Personal video recorder

Apparatus for creating a bitstream in which a sequence of picture slices is encoded as reference slices and non-reference slices, wherein the reference slices include a plurality of B slices, said apparatus comprising a means for performing a method comprising:

• for B each slice, forming at least one data packet containing data values derived from brightness and color information pertaining to the slice, and
• for each B slice, including in the at least one packet a header element reflecting whether the B slice is a reference slice,
• said header element containing a value that indicates where in a hierarchy of discardability the B slice is,
• said hierarchy of discardability comprising a ranking of the plurality of B slices by how much degradation to the sequence of picture slices will be experienced by a discarding of each B slice.

Apparatus for decoding a bitstream conveying a sequence of pictures each containing at least one picture slice, wherein each picture slice is encoded as a reference slice or a non-reference slice, the reference slices include B slices, and bits of each reference B slice are conveyed by at least one data packet that includes a header element having a value, the apparatus comprising a means for performing a method comprising:

• receiving a trick play command calling for pictures to be discarded without being presented,
• selecting a reference B picture to be discarded based on the value of the header element,
• said value indicating where in a hierarchy of discardability a B slice is,
• said hierarchy of discardability comprising a ranking of the B slices by how much degradation to the sequence of picture slices will be experienced by a discarding of each B slice.

A non-transitory computer readable medium containing instructions that, when executed by a computing machine receiving a bitstream in which a sequence of picture slices is encoded as reference slices and non-reference slices, wherein the reference slices include a plurality of B slices, cause the computing machine to perform a method comprising:

• for each B slice, forming at least one data packet containing data values derived from brightness and color information pertaining to the slice, and
• for each B slice, including in the at least one data packet a header element indicating whether the B slice is a reference slice,
• said value indicating where in a hierarchy of discardability a B slice is,
• said hierarchy of discardability comprising a ranking of the plurality of B slices by how much degradation to the sequence of picture slices will be experienced by a discarding of each B slice.

A method of assisting in trick play operation of a video recording and playback device, comprising:

• at a transmitting location,
• encoding, using an advanced video coding (AVC) encdoder, a sequence of pictures, each containing at least one picture slice, selectively in either a normal mode or a trick play assist mode, and
• in the trick play assist mode, encoding each slice as one of at least two different types depending on prediction needed to decode the slice, for each slice of at least one type, forming at least one data packet containing data values derived from image information pertaining to the slice, creating at least one data value for each slice of said one type,
• said value indicating where in a hierarchy of discardability the B slice is,
• said hierarchy of discardability comprising a ranking of the B slices by how much degradation to the sequence of picture slices will be experienced by a discarding of each B slice,
• at the receiving location,
• extracting data packets from the transport stream and temporarily storing the data packets for later playback in normal operation or trick play operation, and
• in trick play operation, detecting, using an advanced video coding (AVC) decoder, whether the sequence of picture slices was encoded in the trick play assist mode and, if so, selectively discarding pictures depending on said data values.

A method of creating a bitstream in which a sequence of picture slices is encoded as slices of at least two different types depending on prediction needed to decode the slice, said method comprising:

• for each slice of at least one type, forming at least one data packet containing data values derived from brightness and color information pertaining to the slice, and
• for a slice of said one type, including in the at least one data packet a header element indicating whether the slice is a reference slice, and
• wherein in the event that said slice is a reference slice the header element has a value,
• said value indicating where in a hierarchy of discardability the reference slice is,
• said hierarchy of discardability comprising a ranking of the reference slices of the sequence by how much degradation to the sequence of picture slices will be experienced by a discarding of each B slice.