Method and transcoding proxy for transcoding a media stream that is delivered to an end-user device over a communications network

• US 8,782,165 B2
• Filed: 01/26/2011
• Issued: 07/15/2014
• Est. Priority Date: 01/26/2011
• Status: Active Grant

• Current Assignee: Openwave Mobility Inc. (Enea AB)
• Original Assignee: Openwave Mobility Inc. (Enea AB)
• Inventors: Fee, Paul, Wright, Stephen, Harrison, Declan
• Primary Examiner(s): Gee, Jason K.
• Assistant Examiner(s): LWIN, MAUNG T
• Application Number:
  US13/014,017
• Publication Number:
  US 20120191805A1
• Time in Patent Office: 1,266 Days
• Field of Search: 370/401
• US Class Current: 709/217
• CPC Class Codes: H04N 21/222 Secondary servers, e.g. proxy server, cable television Head-end provisioning of proxy services in data packet switching networks H04L67/56
• CPC Class Codes: H04N 21/2343 involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements video transcoding H04N19/40; media packet handling at the source H04L65/762
• CPC Class Codes: H04N 21/234309 by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4 or from Quicktime to Realvideo conversion of standards in analog television systems H04N7/01
• CPC Class Codes: H04N 21/234363 by altering the spatial resolution, e.g. for clients with a lower screen resolution
• CPC Class Codes: H04N 21/234381 by altering the temporal resolution, e.g. decreasing the frame rate by frame skipping
• CPC Class Codes: H04N 21/24 Monitoring of processes or resources, e.g. monitoring of server load, available bandwidth, upstream requests monitoring of server performance or load G06F11/34; arrangements for observation, testing or troubleshooting for broadcast or for distribution combined with broadcast H04H20/12
• CPC Class Codes: H04N 21/2402 Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/25808 Management of client data terminal profiles in network data switching protocols H04L67/303
• CPC Class Codes: H04N 21/26216 involving the channel capacity, e.g. network bandwidth admission control, resource allocation in open networks H04L12/5692; flow control in packet networks H04L47/10; establishing a schedule or organising the servicing of application requests taking into account QoS H04L67/61
• CPC Class Codes: H04N 21/64707 for transferring content from a first network to a second network, e.g. between IP and wireless
• CPC Class Codes: H04N 21/64738 Monitoring network characteristics, e.g. bandwidth, congestion level data switched network analysis H04L41/14; monitoring functioning in data switched networks H04L43/0817; flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/64746 Control signals issued by the network directed to the server or the client
• CPC Class Codes: H04N 21/64769 for rate control flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• CPC Class Codes: H04W 88/181 Transcoding devices; Rate adaptation devices

Abstract

Methods and transcoding proxies for transcoding media streams are described. In one embodiment, a method for transcoding a media stream that is delivered to an end-user device over a communications network involves selecting a transcoding technique for the media stream, transcoding a portion of the media stream using the selected transcoding technique, streaming the transcoded portion of the media stream to the end-user device, while the transcoded portion of the media stream is being streamed to the end-user device, detecting a change in a condition of the communications network, selecting a different transcoding technique in response to the change in the condition of the communications network, transcoding a subsequent portion of the media stream using the different transcoding technique, and streaming the transcoded subsequent portion of the media stream to the end-user device. Other embodiments are also described.

Claims

1. A method for transcoding a video stream that is delivered to an end-user device over a communications network, the method comprising:

selecting a transcoding technique for the video stream;

transcoding a portion of the video stream using the selected transcoding technique;

streaming the transcoded portion of the video stream to the end-user device;

while the transcoded portion of the video stream is being streamed to the end-user device, detecting a change in a condition of the communications network;

selecting a different transcoding technique in response to the change in the condition of the communications network;

transcoding a subsequent portion of the video stream using the different transcoding technique; and

streaming the transcoded subsequent portion of the video stream to the end-user device, wherein detecting the change in the condition of the communications network is based upon a calculation of a difference between a presentation timestamp of a video frame in the video stream and an elapsed time of the video frame, wherein the presentation timestamp indicates a correct time to display the video frame at the end-user device and the elapsed time is the time between when a transcoding proxy begins to transmit video frames of the video stream to the end-user device and when the end-user device fully receives the video frame.

2. The method of claim 1 further comprising:

receiving the portion of the video stream from a content source at the transcoding proxy; and

receiving the subsequent portion of the video stream from the content source at the transcoding proxy,

wherein transcoding the portion of the video stream using the selected transcoding technique comprises transcoding the portion of the video stream using the selected transcoding technique at the transcoding proxy, and wherein transcoding the subsequent portion of the video stream using the different transcoding technique comprises transcoding the subsequent portion of the video stream using the different transcoding technique at the transcoding proxy.

3. The method of claim 1, wherein the condition of the communications network comprises a bandwidth condition of the communications network.

4. The method of claim 3, wherein selecting the different transcoding technique in response to the change in the condition of the communications network comprises selecting the different transcoding technique that results in a transcoded video stream whose size is smaller than the original transcoded video stream if the bandwidth condition of the communications network indicates that the communications network becomes more congested.

5. The method of claim 3, wherein selecting the different transcoding technique in response to the change in the condition of the communications network comprises selecting the different transcoding technique that results in a transcoded video stream whose size is larger than the original transcoded video stream if the bandwidth condition of the communications network indicates that the communications network becomes less congested.

