Method to encode video with close multiple scene changes
View Patent ↗A video encoding method is provided when three scenes are separated by two closely spaced scene changes. For scene changes spaced greater than a threshold, scene changes are programmed with I frames in a normal fashion. If less than the threshold, the method encodes depending on complexity of the first, second and third scene to determine how to encode the scene changes. To compare complexities, the process begins by using X 1 , X 2 , and X 3 to note respectively the complexities of the first, the second and the third scenes. If the absolute difference of X 1 and X 2 is higher than a first threshold and the absolute difference of X 2 and X 3 is higher than a second threshold, the first scene change is more significant than the second scene change, so in that case the process encodes the first scene change as an I-frame and picks a quantization parameter (QP) based on the complexity blended from the complexity of scene 2 (X 2 ) and scene 3 (X 3 ).
1. A method for encoding video having at least two close successive scene changes comprising:
obtaining video frames provided to an encoder;
determining scene change frames in the video frames;
determining when a first scene change frame and a second scene change frame occur greater than a first threshold number of frames apart, and when so providing information for the encoder to encoding the first and second scene changes in a normal fashion;
determining that the first scene change frame and the second scene change frame occur less than the first threshold number of frames, and when so performing the following steps:
determining a complexity of a first scene (X 1 ), a second scene (X 2 ) and a third scene (X 3 ), wherein the X 1 , X 2 and X 3 are separated by the first and the second scene change frames;
determining when an absolute difference between the complexity of X 1 and X 2 is greater than a first complexity threshold Xth1 and the absolute difference of the complexity of X 2 and X 3 is less than a second complexity threshold Xth2, and when so encoding the first scene change frame as a scene change I frame, but picking a quantization parameter (QP) based on a complexity that is blended from the complexity of X 2 and X 3 .
2. The method of claim 1 , wherein the third scene after the second scene change is then encoded with its proper QP when the blended complexity is used.
3. The method of claim 1 , wherein an equivalent P frame with mostly intra blocks is encoded for the second change when the blended complexity is used.
4. The method of claim 1 , further comprising:
determining when an absolute difference between the complexity of X 1 and X 2 is greater than the first complexity threshold Xth1 and the absolute difference of the complexity of X 2 and X 3 is greater than the second complexity threshold Xth1, and when so encoding the first scene change frame and the second scene change frame as a scene change I frame.
5. The method of claim 4 , further comprising:
determining when an absolute difference between the complexity of X 1 and X 2 is less than the second complexity threshold Xth2 and the absolute difference of the complexity of X 2 and X 3 is less than the second complexity threshold Xth2, and when so ignoring the first scene change frame and encoding the second scene change frame as a scene change I frame.
6. An apparatus to encode video frames, the apparatus comprising:
an encoder having a first input for receiving video frames to be processed and a second input for receiving parameter data to enable the encoder to allocate bits for frames for encoding;
a statistical analysis processor that receives the video frames and has an output providing the second input to the encoder;
a processor memory connected to the statistical analysis processor for storing code that is executable by the processor to determine the parameter data to enable the encoder to allocate bits, the code causing the processor to perform the following steps:
determine scene change frames in the video frames;
determine when a first scene change frame and a second scene change frame occur greater than a first threshold number of frames apart, and when so providing information for the encoder to encoding the first and second scene changes in a normal fashion;
determine that the first scene change frame and the second scene change frame occur less than the first threshold number of frames, and when so performing the following steps:
determine a complexity of a first scene (X 1 ), a second scene (X 2 ) and a third scene (X 3 ), wherein the X 1 , X 2 and X 3 are separated by the first and the second scene change frames; and
determine when an absolute difference between the complexity of X 1 and X 2 is greater than a first complexity threshold Xth1 and the absolute difference of the complexity of X 2 and X 3 is less than a second complexity threshold Xth2, and when so encoding the first scene change frame as a scene change I frame, but picking a quantization parameter (QP) based on a complexity that is blended from the complexity of X 2 and X 3 .
7. The apparatus of claim 6 , wherein the memory stores code to enable the statistical analysis processor to perform the further step of:
determining when an absolute difference between the complexity of X 1 and X 2 is greater than the first complexity threshold Xth1 and the absolute difference of the complexity of X 2 and X 3 is greater than the second complexity threshold Xth1, and when so encoding the first scene change frame and the second scene change frame as a scene change I frame.
8. The apparatus of claim 7 , wherein the memory stores code to enable the statistical analysis processor to perform the further step of:
determining when an absolute difference between the complexity of X 1 and X 2 is less than the second complexity threshold Xth2 and the absolute difference of the complexity of X 2 and X 3 is less than the second complexity threshold Xth2, and when so ignoring the first scene change frame and encoding the second scene change frame as a scene change I frame.