PRESERVING IMAGE QUALITY IN TEMPORALLY COMPRESSED VIDEO STREAMS

摘要

When a temporally compressed video stream is decoded and subsequently re-encoded, quality is typically lost. The quality loss may be mitigated using information about how the source video stream was encoded during the re-encoding process. According to some aspects of the disclosure, this mitigation of quality loss can be facilitated by decoders that output such information and encoders that receive such information. These decoders and encoders may be separate devices. The functionality of these decoders and encoders may also be combined in a single device, such as a transcoding device. An example of the information that may be used during re-encoding is whether each portion of the original stream was intra-coded or non-intra-coded.

主权项

1. A method comprising:
receiving, at a device, a video stream in a first format that uses temporal compression; identifying, at the device, a set of regions that are each intra-coded in the video stream in the first format; transcoding, at the device, the video stream in the first format to a second format, wherein the identified set of regions is used during the transcoding to select each of the regions in the set for intra-coding in the second format; and outputting, from the device, the video stream in the second format, wherein each region in the identified set of regions corresponds to an intra-coded region of the video stream in the second format; wherein the regions that make up the set of regions are identified based at least in part on a quality target for the video stream in the second format.