# US 2014/0153909 A1 · Audio and video management for parallel transcoding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153909 A1 - Document ID: US20140153909A1 - Status: Published application - Kind: A1 - Application number: 14/041,024 - Filed: 2013-09-30 - Published: 2014-06-05 - Earliest claimed: 2012-12-03 - Assignees: Avago Technologies General IP (Singapore) Pte. Ltd. - Applicants: Broadcom Corporation - Inventors: Alexander Garland MacInnis; Hongtao Zhu; Jason William Herrick; Brian Francis Schoner; Junlin Li - Web page: https://patentgrep.com/patent/US20140153909A1 ## CPC - H04N 9/80: Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback - H04N 5/91: Television signal processing therefor - H04N 9/7921: {for more than one processing mode} - H04N 19/40: using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream - H04N 19/436: using parallelised computational arrangements - H04N 21/242: Synchronisation processes, e.g. processing of PCR [Programme Clock References] {(arrangements for synchronising broadcast or distribution via plural systems in broadcast distribution systems H04H20/18)} - H04N 9/8205: {involving the multiplexing of an additional signal and the colour video signal} - H04N 21/8456: {by decomposing the content in the time domain, e.g. in time segments} - H04N 21/8547: involving timestamps for synchronizing content - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Disclosed are various embodiments directed to transcoding a bit stream comprising audio and video frames that contains discontinuities. The video and/or audio portion of the bit stream may be divided into segments, where some of the segments are transcoded in parallel using a plurality of transcoder devices. In some embodiments, a discontinuity is detected in the bit stream before encoding, where the discontinuity is associated with a shift in a set of time stamps associated with the bit stream. A magnitude of the discontinuity is determined. The transcoding system aligns at least a portion of the audio frames to the series of video frames according to at least the discontinuity and the magnitude of the discontinuity. In other embodiments, the discontinuity is detected after encoding by analyzing time stamps that have been established during the transcoding process. ## Claims ### Claim 1 A system, comprising: a memory for storing a media file, the media file comprising a video stream and an audio stream, the video stream comprising a series of pictures, at least a portion of the series of pictures being associated with original video time stamps, the audio stream comprising a series of audio frames, at least a portion of the series of audio frames being associated with original audio time stamps; a transcode manager configured to divide the video stream into input a plurality of segments that comprises respective subsets of the series of pictures, the transcode manager being further configured to assign video time stamps to at least a portion of the series of pictures, the transcode manager being further configured to assign audio time stamps to at least a portion of the series of audio frames; a plurality of video transcoder devices configured to transcode the input segments in parallel to generate corresponding output segments; an audio transcoder device configured to transcode at least a portion of the audio stream to generate a transcoded audio stream; and a multiplexer configured to determine a discontinuity in the media file based at least upon the video time stamps and the original video time stamps or based at least upon the audio time stamps and the original audio time stamps. ### Claim 2 (depends on 1) The system of claim 1, wherein the multiplexer is configured to aggregate the output segments and the transcoded audio stream to generate a transcoded media file. ### Claim 3 (depends on 1) The system of claim 1, wherein the multiplexer is configured to align at least a portion of the transcoded audio stream by shifting at least one audio time stamp among the audio time stamps according to an offset. ### Claim 4 (depends on 1) The system of claim 1, wherein the video time stamps are assigned based at least upon a time base, wherein the audio time stamps are assigned based at least upon the time base. ### Claim 5 (depends on 1) The system of claim 1, wherein the video time stamps, the original video time stamps, the audio time stamps, and the original audio time stamps specify respective presentation times. ### Claim 6 (depends on 1) The system of claim 1, wherein the audio transcoder device comprises a single audio transcoder device to serially process the audio stream. ### Claim 7 A method comprising: accessing a media file, the media file comprising a video stream and an audio stream, the video stream being associated with a set of original video time stamps, the audio stream being associated with a set of original audio time stamps; assigning at least a portion of a plurality of pictures in the video stream respective video time stamps based at least upon a time base; assigning at least a portion of a plurality of audio frames in the audio stream respective audio time stamps based at least upon the time base; dividing the video stream into a plurality of video segments; transcoding, using a plurality of video transcoder devices, at least a portion of the plurality of video segments in parallel to generate a transcoded video stream; transcoding the audio stream to generate a transcoded audio stream; and aligning the transcoded audio stream to the transcoded video stream based at least upon the original video time stamps and the video time stamps or based at least upon the original audio time stamps and the audio time stamps. ### Claim 8 (depends on 7) The method of claim 7, wherein the original video time stamps and the original audio time stamps specify respective presentation times. ### Claim 9 (depends on 8) The method of claim 8, further comprising: determining a video difference value between an original video time stamp and a video time stamp to generate a set of video difference values; and detecting a point of video discontinuity based at least upon a change within the set of video difference values. ### Claim 10 (depends on 7) The method of claim 7, further comprising: aligning the transcoded audio stream to the transcoded video stream in response to detecting a point of video discontinuity; and determining a misaligned audio frame in the audio stream, wherein aligning comprises removing the misaligned audio frame. ### Claim 11 (depends on 7) The method of claim 7, further comprising in response to determining the discontinuity, adjusting at least a portion of the audio time stamps to shift the transcoded audio stream. ### Claim 12 (depends on 11) The method of claim 11, further comprising dividing the audio stream into a plurality of audio segments, wherein transcoding the audio stream comprises transcoding at least a portion of the plurality of audio segments in parallel using a plurality of audio transcoder devices. ### Claim 13 A system, comprising: a transcode manager configured to: access a bit stream of a media file from a memory, the bit stream comprising a series of video frames and a series of audio frames; detect a discontinuity in the bit stream, the discontinuity being associated with a shift within a plurality of time stamps; determine a magnitude of the discontinuity; facilitate an alignment of at least a portion of the series of audio frames to the series of video frames according to at least the discontinuity and the magnitude of the discontinuity; and divide the series of video frames into a plurality of video segments, wherein the plurality of video transcoder devices is configured to transcode at least a portion of the plurality of video segments in parallel. ### Claim 14 (depends on 13) The system of claim 13, wherein the system further comprises at least one audio transcoder device configured to: receive a signal from the transcode manager; and in response to receiving the signal, align the portion of the series of audio frames by dropping an audio frame among the portion of the series of audio frames. ### Claim 15 (depends on 13) The system of claim 13, wherein the transcode manager is configured to detect the discontinuity according to a difference between an expected Program Reference Clock (PCR) value and an actual PCR value. ### Claim 16 (depends on 13) The system of claim 13, wherein the audio frames in the series of audio frames are associated with an audio frame interval, wherein the transcode manager is configured to facilitate the alignment of the portion of the series of audio frames by inserting an offset in the series of audio frames, the offset being unequal to the audio frame interval. ### Claim 17 (depends on 13) The system of claim 13, wherein the transcode manager is configured to facilitate the alignment of the portion of the audio frames by assigning presentation time stamps to at least a portion of the portion of the series of audio frames. ### Claim 18 (depends on 13) The system of claim 13, wherein the system comprises a multiplexer configured to align the portion of the series of audio frames. ### Claim 19 (depends on 13) The system of claim 13, wherein the plurality of time stamps comprises a set of Program Reference Clock (PCR) values included in the bit stream. ### Claim 20 (depends on 19) The system of claim 19, wherein the transcode manager is further configured to maintain an internal time base according to the set of PCR values, the internal time base being a System Time Clock (STC) that uses at least one of an oscillator or a counter.