6. The method of claim 1, wherein selecting the transcoding technique for the video stream comprises establishing an encoder session with a unique session identifier for the video stream.

7. The method of claim 6, wherein selecting the transcoding technique for the video stream further comprises selecting a virtual encoder for the encoder session, and wherein transcoding the portion of the video stream using the selected transcoding technique comprises transcoding the portion of the video stream using the virtual encoder.

8. The method of claim 7, wherein selecting the different transcoding technique in response to the change in the condition of the communications network comprises selecting a different virtual encoder for the encoder session, and wherein transcoding the subsequent portion of the video stream using the different transcoding technique comprises transcoding the subsequent portion of the video stream using the different virtual encoder.

9. The method of claim 1 wherein detecting the change in a condition of the network is based upon a comparison of the difference and one or more threshold values.

10. The method of claim 9 wherein, if the difference is less than or at a threshold value, selecting the different transcoding technique so that the subsequent portion of the video stream is transcoded at a higher level of compression than was the portion of the video stream.

11. The method of claim 9 wherein, if the difference is greater than or at a threshold value, selecting the different transcoding technique so that the subsequent portion of the video stream is transcoded at a lower level of compression than was the portion of the video stream.

12. The method of claim 1 further comprising calculating the difference between the presentation timestamp and the elapsed time.

13. A transcoding proxy for transcoding a video stream that is delivered to an end-user device over a communications network, the transcoding proxy comprising:

a non-transitory computer readable medium configured to store executable program instructions, which, when executed by an apparatus, cause the apparatus to implement;

a transcoding server configured to select a transcoding technique for the video stream, to transcode a portion of the video stream using the selected transcoding technique, and to stream the transcoded portion of the video stream to the end-user device;

a transcoding router configured to detect a change in a condition of the communications network while the transcoded portion of the video stream is being streamed to the end-user device,

wherein the transcoding server is further configured to select a different transcoding technique in response to the change in the condition of the communications network, to transcode a subsequent portion of the video stream using the different transcoding technique, and to stream the transcoded subsequent portion of the video stream to the end-user device,

wherein the change in the condition of the communications network is detected based upon a calculation of a difference between a presentation timestamp of a video frame in the video stream and an elapsed time of the video frame, wherein the presentation timestamp indicates a correct time to display the video frame at the end-user device and the elapsed time is the time between when the transcoding proxy begins to transmit video frames of the video stream to the end-user device and when the end-user device fully receives the video frame.

14. The transcoding proxy of claim 13, wherein the condition of the communications network comprises a bandwidth condition of the communications network.

15. The transcoding proxy of claim 14, wherein the transcoding server is further configured to select the different transcoding technique that results in a transcoded video stream whose size is smaller than the original transcoded video stream if the bandwidth condition of the communications network indicates that the communications network becomes more congested.

16. The transcoding proxy of claim 14, wherein the transcoding server is further configured to select the different transcoding technique that results in a transcoded video stream whose size is larger than the original transcoded video stream if the bandwidth condition of the communications network indicates that the communications network becomes less congested.

17. The transcoding proxy of claim 13, wherein the change in the condition of the communications network is communicated from the communications network as feedback information.

18. The transcoding proxy of claim 13, wherein the transcoding server is further configured to establish an encoder session with a unique session identifier for the video stream, to select a virtual encoder for the encoder session, and to transcode the portion of the video stream using the virtual encoder.

19. The transcoding proxy of claim 18, wherein the transcoding server is further configured to select a different virtual encoder for the encoder session and to transcode the subsequent portion of the video stream using the different virtual encoder.

20. The transcoding proxy of claim 13 wherein detecting the change in a condition of the network is based upon a comparison of the difference and one or more threshold values.

21. The transcoding proxy of claim 20 wherein, if the difference is less than a threshold value, the transcoding server is further configured to select the different transcoding technique so that the subsequent portion of the video stream is transcoded at a higher level of compression than was the portion of the video stream.

22. The transcoding proxy of claim 20 wherein, if the difference is greater than a threshold value, the transcoding server is further configured to select the different transcoding technique so that the subsequent portion of the video stream is transcoded at a lower level of compression than was the portion of the video stream.

23. A non-transitory computer readable medium configured to store executable program instructions, which, when executed by an apparatus, cause the apparatus to perform the steps of:

selecting a transcoding technique for a video stream;

transcoding a portion of the video stream using the selected transcoding technique;

streaming the transcoded portion of the video stream to an end-user device;

while the transcoded portion of the video stream is being streamed to the end-user device, detecting a change in a condition of the communications network;

selecting a different transcoding technique in response to the change in the condition of the communications network;

transcoding a subsequent portion of the video stream using the different transcoding technique; and

streaming the transcoded subsequent portion of the video stream to the end-user device, wherein detecting the change in the condition of the communications network is based upon a calculation of a difference between a presentation timestamp of a video frame in the video stream and an elapsed time of the video frame, wherein the presentation timestamp indicates a correct time to display the video frame at the end-user device and the elapsed time is the time between when the apparatus begins to transmit video frames of the video stream to the end-user device and when the end-user device fully receives the video frame.