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bd395904 1 parent aff7a1cb

for #250, the ts packet and adaptation field.

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正在显示 2 个修改的文件 包含 352 行增加 和 4 行删除
... ... @@ -402,6 +402,14 @@ SrsMpegtsFrame::SrsMpegtsFrame()
SrsTsPacket::SrsTsPacket()
{
sync_byte = 0;
transport_error_indicator = 0;
payload_unit_start_indicator = 0;
transport_priority = 0;
pid = SrsTsPidPAT;
transport_scrambling_control = SrsTsScrambledDisabled;
adaption_field_control = SrsTsAdaptationFieldTypeReserved;
continuity_counter = 0;
adaptation_field = NULL;
}
... ... @@ -410,6 +418,46 @@ SrsTsPacket::~SrsTsPacket()
srs_freep(adaptation_field);
}
SrsTsAdaptationField::SrsTsAdaptationField()
{
adaption_field_length = 0;
discontinuity_indicator = 0;
random_access_indicator = 0;
elementary_stream_priority_indicator = 0;
PCR_flag = 0;
OPCR_flag = 0;
splicing_point_flag = 0;
transport_private_data_flag = 0;
adaptation_field_extension_flag = 0;
program_clock_reference_base = 0;
program_clock_reference_extension = 0;
original_program_clock_reference_base = 0;
original_program_clock_reference_extension = 0;
splice_countdown = 0;
transport_private_data_length = 0;
transport_private_data = NULL;
adaptation_field_extension_length = 0;
ltw_flag = 0;
piecewise_rate_flag = 0;
seamless_splice_flag = 0;
ltw_valid_flag = 0;
ltw_offset = 0;
piecewise_rate = 0;
splice_type = 0;
DTS_next_AU0 = 0;
marker_bit0 = 0;
DTS_next_AU1 = 0;
marker_bit1 = 0;
DTS_next_AU2 = 0;
marker_bit2 = 0;
nb_af_ext_reserved = 0;
nb_af_reserved = 0;
}
SrsTsAdaptationField::~SrsTsAdaptationField()
{
}
SrsTSMuxer::SrsTSMuxer(SrsFileWriter* w)
{
writer = w;
... ...
... ... @@ -40,6 +40,7 @@ class SrsFileReader;
class SrsAvcAacCodec;
class SrsCodecSample;
class SrsSimpleBuffer;
class SrsTsAdaptationField;
// Transport Stream packets are 188 bytes in length.
#define SRS_TS_PACKET_SIZE 188
... ... @@ -106,10 +107,6 @@ enum SrsTsAdaptationFieldType
SrsTsAdaptationFieldTypeBoth = 0x03,
};
class SrsTsAdaptationField
{
};
/**
* the packet in ts stream,
* 2.4.3.2 Transport Stream packet layer, hls-mpeg-ts-iso13818-1.pdf, page 36
... ... @@ -118,11 +115,14 @@ class SrsTsAdaptationField
class SrsTsPacket
{
private:
// 1B
/**
* The sync_byte is a fixed 8-bit field whose value is '0100 0111' (0x47). Sync_byte emulation in the choice of
* values for other regularly occurring fields, such as PID, should be avoided.
*/
int8_t sync_byte; //8bits
// 2B
/**
* The transport_error_indicator is a 1-bit flag. When set to '1' it indicates that at least
* 1 uncorrectable bit error exists in the associated Transport Stream packet. This bit may be set to '1' by entities external to
... ... @@ -166,6 +166,8 @@ private:
* Table 2-3).
*/
SrsTsPid pid; //13bits
// 1B
/**
* This 2-bit field indicates the scrambling mode of the Transport Stream packet payload.
* The Transport Stream packet header, and the adaptation field when present, shall not be scrambled. In the case of a null
... ... @@ -207,6 +209,304 @@ public:
};
/**
* the adaption field of ts packet.
