Video transcoding with dynamically modifiable spatial resolution
AssigneeMicrosoft Technology Licensing, LLC
InventorsThomas W. Holcomb, Chih-Lung B. Lin
Life of this patent
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Abstract
An apparatus and method are disclosed for transcoding a compressed video stream. In one embodiment, a compressed video stream is decoded. A spatial resolution of the decoded video stream can then be dynamically modified. The video stream with the modified spatial resolution can be re-encoded and transmitted over a network for display on a client device. The spatial resolution can be dynamically modified based on a variety of techniques. For example, a current bitrate and quantization parameters associated with the frames can be used to determine the spatial resolution. Alternatively, the spatial and/or temporal complexity can be used to modify spatial resolution.
Claims14
A method for transcoding a compressed video stream, comprising:
- decoding the compressed video stream;
- monitoring a network bit rate over which the video stream is to be transmitted;
- dynamically modifying a spatial resolution of the decoded video stream, wherein the spatial resolution relates to a number of independent pixel values associated with a group of pictures comprising a plurality of individual pictures of the video stream, wherein dynamically modifying includes:
- receiving the group of pictures,
- determining an average quantization parameter for the group of pictures, wherein the average quantization parameter is associated with a number of inter-coded pictures and a number of intra-coded picture bits,
- calculating a spatial complexity parameter and a temporal complexity parameter for the group of pictures, the spatial complexity parameter representative of a number of details in one of the group of pictures, and
- using the spatial complexity, temporal complexity, and average quantization parameters and the monitored bit rate to perform the modifying of the spatial resolution at a boundary of the group of pictures;
- encoding the video stream at the modified spatial resolution for the group of pictures;
- and
- transmitting the encoded video stream at the modified spatial resolution for display while the compressed video stream is being received.
An apparatus for transcoding a compressed video stream, comprising:
- a decoder for decoding a compressed video stream, the decoded video stream including a group of pictures;
- an encoder with dynamic spatial resolution decision logic for re-encoding the video stream received from the decoder, wherein the encoder determines an average quantization parameter for the group of pictures, determines a spatial complexity parameter and a temporal complexity parameter for the group of pictures, and receives a bit rate of a network, the spatial complexity parameter being associated with details in one of the group of pictures, the average quantization parameter being associated with inter-coded picture information and intra-coded picture information;
- a frame resizer positioned between the decoder and the encoder and responsive to control signals from the encoder for dynamically modifying a frame size of the decoded video stream at a boundary of the group of pictures and providing a resized decoded video stream with the modified frame size to the encoder, wherein modifying the frame size includes using the determined average quantization, spatial complexity, and temporal complexity parameters for the group of pictures in combination with the bit rate of the network.
A method for transcoding a compressed video stream, comprising:
- receiving a video stream;
- monitoring a bit rate of a network connection through which the video stream is being transmitted;
- partitioning a group of pictures from the video stream;
- determining an average quantization parameter for the group of pictures, wherein the average quantization parameter is associated with a number of inter-coded pictures within the group and a number of intra-coded picture bits per picture;
- calculating a spatial complexity parameter and a temporal complexity parameter for the group of pictures, the spatial complexity parameter representative of details in one of the group of pictures;
- resizing frames of the video stream at a boundary of the group of pictures based on the average quantization, spatial complexity, and temporal complexity parameters and the bitrate of the network connection;
- encoding the video stream with the resized frames;
- and
- transmitting the encoded video stream over a network for display on a client computer coupled to the network.
Dependencies are inferred from the claim text.