Systems and methods for caching multimedia data
View Patent ↗Systems and methods are provided for caching media data to thereby enhance media data read and/or write functionality and performance. A multimedia apparatus, comprises a cache buffer configured to be coupled to a storage device, wherein the cache buffer stores multimedia data, including video and audio data, read from the storage device. A cache manager coupled to the cache buffer, wherein the cache buffer is configured to cause the storage device to enter into a reduced power consumption mode when the amount of data stored in the cache buffer reaches a first level.
1. A multimedia playback apparatus, comprising:
a mass storage device having a multiplicity of blocks of multimedia data stored thereon, said multimedia data including video and audio data;
a cache buffer coupled to said mass storage device for storing a plurality of blocks of said multimedia data read from said mass storage device, said cache buffer having a capacity for storing a first amount of said multimedia data;
a track buffer coupled to said cache buffer and having a storage capacity for storing a second amount of said multimedia data read from said cache buffer; and
a cache manager coupled to said cache buffer and said track buffer for controlling transfer of said multimedia data from said mass storage device to said cache buffer and from said cache buffer to said track buffer, said cache manager responding to a read request of a particular block of multimedia data fetches said requested block of multimedia data from said mass storage device and fetches additional blocks of multimedia data anticipated being subject to future read requests to substantially fill said cache buffer for transfer to said track buffer and said mass storage device enters a reduced power consumption mode responsive to said cache buffer being filled with a plurality of untransferred blocks of multimedia data to a first threshold level, said mass storage device exiting said reduced power consumption mode responsive to said plurality of untransferred blocks of multimedia data being below a second threshold level, said cache manager replacing blocks of transferred multimedia data in accordance with a priority hierarchy based on at least one characteristic of said blocks of multimedia data.
2. The multimedia playback apparatus as defined in claim 1 , further comprising:
a demultiplex circuit coupled to said track buffer for receiving said multimedia data therefrom;
a decode circuit coupled to said demultiplex circuit for receiving said multimedia data from said demultiplex circuit to produce decoded multimedia data; and
a render circuit coupled to said decode circuit for rendering said decoded multimedia data.
3. The multimedia playback apparatus as defined in claim 1 , wherein said reduced power consumption mode idles said mass storage device.
4. The multimedia playback apparatus as defined in claim 1 , wherein said reduced power consumption mode spins down a rotary portion of said mass storage device.
5. The multimedia playback apparatus as defined in claim 1 , wherein said cache manager causes said mass storage device to transfer a requested block of multimedia data from said mass storage device to said track buffer responsive to said priority hierarchy failing to be exceeded.
6. The multimedia playback apparatus as defined in claim 1 , wherein said cache buffer is formed by a volatile memory.
7. The multimedia playback apparatus as defined in claim 1 , wherein said mass storage device is an optical storage drive selected from a group consisting of a DVD drive and a CD drive.
8. The multimedia playback apparatus as defined in claim 1 , wherein said mass storage device is a digital tape drive.
9. The multimedia playback apparatus as defined in claim 1 , wherein said mass storage device is disposed in a computer.
10. The multimedia playback apparatus as defined in claim 1 , wherein said mass storage device is disposed in an electronic consumer product, including at least one of a set-top box.
11. The multimedia playback apparatus as defined in claim 1 , wherein said cache manager is configured to retain an address mapping of said plurality of blocks of said multimedia data that is stored in said cache buffer.
12. A method of controlling a multimedia storage device, the method comprising: providing a rotating media storage drive with a multiplicity of blocks of multimedia data stored thereon; providing a cache memory and a track buffer; transferring said plurality of blocks of multimedia data read from said rotating media storage drive into said cache memory and from said cache memory to said track buffer responsive to a read request for one of the plurality of blocks of multimedia data; transferring additional blocks of said plurality of blocks of multimedia data anticipated being subject to future read requests to substantially fill said cache memory for transfer to said track buffer; placing said rotating media storage drive in a reduced power consumption mode responsive to said cache memory being filled with a plurality of untransferred blocks of multimedia data to a first threshold level; taking said rotating media storage drive out of said reduced power consumption mode responsive to said plurality of untransferred blocks of multimedia data being below a second threshold level; replacing blocks of transferred multimedia data in accordance with a priority hierarchy based on at least one characteristic of said blocks of multimedia data; receiving a scan command; and if said multimedia data corresponding to said scan command is stored in said cache memory, transferring said corresponding multimedia data from said cache memory to said track buffer for subsequent rendering.
13. The method as defined in claim 12 , wherein said scan command is one of a fast forward command and a fast reverse command.
14. The method as defined in claim 12 , further comprising:
receiving a second scan command; and
reading multimedia data corresponding to said second scan command from said rotating media storage device when said multimedia data corresponding to the second scan command is not stored in said cache memory.
15. The method as defined in claim 12 , wherein sub-band data is stored in said cache memory in synchronization with said plurality of blocks of multimedia data.
16. The method as defined in claim 12 , wherein said corresponding multimedia data is transferred from said cache to said track buffer by modifying a pointer value.
17. A method of processing multimedia data, comprising:
determining that multimedia data is to be read from a rotating media storage device;
transferring a quantity of multimedia data from said rotating media storage device to a cache memory responsive to a read request for a first portion of said quantity of multimedia data, a remaining portion of said quantity of multimedia data being multimedia data anticipated being subject to future read requests;
responsive to said first quantity of said multimedia data being stored in said cache memory, ceasing further transfer of said multimedia data from said rotating media storage device into said cache memory and causing said rotating media storage device to spin down and thereby enter into a power saving mode;
sequentially writing portions of said quantity of multimedia data from said cache memory to a track buffer for subsequent rendering; and
at least partly in response to a portion of said quantity of multimedia data yet to be written to said track buffer stored in said cache memory falling below a threshold value, causing said rotating media storage device to spin up and thereby exit said power saving mode.
18. The method as defined in claim 17 , wherein said remaining portion of said quantity of multimedia data includes a plurality of views of at least one image stored in said cache memory.
19. The method as defined in claim 17 , wherein the step of sequentially writing is followed by the step of maintaining said quantity of multimedia data in said cache memory subsequent to being rendered for facilitating a scan command without rereading said multimedia data stored on rotating media storage device.
20. The method as defined in claim 17 , wherein the step of sequentially writing includes the step of maintaining a DVD menu in said cache memory during playback of a movie stored on said rotating media storage device so that said DVD menu can be accessed without rereading said DVD menu from said rotating media storage device.
21. The method as defined in claim 17 , wherein said remaining portion of said quantity of multimedia data includes menu data and video data.