Frame-rate conversion in a distributed computing system

摘要

Described herein are, among other things, distributed processing methods and systems for frame rate conversion. In an embodiment, a transcoding management machine manages a distributed transcoding process, creating a plurality of video segments and assigning the video segments across a set of distributed transcoding resources for frame rate conversion. The management machine typically sends a given segment to a given transcoding resource along with instructions to convert the frame rate to a specified output frame rate. In addition, the management machine can send certain transcoding assistance information that preferably facilitates the frame rate change process and helps the transcoding resource to create a more accurate output segment. Hence, in some embodiments, each transcoding resource can perform its transcode job independently, but with reference to the input segment it is responsible for transcoding and the assistance information provided by the management machine.

主权项

1. A system for frame-rate conversion in a distributed computing system, comprising:
each of a management machine and a first and a second transcoding resource machines comprising at least one microprocessor that is coupled to memory storing code executable by the at least one microprocessor to operate the given machine as described herein; the management machine storing code in memory executable to send first and second segments to the first and second transcoding resource machines, respectively, wherein each of the first and second segments represent portions of a video that are distinct from one another; wherein the management machine further stores code in memory executable to send an instruction to the first transcoding resource machine to convert a frame rate of the portion of the video represented by the first segment to an output frame rate, and to send an instruction to the second transcoding resource machine to convert a frame rate of the portion of the video represented by the second segment to the output frame rate; wherein the management machine further stores code in memory executable to send to the first transcoding resource machine:
(i) a first time stamp that represents a reference point in the video;(ii) a second time stamp that is associated with the initial frame of a segment of the video immediately following the first segment; wherein the first transcoding resource machine stores code in memory executable to create an output segment at the output frame rate from the first segment, the output segment having an output frame period (OFP) that corresponds to the output frame rate specified in the instruction from the management machine, having an output frame number (OFN) for the initial frame in the output segment, and having a start-of-segment offset time (t2); wherein the value of OFN is determined by any of the first transcoding resource machine and the management machine, upon execution of stored code, at least in part by evaluating a function that comprises dividing D by OFP to obtain a quotient and rounding the quotient, with D representing the time difference between the beginning of the first segment and the first time stamp; wherein the value of t2 is determined by the first transcoding machine, upon execution of stored code, at least in part by evaluating a function that comprises subtracting D from the product of multiplying OFN by OFP.