* 2.4.3.5 Semantic definition of fields in adaptation field, hls-mpeg-ts-iso13818-1.pdf, page 39
* Table 2-6 ¨C Transport Stream adaptation field, hls-mpeg-ts-iso13818-1.pdf, page 40
*/
class SrsTsAdaptationField
{
private:
// 1B
/**
* The adaptation_field_length is an 8-bit field specifying the number of bytes in the
* adaptation_field immediately following the adaptation_field_length. The value 0 is for inserting a single stuffing byte in
* a Transport Stream packet. When the adaptation_field_control value is '11', the value of the adaptation_field_length shall
* be in the range 0 to 182. When the adaptation_field_control value is '10', the value of the adaptation_field_length shall
* be 183. For Transport Stream packets carrying PES packets, stuffing is needed when there is insufficient PES packet data
* to completely fill the Transport Stream packet payload bytes. Stuffing is accomplished by defining an adaptation field
* longer than the sum of the lengths of the data elements in it, so that the payload bytes remaining after the adaptation field
* exactly accommodates the available PES packet data. The extra space in the adaptation field is filled with stuffing bytes.
*
* This is the only method of stuffing allowed for Transport Stream packets carrying PES packets. For Transport Stream
* packets carrying PSI, an alternative stuffing method is described in 2.4.4.
*/
u_int8_t adaption_field_length; //8bits
// 1B
/**
* This is a 1-bit field which when set to '1' indicates that the discontinuity state is true for the
* current Transport Stream packet. When the discontinuity_indicator is set to '0' or is not present, the discontinuity state is
* false. The discontinuity indicator is used to indicate two types of discontinuities, system time-base discontinuities and
* continuity_counter discontinuities.
*
* A system time-base discontinuity is indicated by the use of the discontinuity_indicator in Transport Stream packets of a
* PID designated as a PCR_PID (refer to 2.4.4.9). When the discontinuity state is true for a Transport Stream packet of a
* PID designated as a PCR_PID, the next PCR in a Transport Stream packet with that same PID represents a sample of a
* new system time clock for the associated program. The system time-base discontinuity point is defined to be the instant
* in time when the first byte of a packet containing a PCR of a new system time-base arrives at the input of the T-STD.
* The discontinuity_indicator shall be set to '1' in the packet in which the system time-base discontinuity occurs. The
* discontinuity_indicator bit may also be set to '1' in Transport Stream packets of the same PCR_PID prior to the packet
* which contains the new system time-base PCR. In this case, once the discontinuity_indicator has been set to '1', it shall
* continue to be set to '1' in all Transport Stream packets of the same PCR_PID up to and including the Transport Stream
* packet which contains the first PCR of the new system time-base. After the occurrence of a system time-base
* discontinuity, no fewer than two PCRs for the new system time-base shall be received before another system time-base
* discontinuity can occur. Further, except when trick mode status is true, data from no more than two system time-bases
* shall be present in the set of T-STD buffers for one program at any time.
*
* Prior to the occurrence of a system time-base discontinuity, the first byte of a Transport Stream packet which contains a
* PTS or DTS which refers to the new system time-base shall not arrive at the input of the T-STD. After the occurrence of
* a system time-base discontinuity, the first byte of a Transport Stream packet which contains a PTS or DTS which refers
* to the previous system time-base shall not arrive at the input of the T-STD.
*
* A continuity_counter discontinuity is indicated by the use of the discontinuity_indicator in any Transport Stream packet.
* When the discontinuity state is true in any Transport Stream packet of a PID not designated as a PCR_PID, the
* continuity_counter in that packet may be discontinuous with respect to the previous Transport Stream packet of the same
* PID. When the discontinuity state is true in a Transport Stream packet of a PID that is designated as a PCR_PID, the
* continuity_counter may only be discontinuous in the packet in which a system time-base discontinuity occurs. A
* continuity counter discontinuity point occurs when the discontinuity state is true in a Transport Stream packet and the
* continuity_counter in the same packet is discontinuous with respect to the previous Transport Stream packet of the same
* PID. A continuity counter discontinuity point shall occur at most one time from the initiation of the discontinuity state
* until the conclusion of the discontinuity state. Furthermore, for all PIDs that are not designated as PCR_PIDs, when the
* discontinuity_indicator is set to '1' in a packet of a specific PID, the discontinuity_indicator may be set to '1' in the next
* Transport Stream packet of that same PID, but shall not be set to '1' in three consecutive Transport Stream packet of that
* same PID.
*
* For the purpose of this clause, an elementary stream access point is defined as follows:
* Video ¨C The first byte of a video sequence header.
* Audio ¨C The first byte of an audio frame.
