Systems and methods for processing program content and information in a video broadcast
View Patent ↗Embodiments of the present invention significantly decrease the processing requirements as well as the cost of digital television receivers. In an embodiment, processing requirements of both hardware and software components in digital television receivers are lowered by generating the channel map without regard to channel map information present in a Virtual Channel Table (VCT). In another embodiment, significant recurring portions of an ATSC signal can be neglected with no processing power, cost, and time spent thereon. In another embodiment, processing typically used to process channel map information contained in the VCT portion of the ATSC signal is freed and may instead be used to process other information, thereby enabling further enhancements and features in digital television services.
1. A method of processing a packetized stream containing program content and information corresponding to a broadcast channel associated with one or more virtual channels, comprising:
(a) receiving a transport packet of the packetized stream in a first-in-first-out (FIFO) memory;
(b) sequentially reading contents of the transport packet from the FIFO memory;
(c) detecting a start of a Virtual Channel Table (VCT) in the read contents of the transport packet, wherein the VCT includes channel information associated with the one or more virtual channels;
(d) if no VCT is detected in step (c), writing the read contents of the transport packet to a buffer;
(e) if a start of a VCT is detected in step (c), for each virtual channel represented in the VCT, discarding, from the FIFO memory without reading, bits representative of channel descriptors of the virtual channel, and writing replacement bits having equal bit length as the discarded bits to the buffer; and
(f) generating a channel map useable in displaying the broadcast channels using only contents of the buffer.
2. The method of claim 1 , wherein detecting a start of a VCT in the read contents of the transport packet comprises detecting a “table id” field having a value representative of a VCT.
3. The method of claim 1 , wherein step (e) further comprises, for each virtual channel represented in the VCT:
(g) reading a “descriptors length” field having a value representative of a number of bits of channel descriptors immediately following the “descriptors length” field; and
(h) writing replacement bits to the buffer having a bit length equal to the value of the “descriptors length” field.
4. The method of claim 3 , further comprising:
if a start of a VCT is detected in step (c), after reading the “descriptors length” field in step (g), incrementing a read pointer of the FIFO by an equal number of bits as the value of the “descriptors length” field.
5. The method of claim 1 , wherein step (e) further comprises, for each virtual channel represented in the VCT, for each channel descriptor in the VCT:
(g) reading a “descriptor length” field having a value representative of a number of bits of channel descriptor data immediately following the “descriptor length” field; and
(h) writing replacement bits to the buffer having a bit length equal to the value of the “descriptor length” field.
6. The method of claim 5 , further comprising:
if a start of a VCT is detected in step (c), after reading the “descriptor length” field in step (g), incrementing a read pointer of the FIFO by an equal number of bits as the value of the “descriptor length” field.
7. The method of claim 1 , wherein the replacement bits include zero bits.
8. The method of claim 1 , wherein the replacement bits include dummy stuffing bits.
9. The method of claim 8 , wherein the replacement bits include up to four dummy channel descriptors.
10. The method of claim 1 , wherein the discarded bits include bits representative of a Service Location Descriptor (SLD) of the virtual channel.
11. The method of claim 1 , wherein the transport packet is encoded according to the MPEG-2 (“Moving Pictures Expert Group-2”) standard.
12. The method of claim 1 , wherein the contents of the buffer include bits equivalent to the received transport packet with any bits representative of channel descriptors of a VCT initially in the received transport packet replaced with replacement bits.
13. The method of claim 1 , wherein the contents of the buffer include bits equivalent to ATSC (Advanced Television Systems Committee) table sections with any bits representative of channel descriptors of a VCT initially received in the packetized stream replaced with replacement bits.
14. The method of claim 1 , wherein steps (a)-(f) are performed using a combination of hardware and software components of a digital television receiver.
15. The method of claim 1 , wherein steps (a)-(e) are performed using hardware components and step (f) is performed using software components of a digital television receiver.
16. A receiver useable to process a packetized stream containing program content and information corresponding to a broadcast channel associated with one or more virtual channels, comprising:
a first-in-first-out (FIFO) memory configured to receive a transport packet of the packetized stream; and
a micro-code engine configured to sequentially read contents of the transport packet from the FIFO and to detect a start of a Virtual Channel Table (VCT) in the read contents of the transport packet, wherein the VCT includes channel information associated with the one or more virtual channels;
wherein the micro-code engine is further configured so that, if no VCT is detected in the read contents of the transport packet, to write the read contents of the transport packet to a buffer, and
wherein the micro-code engine is further configured so that, if a start of a VCT is detected, for each virtual channel represented in the VCT, to discard, from the FIFO memory without reading, bits representative of channel descriptors of the virtual channel, and to write replacement bits having equal bit length as the discarded bits to the buffer; and
means for generating a channel map useable in displaying the broadcast channels using only contents of the buffer.
17. The receiver of claim 16 , wherein the replacement bits include zero bits.
18. The receiver of claim 16 , wherein the replacement bits include dummy stuffing bits.
19. The receiver of claim 18 , wherein the replacement bits include up to four dummy channel descriptors.
20. The receiver of claim 16 , wherein the discarded bits include bits representative of a Service Location Descriptor (SLD) of the virtual channel.
21. The receiver of claim 16 , wherein the transport packet is encoded according to the MPEG-2 (“Moving Pictures Expert Group-2”) standard.
22. A method of processing a packetized stream containing program content and information corresponding to a broadcast channel associated with one or more virtual channels, comprising:
(a) receiving a transport packet of the packetized stream in a first-in-first-out (FIFO) memory;
(b) sequentially reading contents of the transport packet from the FIFO memory;
(c) detecting a start of a Virtual Channel Table (VCT) in the read contents of the transport packet, wherein the VCT includes channel information associated with the one or more virtual channels;
(d) if no VCT is detected in step (c), writing the read contents of the transport packet to a buffer;
(e) if a start of a VCT is detected in step (c), for each virtual channel represented in the VCT, discarding, from the FIFO memory without reading, bits representative of channel descriptors of the virtual channel and modifying a “descriptors length” field having a value representative of the length of said bits to have a value of zero; and
(f) generating a channel map useable in displaying the broadcast channels using only contents of the buffer.
23. The method of claim 22 , further comprising:
modifying a “section length” field having a value representative of a number of bits in the table section immediately following said “section length” field to account for said modified “descriptors length” field.