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FFmpeg/libavcodec/smpte_436m.h
2025-08-08 03:04:42 -07:00

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/*
* MXF SMPTE-436M VBI/ANC parsing functions
* Copyright (c) 2025 Jacob Lifshay
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVCODEC_SMPTE_436M_H
#define AVCODEC_SMPTE_436M_H
#include <stdint.h>
/**
* Iterator over the ANC packets in a single AV_CODEC_ID_SMPTE_436M_ANC AVPacket's data
*/
typedef struct AVSmpte436mAncIterator {
uint16_t anc_packets_left;
int size_left;
const uint8_t *data_left;
} AVSmpte436mAncIterator;
/**
* Wrapping Type from Table 7 (page 13) of:
* https://pub.smpte.org/latest/st436/s436m-2006.pdf
*/
typedef enum AVSmpte436mWrappingType
{
AV_SMPTE_436M_WRAPPING_TYPE_VANC_FRAME = 1,
AV_SMPTE_436M_WRAPPING_TYPE_VANC_FIELD_1 = 2,
AV_SMPTE_436M_WRAPPING_TYPE_VANC_FIELD_2 = 3,
AV_SMPTE_436M_WRAPPING_TYPE_VANC_PROGRESSIVE_FRAME = 4,
AV_SMPTE_436M_WRAPPING_TYPE_HANC_FRAME = 0x11,
AV_SMPTE_436M_WRAPPING_TYPE_HANC_FIELD_1 = 0x12,
AV_SMPTE_436M_WRAPPING_TYPE_HANC_FIELD_2 = 0x13,
AV_SMPTE_436M_WRAPPING_TYPE_HANC_PROGRESSIVE_FRAME = 0x14,
/** not a real wrapping type, just here to guarantee the enum is big enough */
AV_SMPTE_436M_WRAPPING_TYPE_MAX = 0xFF,
} AVSmpte436mWrappingType;
/**
* Payload Sample Coding from Table 4 (page 10) and Table 7 (page 13) of:
* https://pub.smpte.org/latest/st436/s436m-2006.pdf
*/
typedef enum AVSmpte436mPayloadSampleCoding
{
/** only used for VBI */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_1BIT_LUMA = 1,
/** only used for VBI */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_1BIT_COLOR_DIFF = 2,
/** only used for VBI */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_1BIT_LUMA_AND_COLOR_DIFF = 3,
/** used for VBI and ANC */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_8BIT_LUMA = 4,
/** used for VBI and ANC */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_8BIT_COLOR_DIFF = 5,
/** used for VBI and ANC */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_8BIT_LUMA_AND_COLOR_DIFF = 6,
/** used for VBI and ANC */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_10BIT_LUMA = 7,
/** used for VBI and ANC */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_10BIT_COLOR_DIFF = 8,
/** used for VBI and ANC */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_10BIT_LUMA_AND_COLOR_DIFF = 9,
/** only used for ANC */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_8BIT_LUMA_WITH_PARITY_ERROR = 10,
/** only used for ANC */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_8BIT_COLOR_DIFF_WITH_PARITY_ERROR = 11,
/** only used for ANC */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_8BIT_LUMA_AND_COLOR_DIFF_WITH_PARITY_ERROR = 12,
/** not a real sample coding, just here to guarantee the enum is big enough */
AV_SMPTE_436M_PAYLOAD_SAMPLE_CODING_MAX = 0xFF,
} AVSmpte436mPayloadSampleCoding;
/** the payload capacity of AVSmpte291mAnc8bit (and of AVSmpte291mAnc10bit when that gets added) */
#define AV_SMPTE_291M_ANC_PAYLOAD_CAPACITY 0xFF
/**
* An ANC packet with an 8-bit payload.
* This can be decoded from AVSmpte436mCodedAnc::payload.
*
* Note: Some ANC packets need a 10-bit payload, if stored in this struct,
* the most-significant 2 bits of each sample are discarded.
