Methods and systems for high dynamic range video coding
Embodiments of the present invention comprise methods and systems for high dynamic range (HDR) video coding and decoding that is backwards-compatible with one or more standard dynamic range (SDR) encoding and decoding techniques, through the transmission of HDR residual data used to reconstruct an encoded HDR sequence from an inverse-tone-mapped SDR sequence.
1. A method for transmitting encoded video data, said method comprising:
a) receiving a high dynamic range (HDR) image sequence;
b) tone mapping a standard dynamic range (SDR) image sequence from said received HDR image sequence;
c) encoding said mapped SDR image sequence with an SDR encoder;
d) transmitting said encoded SDR image sequence to a recipient;
e) decoding said encoded SDR image sequence;
f) inverse tone mapping the decoded SDR image sequence to form decoded HDR sequence data;
g) encoding said decoded SDR image sequence, said decoded HDR sequence data and said received HDR image sequence to form HDR residual data, said HDR residual data being the difference between said decoded HDR sequence data and said received HDR image sequence; and
h) transmitting said HDR residual data to said recipient.
2. The method of claim 1 further comprising storing said encoded SDR image sequence and said HDR residual data on a storage device.
3. The method of claim 1 wherein said SDR encoder is an MPEG-2 encoder.
4. The method of claim 1 wherein said SDR encoder is an H.264 encoder.
5. The method of claim 1 wherein transmitting said encoded SDR image sequence and transmitting said HDR residual data are multiplexed in a single transmission.
6. The method of claim 1 wherein said encoded SDR image sequence is decoded independently of said HDR residual data.
7. A video codec, said codec comprising:
a) a receiver for receiving a high dynamic range (HDR) image sequence;
b) a standard dynamic range (SDR) tone mapper for mapping a standard dynamic range (SDR) image sequence from said received HDR image sequence;
c) an SDR encoder for encoding said mapped SDR image sequence;
d) a decoder for decoding said encoded SDR image sequence;
e) an inverse tone mapper for converting said decoded SDR image sequence into a decoded HDR sequence;
f) an HDR residual encoder for combining the decoded SDR image sequence, said decoded HDR sequence and said received HDR image sequence to form HDR residual data, said HDR residual data being the difference between said decoded HDR sequence and said received HDR image sequence; and
g) a transmitter for transmitting said encoded SDR image sequence and said HDR residual data to a destination.