Ittiam Systems (p) Ltd.

Arvind Raman

Murali Babu Muthukrishnan

Sriram Sethuraman

Bhavani Gopalakrishna Rao

Sankaranarayanan Parameswaran

Dileep Kumar Tamia

Manish Singhal

Omkiran Sharma

Ashwini Kumar

Malavika Bhaskaranand

A method/system of transcoding an MPEG 2/4 bit stream into an H.264 format, handles an input MPEG 2/4 bit stream in a decoder, and identifies certain data in the input bit stream for reuse in the H.264 format; and, reuses the identified data in a re-encoder with assistance from a mapping module in transcoding by converting the input bit stream into an output H.264 format. The identified data includes information at a macrolevel and information at a picture level. The information at the macrolevel might comprise additional stages incorporated in the re-encoder module including a Mapping Process stage, a Sub Pixel Refinement stage, a Mode Selection stage to choose from Intra, Inter or Skip modes, followed by the standard H.264 encoding loop and the Entropy Coding Block. The information at the picture level might include; a) average quantizer of frame, and, b) total bits per frame.

Technique for transcoding MPEG-2/MPEG-4 bitstream to H.264 bitstream

A motion estimation algorithm finds the best match for a given block or macroblock so that the resulting error signal has very low energy level which is computed, for e.g., by the SAD method. The motion estimation algorithm also provides for an optional sub-pixel level estimation and an inter4v search, and allows for restricting the number of searches for a Frame-frame ME (motion estimation) using Top-Top and Bottom-Bottom field MEs. The algorithm provides for a selective early exit and enables selecting a suitable search area with N candidate points (4 to 8) for starting the search. The search is conducted progressively till a minimum error signal (low energy level signal) is reached. The candidate points for search may be in a diamond shaped configuration, and there may be a plurality of successive diamond configurations, the number of which is configurable. The invention has application in MPEG-4 and H.264 standards.

Fast motion-estimation scheme

A method for achieving bit rate controlled encoding, e.g., constant bit rate, uses a bit rate control model based on bits allocated per macroblock and based on error in estimating bits consumed in an encoding process in a macroblock. The method computes bits consumed per macroblock as a function of the formed bit rate control model, and allocates bits for the macroblock. To this end, a quadratic (second order) equation is used for the model, which equation might default into a first order equation requiring fewer computations, in the event that no second order solutions exist. In one form, the bit rate control model computes the bit rate to satisfy video buffer verifier (VBV) compliance in accordance with MPEG requirements. The bit rate control model makes allowances for the type of macroblock, i.e., inter, intra or bidirectional, and provides for any frame-skips.

Model based bit rate control for a macroblock encoder

Efficient techniques are provided to detect and correct channel errors found in an encoded video signal. In one example embodiment, header and global information in a video frame is analyzed to detect channel errors in the video frame. The video frame is then corrected for detected channel errors by isolating the detected channel errors to a few macroblocks in the video frame to reduce data loss and improve video quality.

System, method, and apparatus for error recovery in coded video signals

Efficient techniques are provided to detect and correct channel errors found in an encoded video signal. In one example embodiment, header information in a video frame is analyzed to detect channel errors in the video frame. The video frame is then corrected for detected channel errors by isolating the detected channel errors to a few macroblocks in the video frame to reduce data loss and improve video quality.

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Karnataka, India

Arvind Raman