Video encoder bit estimator for macroblock encoding
View Patent ↗A video transmission system includes an encoder to receive video images, and encode them for transfer to a decoder. The video images include macroblocks having data that are encoded according to a prediction mode, such as inter-prediction or intra-prediction. A bit estimator for the encoded macroblock within the encoder estimates a size for the encoded macroblock and predicts whether it will be an illegal size. The bit estimator applies a bit estimation function using a number of header bits and a number of texture bits based on the prediction mode and transformed data of the macroblock.
1. A method for predicting an illegal macroblock within a video encoder, the method comprising:
deciding a prediction mode based on motion estimation and spatial prediction for a macroblock within a video image;
performing a transform on data and a specific compression level over the data within the macroblock from the prediction mode selected;
performing a bit estimation function to predict a size of the macroblock based on the prediction mode and the transformed data;
comparing the predicted size to a threshold; and
applying a special prediction mode to encode the macroblock to reduce the size of the encoded macroblock when the predicted size exceeds the threshold.
2. The method of claim 1 , wherein the performing the bit estimation function step includes estimating a number of header bits within the macroblock.
3. The method of claim 1 , wherein the performing the bit estimation function step includes estimating a number of texture bits within the macroblock.
4. The method of claim 1 , wherein the deciding step includes determining whether the macroblock is an inter-macroblock or intra-macroblock.
5. The method of claim 3 , wherein the estimating the number of texture bits step includes determining a prediction error for the macroblock.
6. The method of claim 3 , wherein the estimating the number of texture bits step includes determining a compression level for the macroblock.
7. The method of claim 1 , further comprising encoding the macroblock according to the prediction mode.