*/
typedef struct AVSmpte291mAnc8bit {
uint8_t did;
uint8_t sdid_or_dbn;
uint8_t data_count;
uint8_t payload[AV_SMPTE_291M_ANC_PAYLOAD_CAPACITY];
uint8_t checksum;
} AVSmpte291mAnc8bit;
/** max number of samples that can be stored in the payload of AVSmpte436mCodedAnc */
#define AV_SMPTE_436M_CODED_ANC_SAMPLE_CAPACITY \
(AV_SMPTE_291M_ANC_PAYLOAD_CAPACITY + 4) /* 4 for did, sdid_or_dbn, data_count, and checksum */
/** max number of bytes that can be stored in the payload of AVSmpte436mCodedAnc */
#define AV_SMPTE_436M_CODED_ANC_PAYLOAD_CAPACITY (((AV_SMPTE_436M_CODED_ANC_SAMPLE_CAPACITY + 2) / 3) * 4)
/**
* An encoded ANC packet within a single AV_CODEC_ID_SMPTE_436M_ANC AVPacket's data.
* The repeated section of Table 7 (page 13) of:
* https://pub.smpte.org/latest/st436/s436m-2006.pdf
*/
typedef struct AVSmpte436mCodedAnc {
uint16_t line_number;
AVSmpte436mWrappingType wrapping_type;
AVSmpte436mPayloadSampleCoding payload_sample_coding;
uint16_t payload_sample_count;
uint32_t payload_array_length;
/** the payload, has size payload_array_length.
* can be decoded into AVSmpte291mAnc8bit
*/
uint8_t payload[AV_SMPTE_436M_CODED_ANC_PAYLOAD_CAPACITY];
} AVSmpte436mCodedAnc;
/**
* Validate a AVSmpte436mCodedAnc structure. Doesn't check if the payload is valid.
* @param[in] anc ANC packet to validate
* @return 0 on success, AVERROR codes otherwise.
*/
int av_smpte_436m_coded_anc_validate(const AVSmpte436mCodedAnc *anc);
/**
* Encode ANC packets into a single AV_CODEC_ID_SMPTE_436M_ANC AVPacket's data.
* @param[in] anc_packet_count number of ANC packets to encode
* @param[in] anc_packets the ANC packets to encode
* @param[in] size the size of out. ignored if out is NULL.
* @param[out] out Output bytes. Doesn't write anything if out is NULL.
* @return the number of bytes written on success, AVERROR codes otherwise.
* If out is NULL, returns the number of bytes it would have written.
*/
int av_smpte_436m_anc_encode(uint8_t *out, int size, int anc_packet_count, const AVSmpte436mCodedAnc *anc_packets);
struct AVPacket;
/**
* Append more ANC packets to a single AV_CODEC_ID_SMPTE_436M_ANC AVPacket's data.
* @param[in] anc_packet_count number of ANC packets to encode
* @param[in] anc_packets the ANC packets to encode
* @param pkt the AVPacket to append to.
* it must either be size 0 or contain valid SMPTE_436M_ANC data.
* @return 0 on success, AVERROR codes otherwise.
*/
int av_smpte_436m_anc_append(struct AVPacket *pkt, int anc_packet_count, const AVSmpte436mCodedAnc *anc_packets);
/**
* Set up iteration over the ANC packets in a single AV_CODEC_ID_SMPTE_436M_ANC AVPacket's data.
* @param[in] buf Pointer to the data from a AV_CODEC_ID_SMPTE_436M_ANC AVPacket.
* @param[in] buf_size Size of the data from a AV_CODEC_ID_SMPTE_436M_ANC AVPacket.
* @param[out] iter Pointer to the iterator.
* @return 0 on success, AVERROR codes otherwise.
*/
int av_smpte_436m_anc_iter_init(AVSmpte436mAncIterator *iter, const uint8_t *buf, int buf_size);
/**
* Get the next ANC packet from the iterator, advancing the iterator.
* @param[in,out] iter Pointer to the iterator.
* @param[out] anc The returned ANC packet.
* @return 0 on success, AVERROR_EOF when the iterator has reached the end, AVERROR codes otherwise.
