->bits_left != 8) { + *tail = ((s->ptr[0]) << s->bits_left); + *tail_nb_bits = 8 - s->bits_left; + } else { + *tail = 0; + *tail_nb_bits = 0; + } + + return bs_len(s); +} + +void tw5864_h264_put_stream_header(u8 **buf, size_t *space_left, int qp, + int width, int height) +{ + int nal_len; + + /* SPS */ + memcpy(*buf, marker, sizeof(marker)); + *buf += 4; + *space_left -= 4; + + **buf = 0x67; /* SPS NAL header */ + *buf += 1; + *space_left -= 1; + + nal_len = tw5864_h264_gen_sps_rbsp(*buf, *space_left, width, height); + *buf += nal_len; + *space_left -= nal_len; + + /* PPS */ + memcpy(*buf, marker, sizeof(marker)); + *buf += 4; + *space_left -= 4; + + **buf = 0x68; /* PPS NAL header */ + *buf += 1; + *space_left -= 1; + + nal_len = tw5864_h264_gen_pps_rbsp(*buf, *space_left, qp); + *buf += nal_len; + *space_left -= nal_len; +} + +void tw5864_h264_put_slice_header(u8 **buf, size_t *space_left, + unsigned int idr_pic_id, + unsigned int frame_gop_seqno, + int *tail_nb_bits, u8 *tail) +{ + int nal_len; + + memcpy(*buf, marker, sizeof(marker)); + *buf += 4; + *space_left -= 4; + + /* Frame NAL header */ + **buf = (frame_gop_seqno == 0) ? 0x25 : 0x21; + *buf += 1; + *space_left -= 1; + + nal_len = tw5864_h264_gen_slice_head(*buf, *space_left, idr_pic_id, + frame_gop_seqno, tail_nb_bits, + tail); + *buf += nal_len; + *space_left -= nal_len; +} |