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1/* SPDX-License-Identifier: GPL-2.0 */2/*3 * Vidtv serves as a reference DVB driver and helps validate the existing APIs4 * in the media subsystem. It can also aid developers working on userspace5 * applications.6 *7 * This file contains the logic to translate the ES data for one access unit8 * from an encoder into MPEG TS packets. It does so by first encapsulating it9 * with a PES header and then splitting it into TS packets.10 *11 * Copyright (C) 2020 Daniel W. S. Almeida12 */13 14#ifndef VIDTV_PES_H15#define VIDTV_PES_H16 17#include <linux/types.h>18 19#include "vidtv_common.h"20 21#define PES_MAX_LEN 65536 /* Set 'length' to 0 if greater. Only possible for video. */22#define PES_START_CODE_PREFIX 0x001 /* 00 00 01 */23 24/* Used when sending PTS, but not DTS */25struct vidtv_pes_optional_pts {26 u8 pts1;27 __be16 pts2;28 __be16 pts3;29} __packed;30 31/* Used when sending both PTS and DTS */32struct vidtv_pes_optional_pts_dts {33 u8 pts1;34 __be16 pts2;35 __be16 pts3;36 37 u8 dts1;38 __be16 dts2;39 __be16 dts3;40} __packed;41 42/* PES optional flags */43struct vidtv_pes_optional {44 /*45 * These flags show which components are actually46 * present in the "optional fields" in the optional PES47 * header and which are not48 *49 * u16 two:2; //0x250 * u16 PES_scrambling_control:2;51 * u16 PES_priority:1;52 * u16 data_alignment_indicator:1; // unused53 * u16 copyright:1;54 * u16 original_or_copy:1;55 * u16 PTS_DTS:2;56 * u16 ESCR:1;57 * u16 ES_rate:1;58 * u16 DSM_trick_mode:1;59 * u16 additional_copy_info:1;60 * u16 PES_CRC:1;61 * u16 PES_extension:1;62 */63 __be16 bitfield;64 u8 length;65} __packed;66 67/* The PES header */68struct vidtv_mpeg_pes {69 __be32 bitfield; /* packet_start_code_prefix:24, stream_id: 8 */70 /* after this field until the end of the PES data payload */71 __be16 length;72 struct vidtv_pes_optional optional[];73} __packed;74 75/**76 * struct pes_header_write_args - Arguments to write a PES header.77 * @dest_buf: The buffer to write into.78 * @dest_offset: where to start writing in the dest_buffer.79 * @dest_buf_sz: The size of the dest_buffer80 * @encoder_id: Encoder id (see vidtv_encoder.h)81 * @send_pts: Should we send PTS?82 * @pts: PTS value to send.83 * @send_dts: Should we send DTS?84 * @dts: DTS value to send.85 * @stream_id: The stream id to use. Ex: Audio streams (0xc0-0xdf), Video86 * streams (0xe0-0xef).87 * @n_pes_h_s_bytes: Padding bytes. Might be used by an encoder if needed, gets88 * discarded by the decoder.89 * @access_unit_len: The size of _one_ access unit (with any headers it might need)90 */91struct pes_header_write_args {92 void *dest_buf;93 u32 dest_offset;94 u32 dest_buf_sz;95 u32 encoder_id;96 97 bool send_pts;98 u64 pts;99 100 bool send_dts;101 u64 dts;102 103 u16 stream_id;104 /* might be used by an encoder if needed, gets discarded by decoder */105 u32 n_pes_h_s_bytes;106 u32 access_unit_len;107};108 109/**110 * struct pes_ts_header_write_args - Arguments to write a TS header.111 * @dest_buf: The buffer to write into.112 * @dest_offset: where to start writing in the dest_buffer.113 * @dest_buf_sz: The size of the dest_buffer114 * @pid: The PID to use for the TS packets.115 * @continuity_counter: Incremented on every new TS packet.116 * @wrote_pes_header: Flag to indicate that the PES header was written117 * @n_stuffing_bytes: Padding bytes. Might be used by an encoder if needed, gets118 * discarded by the decoder.119 * @pcr: counter driven by a 27Mhz clock.120 */121struct pes_ts_header_write_args {122 void *dest_buf;123 u32 dest_offset;124 u32 dest_buf_sz;125 u16 pid;126 u8 *continuity_counter;127 bool wrote_pes_header;128 u32 n_stuffing_bytes;129 u64 pcr;130};131 132/**133 * struct pes_write_args - Arguments for the packetizer.134 * @dest_buf: The buffer to write into.135 * @from: A pointer to the encoder buffer containing one access unit.136 * @access_unit_len: The size of _one_ access unit (with any headers it might need)137 * @dest_offset: where to start writing in the dest_buffer.138 * @dest_buf_sz: The size of the dest_buffer139 * @pid: The PID to use for the TS packets.140 * @encoder_id: Encoder id (see vidtv_encoder.h)141 * @continuity_counter: Incremented on every new TS packet.142 * @stream_id: The stream id to use. Ex: Audio streams (0xc0-0xdf), Video143 * streams (0xe0-0xef).144 * @send_pts: Should we send PTS?145 * @pts: PTS value to send.146 * @send_dts: Should we send DTS?147 * @dts: DTS value to send.148 * @n_pes_h_s_bytes: Padding bytes. Might be used by an encoder if needed, gets149 * discarded by the decoder.150 * @pcr: counter driven by a 27Mhz clock.151 */152struct pes_write_args {153 void *dest_buf;154 void *from;155 u32 access_unit_len;156 157 u32 dest_offset;158 u32 dest_buf_sz;159 u16 pid;160 161 u32 encoder_id;162 163 u8 *continuity_counter;164 165 u16 stream_id;166 167 bool send_pts;168 u64 pts;169 170 bool send_dts;171 u64 dts;172 173 u32 n_pes_h_s_bytes;174 u64 pcr;175};176 177/**178 * vidtv_pes_write_into - Write a PES packet as MPEG-TS packets into a buffer.179 * @args: The args to use when writing180 *181 * This function translate the ES data for one access unit182 * from an encoder into MPEG TS packets. It does so by first encapsulating it183 * with a PES header and then splitting it into TS packets.184 *185 * The data is then written into the buffer pointed to by 'args.buf'186 *187 * Return: The number of bytes written into the buffer. This is usually NOT188 * equal to the size of the access unit, since we need space for PES headers, TS headers189 * and padding bytes, if any.190 */191u32 vidtv_pes_write_into(struct pes_write_args *args);192 193#endif // VIDTV_PES_H194