diff options
Diffstat (limited to 'drivers/media/test-drivers/vidtv/vidtv_pes.h')
| -rw-r--r-- | drivers/media/test-drivers/vidtv/vidtv_pes.h | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/drivers/media/test-drivers/vidtv/vidtv_pes.h b/drivers/media/test-drivers/vidtv/vidtv_pes.h new file mode 100644 index 000000000..963c59155 --- /dev/null +++ b/drivers/media/test-drivers/vidtv/vidtv_pes.h @@ -0,0 +1,193 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Vidtv serves as a reference DVB driver and helps validate the existing APIs + * in the media subsystem. It can also aid developers working on userspace + * applications. + * + * This file contains the logic to translate the ES data for one access unit + * from an encoder into MPEG TS packets. It does so by first encapsulating it + * with a PES header and then splitting it into TS packets. + * + * Copyright (C) 2020 Daniel W. S. Almeida + */ + +#ifndef VIDTV_PES_H +#define VIDTV_PES_H + +#include <linux/types.h> + +#include "vidtv_common.h" + +#define PES_MAX_LEN 65536 /* Set 'length' to 0 if greater. Only possible for video. */ +#define PES_START_CODE_PREFIX 0x001 /* 00 00 01 */ + +/* Used when sending PTS, but not DTS */ +struct vidtv_pes_optional_pts { + u8 pts1; + __be16 pts2; + __be16 pts3; +} __packed; + +/* Used when sending both PTS and DTS */ +struct vidtv_pes_optional_pts_dts { + u8 pts1; + __be16 pts2; + __be16 pts3; + + u8 dts1; + __be16 dts2; + __be16 dts3; +} __packed; + +/* PES optional flags */ +struct vidtv_pes_optional { + /* + * These flags show which components are actually + * present in the "optional fields" in the optional PES + * header and which are not + * + * u16 two:2; //0x2 + * u16 PES_scrambling_control:2; + * u16 PES_priority:1; + * u16 data_alignment_indicator:1; // unused + * u16 copyright:1; + * u16 original_or_copy:1; + * u16 PTS_DTS:2; + * u16 ESCR:1; + * u16 ES_rate:1; + * u16 DSM_trick_mode:1; + * u16 additional_copy_info:1; + * u16 PES_CRC:1; + * u16 PES_extension:1; + */ + __be16 bitfield; + u8 length; +} __packed; + +/* The PES header */ +struct vidtv_mpeg_pes { + __be32 bitfield; /* packet_start_code_prefix:24, stream_id: 8 */ + /* after this field until the end of the PES data payload */ + __be16 length; + struct vidtv_pes_optional optional[]; +} __packed; + +/** + * struct pes_header_write_args - Arguments to write a PES header. + * @dest_buf: The buffer to write into. + * @dest_offset: where to start writing in the dest_buffer. + * @dest_buf_sz: The size of the dest_buffer + * @encoder_id: Encoder id (see vidtv_encoder.h) + * @send_pts: Should we send PTS? + * @pts: PTS value to send. + * @send_dts: Should we send DTS? + * @dts: DTS value to send. + * @stream_id: The stream id to use. Ex: Audio streams (0xc0-0xdf), Video + * streams (0xe0-0xef). + * @n_pes_h_s_bytes: Padding bytes. Might be used by an encoder if needed, gets + * discarded by the decoder. + * @access_unit_len: The size of _one_ access unit (with any headers it might need) + */ +struct pes_header_write_args { + void *dest_buf; + u32 dest_offset; + u32 dest_buf_sz; + u32 encoder_id; + + bool send_pts; + u64 pts; + + bool send_dts; + u64 dts; + + u16 stream_id; + /* might be used by an encoder if needed, gets discarded by decoder */ + u32 n_pes_h_s_bytes; + u32 access_unit_len; +}; + +/** + * struct pes_ts_header_write_args - Arguments to write a TS header. + * @dest_buf: The buffer to write into. + * @dest_offset: where to start writing in the dest_buffer. + * @dest_buf_sz: The size of the dest_buffer + * @pid: The PID to use for the TS packets. + * @continuity_counter: Incremented on every new TS packet. + * @wrote_pes_header: Flag to indicate that the PES header was written + * @n_stuffing_bytes: Padding bytes. Might be used by an encoder if needed, gets + * discarded by the decoder. + * @pcr: counter driven by a 27Mhz clock. + */ +struct pes_ts_header_write_args { + void *dest_buf; + u32 dest_offset; + u32 dest_buf_sz; + u16 pid; + u8 *continuity_counter; + bool wrote_pes_header; + u32 n_stuffing_bytes; + u64 pcr; +}; + +/** + * struct pes_write_args - Arguments for the packetizer. + * @dest_buf: The buffer to write into. + * @from: A pointer to the encoder buffer containing one access unit. + * @access_unit_len: The size of _one_ access unit (with any headers it might need) + * @dest_offset: where to start writing in the dest_buffer. + * @dest_buf_sz: The size of the dest_buffer + * @pid: The PID to use for the TS packets. + * @encoder_id: Encoder id (see vidtv_encoder.h) + * @continuity_counter: Incremented on every new TS packet. + * @stream_id: The stream id to use. Ex: Audio streams (0xc0-0xdf), Video + * streams (0xe0-0xef). + * @send_pts: Should we send PTS? + * @pts: PTS value to send. + * @send_dts: Should we send DTS? + * @dts: DTS value to send. + * @n_pes_h_s_bytes: Padding bytes. Might be used by an encoder if needed, gets + * discarded by the decoder. + * @pcr: counter driven by a 27Mhz clock. + */ +struct pes_write_args { + void *dest_buf; + void *from; + u32 access_unit_len; + + u32 dest_offset; + u32 dest_buf_sz; + u16 pid; + + u32 encoder_id; + + u8 *continuity_counter; + + u16 stream_id; + + bool send_pts; + u64 pts; + + bool send_dts; + u64 dts; + + u32 n_pes_h_s_bytes; + u64 pcr; +}; + +/** + * vidtv_pes_write_into - Write a PES packet as MPEG-TS packets into a buffer. + * @args: The args to use when writing + * + * This function translate the ES data for one access unit + * from an encoder into MPEG TS packets. It does so by first encapsulating it + * with a PES header and then splitting it into TS packets. + * + * The data is then written into the buffer pointed to by 'args.buf' + * + * Return: The number of bytes written into the buffer. This is usually NOT + * equal to the size of the access unit, since we need space for PES headers, TS headers + * and padding bytes, if any. + */ +u32 vidtv_pes_write_into(struct pes_write_args *args); + +#endif // VIDTV_PES_H |