*/
int av_smpte_436m_anc_iter_next(AVSmpte436mAncIterator *iter, AVSmpte436mCodedAnc *anc);
/**
* Get the minimum number of bytes needed to store a AVSmpte436mCodedAnc payload.
* @param sample_coding the payload sample coding
* @param sample_count the number of samples stored in the payload
* @return returns the minimum number of bytes needed, on error returns < 0.
* always <= SMPTE_436M_CODED_ANC_PAYLOAD_CAPACITY
*/
int av_smpte_436m_coded_anc_payload_size(AVSmpte436mPayloadSampleCoding sample_coding, uint16_t sample_count);
/**
* Decode a AVSmpte436mCodedAnc payload into AVSmpte291mAnc8bit
* @param[in] sample_coding the payload sample coding
* @param[in] sample_count the number of samples stored in the payload
* @param[in] payload the bytes storing the payload,
* the needed size can be obtained from
avpriv_smpte_436m_coded_anc_payload_size
* @param[in] log_ctx context pointer for av_log
* @param[out] out The decoded ANC packet.
* @return returns 0 on success, otherwise < 0.
*/
int av_smpte_291m_anc_8bit_decode(AVSmpte291mAnc8bit *out,
AVSmpte436mPayloadSampleCoding sample_coding,
uint16_t sample_count,
const uint8_t *payload,
void *log_ctx);
/**
* Fill in the correct checksum for a AVSmpte291mAnc8bit
* @param[in,out] anc The ANC packet.
*/
void av_smpte_291m_anc_8bit_fill_checksum(AVSmpte291mAnc8bit *anc);
/**
* Compute the sample count needed to encode a AVSmpte291mAnc8bit into a AVSmpte436mCodedAnc payload
* @param[in] anc The ANC packet.
* @param[in] sample_coding The sample coding.
* @param[in] log_ctx context pointer for av_log
* @return returns the sample count on success, otherwise < 0.
*/
int av_smpte_291m_anc_8bit_get_sample_count(const AVSmpte291mAnc8bit *anc,
AVSmpte436mPayloadSampleCoding sample_coding,
void *log_ctx);
/**
* Encode a AVSmpte291mAnc8bit into a AVSmpte436mCodedAnc
* @param[in] line_number the line number the ANC packet is on
* @param[in] wrapping_type the wrapping type
* @param[in] sample_coding the payload sample coding
* @param[in] payload the ANC packet to encode.
* @param[in] log_ctx context pointer for av_log
* @param[out] out The encoded ANC packet.
* @return returns 0 on success, otherwise < 0.
*/
int av_smpte_291m_anc_8bit_encode(AVSmpte436mCodedAnc *out,
uint16_t line_number,
AVSmpte436mWrappingType wrapping_type,
AVSmpte436mPayloadSampleCoding sample_coding,
const AVSmpte291mAnc8bit *payload,
void *log_ctx);
/** AVSmpte291mAnc8bit::did when carrying CTA-708 data (for AV_CODEC_ID_EIA_608) */
#define AV_SMPTE_291M_ANC_DID_CTA_708 0x61
/** AVSmpte291mAnc8bit::sdid_or_dbn when carrying CTA-708 data (for AV_CODEC_ID_EIA_608) */
#define AV_SMPTE_291M_ANC_SDID_CTA_708 0x1
/**
* Try to decode an ANC packet into EIA-608/CTA-708 data (AV_CODEC_ID_EIA_608). This
* @param[in] anc The ANC packet.
* @param[in] log_ctx Context pointer for av_log
* @param[out] cc_data the buffer to store the extracted EIA-608/CTA-708 data,
* you can pass NULL to not store the data.
* the required size is 3 * cc_count bytes.
* SMPTE_291M_ANC_PAYLOAD_CAPACITY is always enough size.
* @return returns cc_count (>= 0) on success, AVERROR(EAGAIN) if it wasn't a CTA-708 ANC packet, < 0 on error.
*/
int av_smpte_291m_anc_8bit_extract_cta_708(const AVSmpte291mAnc8bit *anc, uint8_t *cc_data, void *log_ctx);
#endif /* AVCODEC_SMPTE_436M_H */