High-performance video transcoding method

A method for generating a second compressed video stream having a second resolution, from a first compressed video stream having a first resolution encoded using an encoding method, said method comprising:

• separating luma transform data and chroma transform data for a frame from said first compressed video stream;
• applying a first reconstructing operation in a transform domain to said luma transform data to form reconstructed luma transform data;
• obtaining chroma data by inverse transforming said chroma transform data;
• applying, if a trigger condition is met, said first reconstructing operation to said chroma data to form reconstructed transform domain chroma data;
• applying, if said trigger condition is not met, a second reconstructing operation to said chroma data to form reconstructed chroma data;
• and
• generating said second compressed video stream by scaling and encoding said reconstructed luma transform data and said reconstructed chroma data using said encoding method.

A method of generating a scaled version of compressed video stream from a compressed video stream encoded using an encoding method, said method comprising:

• separating the luma and chroma data from said compressed video stream;
• processing said luma data in the transform domain using transform domain motion compensation and transform domain scaling operations;
• processing, if a trigger condition is met, said chroma data in the transform domain using said transform domain motion compensation and transform domain scaling operations;
• processing, if said trigger condition is not met, said chroma data in the spatial domain using spatial motion compensation and spatial scaling operations;
• and
• combining said processed luma and chroma data to generate said scaled version of compressed video stream using said encoding method.

A method of generating a scaled version of video data from a compressed video stream encoded using an encoding method, said method comprising:

• processing luma data in the transform domain using transform domain motion compensation and transform domain scaling operations;
• processing, if a trigger condition is met, said chroma data in the transform domain using said transform domain motion compensation and transform domain scaling operations;
• and
• processing, if said trigger condition is not met, chroma data in the spatial domain using spatial motion compensation and spatial scaling operations.

An apparatus for generating a second compressed video stream having a second resolution, from a first compressed video stream having a first resolution encoded using an encoding method, said apparatus comprising:

• means for separating transform domain luma data and spatial domain chroma data for a frame from said first compressed video stream;
• means for applying a transform domain operation to said luma data to form reconstructed transform domain luma data;
• means for applying, if a trigger condition is met, said transform domain operation to the chroma data to form reconstructed transform domain chroma data;
• means for applying, if the trigger condition is not met, a spatial domain operation to said chroma data to form reconstructed spatial domain chroma data;
• and
• means for scaling said reconstructed transform domain luma data and said reconstructed spatial domain chroma data to generate said second compressed video stream using said encoding method.

An apparatus for generating a second compressed video stream having a second resolution, from a first compressed video stream having a first resolution encoded using an encoding method, said apparatus comprising:

• a memory for storing a program;
• a processor for executing the program, said program comprising:
• code for separating transform domain luma data and spatial domain chroma data for a frame from said first compressed video stream;
• code for applying a transform domain operation to said luma data to form reconstructed transform domain luma data;
• code for applying, if a trigger condition is met, said transform domain operation to said chroma data to form reconstructed transform domain chroma data;
• code for applying, if the trigger condition is not met, a spatial domain operation to said chroma data to form reconstructed spatial domain chroma data;
• and
• code for scaling said reconstructed transform domain luma data and said reconstructed spatial domain chroma data to generate said second compressed video stream using the encoding method.

A computer program product including a non-transient computer readable storage medium having recorded thereof a computer program for directing a processor to execute a method for generating a second compressed video stream having a second resolution, from a first compressed video stream having a first resolution encoded using an encoding method, said program comprising:

• code for separating transform domain luma data and spatial domain chroma data for a frame from said first compressed video stream;
• code for applying a transform domain operation to said luma data to form reconstructed transform domain luma data;
• code for applying, if a trigger condition is met, said transform domain operation to said chroma data to form reconstructed transform domain chroma data;
• code for applying, if the trigger condition is not met, a spatial domain operation to said chroma data to form reconstructed spatial domain chroma data;
• and
• code for scaling said reconstructed transform domain luma data and said reconstructed spatial domain chroma data to generate said second compressed video stream using said encoding method.