*
* After a continuity counter discontinuity in a Transport packet which is designated as containing elementary stream data,
* the first byte of elementary stream data in a Transport Stream packet of the same PID shall be the first byte of an
* elementary stream access point or in the case of video, the first byte of an elementary stream access point or a
* sequence_end_code followed by an access point. Each Transport Stream packet which contains elementary stream data
* with a PID not designated as a PCR_PID, and in which a continuity counter discontinuity point occurs, and in which a
* PTS or DTS occurs, shall arrive at the input of the T-STD after the system time-base discontinuity for the associated
* program occurs. In the case where the discontinuity state is true, if two consecutive Transport Stream packets of the same
* PID occur which have the same continuity_counter value and have adaptation_field_control values set to '01' or '11', the
* second packet may be discarded. A Transport Stream shall not be constructed in such a way that discarding such a packet
* will cause the loss of PES packet payload data or PSI data.
*
* After the occurrence of a discontinuity_indicator set to '1' in a Transport Stream packet which contains PSI information,
* a single discontinuity in the version_number of PSI sections may occur. At the occurrence of such a discontinuity, a
* version of the TS_program_map_sections of the appropriate program shall be sent with section_length = = 13 and the
* current_next_indicator = = 1, such that there are no program_descriptors and no elementary streams described. This shall
* then be followed by a version of the TS_program_map_section for each affected program with the version_number
* incremented by one and the current_next_indicator = = 1, containing a complete program definition. This indicates a
* version change in PSI data.
*/
int8_t discontinuity_indicator; //1bit
/**
* The random_access_indicator is a 1-bit field that indicates that the current Transport
* Stream packet, and possibly subsequent Transport Stream packets with the same PID, contain some information to aid
* random access at this point. Specifically, when the bit is set to '1', the next PES packet to start in the payload of Transport
* Stream packets with the current PID shall contain the first byte of a video sequence header if the PES stream type (refer
* to Table 2-29) is 1 or 2, or shall contain the first byte of an audio frame if the PES stream type is 3 or 4. In addition, in
* the case of video, a presentation timestamp shall be present in the PES packet containing the first picture following the
* sequence header. In the case of audio, the presentation timestamp shall be present in the PES packet containing the first
* byte of the audio frame. In the PCR_PID the random_access_indicator may only be set to '1' in Transport Stream packet
* containing the PCR fields.
*/
int8_t random_access_indicator; //1bit
/**
* The elementary_stream_priority_indicator is a 1-bit field. It indicates, among
* packets with the same PID, the priority of the elementary stream data carried within the payload of this Transport Stream
* packet. A '1' indicates that the payload has a higher priority than the payloads of other Transport Stream packets. In the
* case of video, this field may be set to '1' only if the payload contains one or more bytes from an intra-coded slice. A
* value of '0' indicates that the payload has the same priority as all other packets which do not have this bit set to '1'.
*/
int8_t elementary_stream_priority_indicator; //1bit
/**
* The PCR_flag is a 1-bit flag. A value of '1' indicates that the adaptation_field contains a PCR field coded in
* two parts. A value of '0' indicates that the adaptation field does not contain any PCR field.
*/
int8_t PCR_flag; //1bit
/**
* The OPCR_flag is a 1-bit flag. A value of '1' indicates that the adaptation_field contains an OPCR field
* coded in two parts. A value of '0' indicates that the adaptation field does not contain any OPCR field.
*/
int8_t OPCR_flag; //1bit
/**
* The splicing_point_flag is a 1-bit flag. When set to '1', it indicates that a splice_countdown field
* shall be present in the associated adaptation field, specifying the occurrence of a splicing point. A value of '0' indicates
* that a splice_countdown field is not present in the adaptation field.
*/
int8_t splicing_point_flag; //1bit
/**
* The transport_private_data_flag is a 1-bit flag. A value of '1' indicates that the
* adaptation field contains one or more private_data bytes. A value of '0' indicates the adaptation field does not contain any
* private_data bytes.
*/
int8_t transport_private_data_flag; //1bit
/**
* The adaptation_field_extension_flag is a 1-bit field which when set to '1' indicates
* the presence of an adaptation field extension. A value of '0' indicates that an adaptation field extension is not present in
* the adaptation field.
