System and method for encoding video content using virtual intra-frames

Patent metadata

Field	Value
Publication number	US-9813732-B2
Application number	US-201314411324-A
Country	US
Kind code	B2
Filing date	Jun 26, 2013
Priority date	Jun 28, 2012
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

Systems and methods are provided for encoding raw image content encoded using one or more virtual intra-frames. In an exemplary method, a stream of video content may be encoded to generate compressed video data that includes an intra-frame and a plurality of corresponding inter-frames. The compressed video data may be stored within a buffer, and when the amount of data in the buffer exceeds a threshold value, a virtual intra-frame may be computed based on decoded inter-frame data. The virtual intra-frame may be output for storage in the buffer.

First claim

The invention claimed is:

1. A computer-implemented method, comprising:
receiving a stream of video content;
encoding, using a video codec, the video content stream to generate compressed video data, the compressed video data comprising an intra-frame and a plurality of corresponding inter-frames; and
storing the compressed video data within a buffer,
wherein the encoding comprises:
obtaining intra-frame data associated with the encoded intra-frame;
encoding, based on the intra-frame data, a portion of the video content stream to generate a corresponding one of the inter-frames;
determining whether an amount of compressed data stored in the buffer exceeds a first threshold value;
when the amount of compressed data in the buffer exceeds the first threshold value, decoding the last generated inter-frame in the buffer and computing a viral intra-frame based on the decoded inter-frame data, the virtual intra-frame representing an out of sequence intra-frame in a group-of-pictures; and
outputting the virtual intra-frame with the last generated inter-frame for storage in the buffer.

2. The method of claim 1 , wherein the encoding further comprises encoding a first portion of the video content stream to generate the intra-frame, the first portion preceding the portion of the video content stream associated with the inter-frame.

3. The method of claim 1 , wherein the encoding further comprises;
computing a group-of-pictures length associated with the compressed video data, when the amount of buffered data fails to exceed the first threshold value;
determining whether the computed group-of-pictures length exceeds a predetermined threshold length; and
encoding an additional portion of the video content stream to generate an additional inter-frame, when the computed group-of-pictures length does not exceed the predetermined threshold length.

4. The method of claim 3 , wherein:
the buffer comprises one or more previously-encoded groups of intra-frames and corresponding inter-frames; and
when the computed group-of-pictures length exceeds the predetermined threshold length, discarding the previously-encoded groups of intra-frames and corresponding inter-frames.

5. The method of claim 1 , wherein the encoding further comprises determining whether the amount of buffered data exceeds a second threshold value, the second threshold value being larger than the first threshold value.

6. The method of claim 5 , wherein the encoding further comprises maintaining the virtual intra-frame and discarding encoding video content preceding the virtual intra-frame, when the amount of buffered data exceeds the second threshold value.

7. The method of claim 1 , further comprising:
receiving information indicative of a triggering incident; and
generating, based on the received information, an instruction to transmit at least a portion of the buffered data to a recipient.

8. The method of claim 7 , wherein the triggering incident comprises at least one of a request for video content, an occurrence of a predetermined event within the received video stream, a receipt of predetermined data through an interface, or a detection of a predetermined event by a sensor.

9. The method of claim 7 , wherein generating the instruction further comprises:
determining whether the buffered data includes the intra-frame and the virtual intra-frame;
discarding the virtual intra-frame and maintaining the corresponding inter-frame, when the buffered data includes the intra-frame and the virtual intra-frame; and
generating the buffered data portion based on the intra-frame.

10. The method of claim 7 , further comprising:
determining whether the buffered data includes the virtual intra-frame and fails to include the intra-frame; and
generating the buffered data portion based on the virtual intra-frame, when the buffered data includes the virtual intra-frame and fails to include the intra-frame.

11. The method of claim 1 , further comprising:
receiving at least one frame of compressed video data; decoding the received frame;
determining whether the decoded frame corresponds to an intra-frame; and
storing at least the decoded frame in a data repository, when the decoded frame corresponds to an intra-frame.

12. The method of claim 11 , further comprising:
determining that the decoded frame corresponds to an inter-frame;
when the decoded frame is an inter-frame, computing a group-of-pictures length associated with the received data;
determining whether the computed group-of-pictures length exceeds a predetermined threshold length; and
storing at least the decoded inter-frame within the data repository, when the computer group-of-pictures length fails to exceed the predetermined threshold length.

13. The method of claim 12 , further comprising:
generating an additional intra-frame based on the decoded inter-frame data, when the computed group-of-pictures length exceeds the predetermined threshold length; and
storing at least the additional intra-frame within the data repository.

14. An apparatus, comprising:
a video codec configured to encode a stream of video content to generate compressed video data, the compressed video data comprising an intra-frame and a plurality of corresponding inter-frames; and
a storage device couple to the video codec unit and configured to store the compressed video data within a buffer,
wherein the video codec is further configured to:
obtain intra-frame data associated with the encoded intra-frame;
encode, based on the intra-frame data, a portion of the video content stream to generate a corresponding one of the inter-frames;
determine whether an amount of compressed data stored in the buffer exceeds a first threshold value;
when the amount of compressed data in the buffer exceeds the first threshold value, decode the last generated inter-frame in the buffer and compute a virtual intra-frame based on the decoded inter-frame data, the virtual intra-frame representing an out of sequence intra-frame in a group-of-pictures; and
provide the virtual intra-frame with the last generated intra-frame as output for storage in the buffer.

15. The apparatus of claim 14 , wherein the video codec is further configured to:
encode a first portion of the video content stream to generate the intra-frame, the first portion preceding the portion of the video content stream associated with the inter-frame.

16. The apparatus of claim 14 , wherein the video codec is further configured to:
compute a group-of-pictures length associated with the compressed video data, when the amount of buffered data fails to exceed the first threshold value;
determine whether the computed group-of-pictures length exceeds a predetermined threshold length; and
encode an additional portion of the video content stream to generate an additional inter-frame, when the computed group-of-pictures length fails to exceed the predetermined threshold length.

17. The apparatus of claim 16 , wherein:
the buffer comprises one or more previously-encoded groups of intra-frames and corresponding inter-frames; and
when the computed group-of-pictures length exceeds the predetermined threshold length, the video codec is further configured to discard the previously-encoded groups of inter-frames and corresponding inter-frames.

18. The apparatus of claim 14 , wherein the video codec is further configured to:
determine whether the amount of buffered data exceeds a second threshold value, the second threshold value being larger than the first threshold value.

19

Assignees

• Axis Ab

Inventors

• Lundberg Stefan

Classifications

• H04N21/23424

  involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement · CPC title

• H04N21/23439

  for generating different versions · CPC title

• H04N19/587

  involving temporal sub-sampling or interpolation, e.g. decimation or subsequent interpolation of pictures in a video sequence · CPC title

• H04N19/30 Primary

  using hierarchical techniques, e.g. scalability (H04N19/63 takes precedence) · CPC title

• H04N19/156

  Availability of hardware or computational resources, e.g. encoding based on power-saving criteria · CPC title