jpeg_transport.h File Reference

An RTP/JPEG (Motion JPEG) data transport. More...

#include <smolrtsp/droppable.h>
#include <smolrtsp/jpeg.h>
#include <smolrtsp/rtp_transport.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <slice99.h>
#include <smolrtsp/priv/compiler_attrs.h>

Include dependency graph for jpeg_transport.h:

Go to the source code of this file.

Data Structures
struct	SmolRTSP_JpegTransportConfig
	The configuration structure for SmolRTSP_JpegTransport. More...
struct	SmolRTSP_JpegFrame
	One Motion-JPEG frame, ready to packetize per RFC 2435. More...

Typedefs
typedef struct SmolRTSP_JpegTransport	SmolRTSP_JpegTransport
	An RTP/JPEG data transport.

Functions
SmolRTSP_JpegTransportConfig	SmolRTSP_JpegTransportConfig_default (void) SMOLRTSP_PRIV_MUST_USE
	Returns the default SmolRTSP_JpegTransportConfig (SMOLRTSP_MAX_JPEG_PACKET_SIZE).
SmolRTSP_JpegTransport *	SmolRTSP_JpegTransport_new (SmolRTSP_RtpTransport *t) SMOLRTSP_PRIV_MUST_USE
	Creates a new RTP/JPEG transport with the default configuration.
SmolRTSP_JpegTransport *	SmolRTSP_JpegTransport_new_with_config (SmolRTSP_RtpTransport *t, SmolRTSP_JpegTransportConfig config) SMOLRTSP_PRIV_MUST_USE
	Creates a new RTP/JPEG transport with a custom configuration.
int	SmolRTSP_JpegTransport_send_frame (SmolRTSP_JpegTransport *self, SmolRTSP_RtpTimestamp ts, SmolRTSP_JpegFrame frame) SMOLRTSP_PRIV_MUST_USE
	Sends one Motion-JPEG frame as a sequence of RTP packets.
	declImplExtern99 (SmolRTSP_Droppable, SmolRTSP_JpegTransport)
	Implements SmolRTSP_Droppable_IFACE for SmolRTSP_JpegTransport.
bool	SmolRTSP_JpegTransport_is_full (SmolRTSP_JpegTransport *self)

Detailed Description

An RTP/JPEG (Motion JPEG) data transport.

See also

RTP Payload Format for JPEG-compressed Video: https://datatracker.ietf.org/doc/html/rfc2435

Function Documentation

declImplExtern99()

declImplExtern99	(	SmolRTSP_Droppable	,
		SmolRTSP_JpegTransport
	)

Implements SmolRTSP_Droppable_IFACE for SmolRTSP_JpegTransport.

See Interface99 for the macro usage.

SmolRTSP_JpegTransport_new()

SmolRTSP_JpegTransport * SmolRTSP_JpegTransport_new

(

SmolRTSP_RtpTransport *

t

)

Creates a new RTP/JPEG transport with the default configuration.

Parameters

[in]

t

The underlying RTP transport.

Precondition

t != NULL.

SmolRTSP_JpegTransport_new_with_config()

SmolRTSP_JpegTransport * SmolRTSP_JpegTransport_new_with_config	(	SmolRTSP_RtpTransport *	t,
		SmolRTSP_JpegTransportConfig	config
	)

Creates a new RTP/JPEG transport with a custom configuration.

Parameters

[in]	t	The underlying RTP transport.
[in]	config	The transmission configuration structure.

Precondition

t != NULL.

config.max_packet_size > SMOLRTSP_JPEG_MAIN_HEADER_SIZE.

SmolRTSP_JpegTransport_send_frame()

int SmolRTSP_JpegTransport_send_frame	(	SmolRTSP_JpegTransport *	self,
		SmolRTSP_RtpTimestamp	ts,
		SmolRTSP_JpegFrame	frame
	)

Sends one Motion-JPEG frame as a sequence of RTP packets.

The library splits SmolRTSP_JpegFrame::scan_data across as many RTP packets as needed and builds the RFC 2435 §3.1 main header per packet, stamping SmolRTSP_JpegPayloadHeader.fragment_offset with the byte offset inside the scan data carried by each packet. The first packet of the frame also carries the quantization-table block (when SmolRTSP_JpegFrame::qt0 / SmolRTSP_JpegFrame::qt1 are non-empty). The RTP marker bit is set on the final packet of the frame.

Parameters

[in]	self	The transport.
[in]	ts	The RTP timestamp shared by every packet of the frame.
[in]	frame	The Motion-JPEG frame to send.

Precondition

self != NULL.

frame.qt0.len + frame.qt1.len <= 0xFFFF (fits the QT header Length field).

config.max_packet_size is large enough to carry one main JPEG header plus the QT block (when present) plus at least one byte of scan data on the first packet – a single-byte first packet is otherwise unrepresentable.

Returns

0 on success; -1 on I/O error (with errno set by the underlying transport's send).