*/
int8_t adaptation_field_extension_flag; //1bit
// if PCR_flag, 6B
/**
* The program_clock_reference (PCR) is a
* 42-bit field coded in two parts. The first part, program_clock_reference_base, is a 33-bit field whose value is given by
* PCR_base(i), as given in equation 2-2. The second part, program_clock_reference_extension, is a 9-bit field whose value
* is given by PCR_ext(i), as given in equation 2-3. The PCR indicates the intended time of arrival of the byte containing
* the last bit of the program_clock_reference_base at the input of the system target decoder.
*/
int64_t program_clock_reference_base; //33bits
//6bits reserved.
int16_t program_clock_reference_extension; //9bits
// if OPCR_flag, 6B
/**
* The optional original
* program reference (OPCR) is a 42-bit field coded in two parts. These two parts, the base and the extension, are coded
* identically to the two corresponding parts of the PCR field. The presence of the OPCR is indicated by the OPCR_flag.
* The OPCR field shall be coded only in Transport Stream packets in which the PCR field is present. OPCRs are permitted
* in both single program and multiple program Transport Streams.
*
* OPCR assists in the reconstruction of a single program Transport Stream from another Transport Stream. When
* reconstructing the original single program Transport Stream, the OPCR may be copied to the PCR field. The resulting
* PCR value is valid only if the original single program Transport Stream is reconstructed exactly in its entirety. This
* would include at least any PSI and private data packets which were present in the original Transport Stream and would
* possibly require other private arrangements. It also means that the OPCR must be an identical copy of its associated PCR
* in the original single program Transport Stream.
*/
int64_t original_program_clock_reference_base; //33bits
//6bits reserved.
int16_t original_program_clock_reference_extension; //9bits
// if splicing_point_flag, 1B
/**
* The splice_countdown is an 8-bit field, representing a value which may be positive or negative. A
* positive value specifies the remaining number of Transport Stream packets, of the same PID, following the associated
* Transport Stream packet until a splicing point is reached. Duplicate Transport Stream packets and Transport Stream
* packets which only contain adaptation fields are excluded. The splicing point is located immediately after the last byte of
* the Transport Stream packet in which the associated splice_countdown field reaches zero. In the Transport Stream packet
* where the splice_countdown reaches zero, the last data byte of the Transport Stream packet payload shall be the last byte
* of a coded audio frame or a coded picture. In the case of video, the corresponding access unit may or may not be
* terminated by a sequence_end_code. Transport Stream packets with the same PID, which follow, may contain data from
* a different elementary stream of the same type.
*
* The payload of the next Transport Stream packet of the same PID (duplicate packets and packets without payload being
* excluded) shall commence with the first byte of a PES packet.In the case of audio, the PES packet payload shall
* commence with an access point. In the case of video, the PES packet payload shall commence with an access point, or
* with a sequence_end_code, followed by an access point. Thus, the previous coded audio frame or coded picture aligns
* with the packet boundary, or is padded to make this so. Subsequent to the splicing point, the countdown field may also
* be present. When the splice_countdown is a negative number whose value is minus n(-n), it indicates that the associated
* Transport Stream packet is the n-th packet following the splicing point (duplicate packets and packets without payload
* being excluded).
*
* For the purposes of this subclause, an access point is defined as follows:
* Video ¨C The first byte of a video_sequence_header.
* Audio ¨C The first byte of an audio frame.
*/
int8_t splice_countdown; //8bits
// if transport_private_data_flag, 1+p[0] B
/**
* The transport_private_data_length is an 8-bit field specifying the number of
* private_data bytes immediately following the transport private_data_length field. The number of private_data bytes shall
* not be such that private data extends beyond the adaptation field.
*/
u_int8_t transport_private_data_length; //8bits
char* transport_private_data; //[transport_private_data_length]bytes
// if adaptation_field_extension_flag, 2+x B
/**
* The adaptation_field_extension_length is an 8-bit field. It indicates the number of
* bytes of the extended adaptation field data immediately following this field, including reserved bytes if present.
*/
u_int8_t adaptation_field_extension_length; //8bits
/**
* This is a 1-bit field which when set to '1' indicates the presence of the ltw_offset
* field.
*/
int8_t ltw_flag; //1bit
/**
* This is a 1-bit field which when set to '1' indicates the presence of the piecewise_rate field.
