Pulse or digital communications – Bandwidth reduction or expansion – Television or motion video signal
Reexamination Certificate
1998-04-16
2001-12-25
Kelley, Chris (Department: 2713)
Pulse or digital communications
Bandwidth reduction or expansion
Television or motion video signal
Reexamination Certificate
active
06333950
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for variable length encoding of image data and transmission encoding in accordance with a transmission path and, more particularly, to a multiplexing process of variable length encoding data and transmission synchronous information.
2. Related Background Art
In recent years, a digital processing system according to the MPEG (Moving Picture Experts Group) 2 standard [ISO/IEC (International Organization for Standardization/International Electrotechnical Commission) 13818-1 to 13818-3] is becoming a standard of a video transmitting system.
FIG. 1
is a block diagram showing a construction on the transmitting side of a general digital transmitting apparatus according to ISO/IEC 13818-1 to 13818-3.
In
FIG. 1
, reference numeral
301
denotes a video encoder for compressing digital video data so as to conform with ISO/IEC 13818-2;
302
an audio encoder for compressing a digital audio signal so as to conform with ISO/IEC 13818-3;
303
a packetizer for packetizing a video elementary stream as an output of the video encoder in accordance with the PES (Packetized Elementary Stream) of ISO/IEC 13818-1; and
304
a packetizer for packetizing an audio elementary stream as an output of the audio encoder in accordance with the PES of ISO/IEC 13818-1.
Reference numeral
305
denotes a TS (Transport Stream) multiplexer for packetizing a video PES and an audio PES as outputs of the packetizers into transport stream packets in accordance with the TS (Transport Stream) of ISO/IEC 13818-1 and multiplexing them.
The transmitting operation of the digital transmitting apparatus constructed as mentioned above will now be described hereinbelow.
The video data and audio data are inputted to the video encoder
301
and audio encoder
302
, respectively. In the video encoder
301
, information whose correlation is high with respect to the space and time is checked and converted into data of a low redundancy in accordance with ISO/IEC 13818-2, thereby compressing an information amount.
In the audio encoder
302
, information whose correlation is high with regard to the time is checked and converted into data of a low redundancy in accordance with ISO/IEC 13818-3, thereby compressing an information amount. A unit which can be solely decompressed in those compressed data trains is called an access unit (AU), data trains of the video AU and audio AU are called a video elementary stream (video ES) and an audio elementary stream (audio ES), respectively.
The video ES and audio ES are respectively inputted to the packetizers
303
and
304
and are packetized (PES) to variable length packets generally on a unit basis in which the access unit is set to a reference together with a stream ID indicative of an attribute of the ES, time stamp information showing a decoding time and a display time on the decoding side, and the like.
The TS multiplexer
305
receives the video PES and audio PES, converts into transport streams (TS), and outputs.
FIG. 2
is a block diagram showing a detailed construction of the TS multiplexer
305
.
In
FIG. 2
, each of the video PES and audio PES is accumulated in each buffer and is packetized on a unit basis for transmitting data. This packet is called a transport stream packet (TS packet). In ISO/IEC 13818-1, the TS packet has a size of 188 bytes and includes a header including a sync byte which is necessary to reconstruct the TS packet on the decoding side, a PID (Packet Identification) showing the ID of the TS packet, and the like, an adaptation field in which annexed information which is necessary to transmit PCR (Program Clock Reference) showing a reference time to specify a receiving time on the decoding side and the like are described, and the other space area (payload) into which the video PES or audio PES is stored. On the other hand, synthetic annexed information of the TS such as definition of the PID or the like is formed as PSI (Program Specific Information), is stored into a buffer, and is packetized to a TS packet having the PID which has previously been defined.
As for the PCR, since it has to be outputted as a TS within a period of time of 100 msec, generally, the PID for PCR is defined by PSI separately from the packets to transmit the video PES and audio PES and is packetized as a TS packet constructed by only the packet header including the PID and the adaptation field.
Each TS packet is read out from each buffer at a proper timing on a TS packet unit basis and is outputted as TS.
According to the multiplexing method of data in the digital transmitting apparatus as mentioned above, there is a large limitation in an amount of data which is transmitted onto the transmitting path, the transmitting path cannot be effectively used, and a vain stuffing data always has to be multiplexed.
For example, when the video PES shown in
FIG. 3
is converted into the TS packet, the adaptation field is inserted into the last TS packet and the vain stuffing byte (dummy data bytes for making a packet data length constant) have to be multiplexed.
Even in case of transmitting the independent TS packet for the transmission of PCR as shown in
FIG. 4
, the stuffing process is necessary in the TS packet.
SUMMARY OF THE INVENTION
In consideration of the background as mentioned above, it is an object of the invention to provide encoding apparatus and method which can solve the above-mentioned problems in a conventional data multiplexing method and can effectively use a transmission path and, further, is strong against a transmission error and to provide a recording medium in which a transmitting program has been recorded.
To accomplish the above object, according to a preferred embodiment of the invention, there is provided an encoding apparatus/method comprising the steps of: inputting first information data which was variable length encoded; variable length packetizing the first information data by a plurality of data trains; generating second information data concerning the first information data; multiplexing the first information data which was variable length packetized and the generated second information data to a plurality of packets of a fixed length; detecting the packet length of the information train which was variable length packetized; and controlling a multiplexing process to the packets of the fixed length in accordance with the detection result.
According to another preferred embodiment of the invention, there is provided an encoding apparatus/method comprising the steps of: inputting first information data which was variable length encoded; variable length packetizing the first information data by a plurality of data trains; generating second information data concerning the first information data; multiplexing the first information data which was variable length packetized and the generated second information data to a plurality of packets of a fixed length; counting an elapsed time required for the multiplexing of the second information data; detecting the packet length of the information train which was variable length packetized; and controlling a multiplexing process to the packets of the fixed length in accordance with the count result and the detection result.
According to still another preferred embodiment of the invention, there is provided a computer readable recording medium in which an encoding program has been recorded, comprising: a code of an inputting step of inputting first information data which was variable length encoded; a code of a first packetizing step of variable length packetizing the first information data by a plurality of data trains; a code of a generating step of generating second information data concerning the first information data; a code of a second packetizing step of multiplexing the first information data which was variable length packetized by the first packetizing step and the second information data generated by the generating step to a plurality of packets of a fixed length; a code of a detecting step of detecting the p
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Kelley Chris
Philippe Gims
LandOfFree
Encoding apparatus and method and computer readable... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Encoding apparatus and method and computer readable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Encoding apparatus and method and computer readable... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2586609