*/
int8_t piecewise_rate_flag; //1bit
/**
* This is a 1-bit flag which when set to '1' indicates that the splice_type and DTS_next_AU fields
* are present. A value of '0' indicates that neither splice_type nor DTS_next_AU fields are present. This field shall not be
* set to '1' in Transport Stream packets in which the splicing_point_flag is not set to '1'. Once it is set to '1' in a Transport
* Stream packet in which the splice_countdown is positive, it shall be set to '1' in all the subsequent Transport Stream
* packets of the same PID that have the splicing_point_flag set to '1', until the packet in which the splice_countdown
* reaches zero (including this packet). When this flag is set, if the elementary stream carried in this PID is an audio stream,
* the splice_type field shall be set to '0000'. If the elementary stream carried in this PID is a video stream, it shall fulfil the
* constraints indicated by the splice_type value.
*/
int8_t seamless_splice_flag; //1bit
//5bits reserved
// if ltw_flag, 2B
/**
* (legal time window_valid_flag) ¨C This is a 1-bit field which when set to '1' indicates that the value of the
* ltw_offset shall be valid. A value of '0' indicates that the value in the ltw_offset field is undefined.
*/
int8_t ltw_valid_flag; //1bit
/**
* (legal time window offset) ¨C This is a 15-bit field, the value of which is defined only if the ltw_valid flag has
* a value of '1'. When defined, the legal time window offset is in units of (300/fs) seconds, where fs is the system clock
* frequency of the program that this PID belongs to, and fulfils:
* offset = t1(i) ¨C t(i)
* ltw_offset = offset//1
* where i is the index of the first byte of this Transport Stream packet, offset is the value encoded in this field, t(i) is the
* arrival time of byte i in the T-STD, and t1(i) is the upper bound in time of a time interval called the Legal Time Window
* which is associated with this Transport Stream packet.
*/
int16_t ltw_offset; //15bits
// if piecewise_rate_flag, 3B
//2bits reserved
/**
* The meaning of this 22-bit field is only defined when both the ltw_flag and the ltw_valid_flag are set
* to '1'. When defined, it is a positive integer specifying a hypothetical bitrate R which is used to define the end times of
* the Legal Time Windows of Transport Stream packets of the same PID that follow this packet but do not include the
* legal_time_window_offset field.
*/
int32_t piecewise_rate; //22bits
// if seamless_splice_flag, 5B
/**
* This is a 4-bit field. From the first occurrence of this field onwards, it shall have the same value in all the
* subsequent Transport Stream packets of the same PID in which it is present, until the packet in which the
* splice_countdown reaches zero (including this packet). If the elementary stream carried in that PID is an audio stream,
* this field shall have the value '0000'. If the elementary stream carried in that PID is a video stream, this field indicates the
* conditions that shall be respected by this elementary stream for splicing purposes. These conditions are defined as a
* function of profile, level and splice_type in Table 2-7 through Table 2-16.
*/
int8_t splice_type; //4bits
/**
* (decoding time stamp next access unit) ¨C This is a 33-bit field, coded in three parts. In the case of
* continuous and periodic decoding through this splicing point it indicates the decoding time of the first access unit
* following the splicing point. This decoding time is expressed in the time base which is valid in the Transport Stream
* packet in which the splice_countdown reaches zero. From the first occurrence of this field onwards, it shall have the
* same value in all the subsequent Transport Stream packets of the same PID in which it is present, until the packet in
* which the splice_countdown reaches zero (including this packet).
*/
int8_t DTS_next_AU0; //3bits
int8_t marker_bit0; //1bit
int16_t DTS_next_AU1; //15bits
int8_t marker_bit1; //1bit
int16_t DTS_next_AU2; //15bits
int8_t marker_bit2; //1bit
// left bytes.
/**
* This is a fixed 8-bit value equal to '1111 1111' that can be inserted by the encoder. It is discarded by the
* decoder.
*/
int nb_af_ext_reserved;
// left bytes.
/**
* This is a fixed 8-bit value equal to '1111 1111' that can be inserted by the encoder. It is discarded by the
* decoder.
*/
int nb_af_reserved;
public:
SrsTsAdaptationField();
virtual ~SrsTsAdaptationField();
public:
};
/**
* write data from frame(header info) and buffer(data) to ts file.
* it's a simple object wrapper for utility from nginx-rtmp: SrsMpegtsWriter
*/
... ...