US-12621503-B2 - Method of processing digital video data and image capturing device

Abstract

A method of processing digital video data comprises continuously capturing digital video data representing image frames. While capturing the digital video data, the digital video data is encoded into a sequence of encoded image frames, the sequence comprising key frames and delta frames, and storing the sequence of encoded image frames. It is then determined that the stored sequence of encoded image frames is to be entropy coded and, as a consequence, entropy coding the sequence of encoded image frames into an entropy coded sequence of image frames and storing the entropy coded sequence of image frames.

Inventors

• Axel Keskikangas
• Viktor Edpalm

Assignees

• AXIS AB

Dates

Publication Date

20260505

Application Date

20240605

Priority Date

20230614

Claims (18)

1. 1 . A method, performed in an image capturing device, of processing digital video data, the method comprising: continuously capturing digital video data representing image frames; while capturing the digital video data, encoding the digital video data into a sequence of encoded image frames, the sequence comprising key frames and delta frames, and storing the sequence of encoded image frames; determining that the stored sequence of encoded image frames is to be entropy coded and, as a consequence, entropy coding the sequence of encoded image frames into an entropy coded sequence of image frames and storing the entropy coded sequence of image frames, wherein the determining that the stored sequence of encoded image frames is to be entropy coded is based on receiving a triggering signal, and wherein the reception of the triggering signal comprises receiving a signal that is indicating that the image capturing device is operating under external power.
2. 2 . The method according to claim 1 , wherein the reception of the triggering signal comprises any of: receiving a signal via a user interface in the image capturing device; receiving information that is indicating that the image capturing device is operating according to a power supply budget that currently allows entropy coding.
3. 3 . The method according to claim 2 , wherein: the capturing of the digital video data is initiated as a consequence of receiving an initiation signal.
4. 4 . The method according to claim 1 , wherein the entropy coding of the sequence of encoded image frames into an entropy coded sequence of image frames and the storing of the entropy coded sequence of image frames is performed by the image capturing device.
5. 5 . The method according to claim 4 , wherein: the capturing of the digital video data is initiated as a consequence of receiving an initiation signal.
6. 6 . The method according to claim 1 , comprising providing the sequence of encoded image frames from the image capturing device to a processing system and wherein the entropy coding of the sequence of encoded image frames into an entropy coded sequence of image frames and the storing of the entropy coded sequence of image frames is performed by the processing system.
7. 7 . The method according to claim 6 , wherein: the capturing of the digital video data is initiated as a consequence of receiving an initiation signal.
8. 8 . The method according to claim 1 , wherein: the capturing of the digital video data is initiated as a consequence of receiving an initiation signal.
9. 9 . The method according to claim 8 , performed in an image capturing device, wherein the reception of the initiation signal comprises any of: receiving a signal via an input/output circuitry in the image capturing device; receiving information that is indicating that the image capturing device is operating according to a power supply budget that currently disallows entropy coding; receiving a signal that is indicating that the image capturing device is operating under internal battery power; receiving a signal that is indicating a detected event in audio content recorded by the image capturing device; receiving a signal that is indicating a changed connection status of a positioning circuitry that determines the location of the image capturing device; or receiving a signal that is indicating a changed connection status of a wireless communication circuitry of the image capturing device.
10. 10 . The method according to claim 1 , wherein the encoding of the digital video data into a sequence of encoded image frames is performed by an encoder operating according to any of: H.264 as specified by the International Telecommunication Union Telecommunication Standardization Sector (ITU-T); H.265 as specified by the ITU-T; Advanced Video Coding, AVC, as specified by the International Organization for Standardization and the International Electrotechnical Commission joint technical committee (ISO/IEC JTC 1); High Efficiency Video Coding, HEVC, as specified by the ISO/IEC JTC 1; or AOMedia Video 1, AV1, as specified by the Alliance for Open Media (AOMedia).
11. 11 . An image capturing device comprising circuitry configured to: continuously capture digital video data representing image frames; while capturing the digital video data, encode the digital video data into a sequence of encoded image frames, the sequence comprising key frames and delta frames, and store the sequence of encoded image frames; determine that the stored sequence of encoded image frames is to be entropy coded and, as a consequence, entropy code the sequence of encoded image frames into an entropy coded sequence of image frames and store the entropy coded sequence of image frames, wherein the circuitry is configured such that: the determining that the stored sequence of encoded image frames is to be entropy coded is based on receiving a triggering signal that is indicating that the image capturing device is operating under external power.
12. 12 . The image capturing device according to claim 11 , wherein the circuitry is configured such that: the entropy coding of the sequence of encoded image frames into an entropy coded sequence of image frames and the storing of the entropy coded sequence of image frames is performed by the image capturing device.
13. 13 . The image capturing device according to claim 11 , wherein the circuitry is configured such that: the capturing of the digital video data is initiated as a consequence of receiving an initiation signal.
14. 14 . The image capturing device according to claim 13 , wherein the circuitry is configured such that: the reception of the initiation signal comprises any of: receiving a signal via an input/output circuitry in the image capturing device; receiving information that is indicating that the image capturing device is operating according to a power supply budget that currently disallows entropy coding; receiving a signal that is indicating that the image capturing device is operating under internal battery power; receiving a signal that is indicating a detected event in audio content recorded by the image capturing device; receiving a signal that is indicating a changed connection status of a positioning circuitry that determines the location of the image capturing device; receiving a signal that is indicating a changed connection status of a wireless communication circuitry of the image capturing device.
15. 15 . The image capturing device according to claim 11 , wherein the circuitry is configured such that: the encoding of the digital video data into a sequence of encoded image frames is performed by an encoder operating according to any of: H.264 as specified by the International Telecommunication Union Telecommunication Standardization Sector (ITU-T); H.265 as specified by the ITU-T; Advanced Video Coding, AVC, as specified by the International Organization for Standardization and the International Electrotechnical Commission joint technical committee (ISO/IEC JTC 1); High Efficiency Video Coding, HEVC, as specified by the ISO/IEC JTC 1, or AOMedia Video 1, AV1, as specified by the Alliance for Open Media (AOMedia).
16. 16 . The image capturing device according to claim 11 , whereby said image capturing device comprises a body worn camera (BWC).
17. 17 . The image capturing device according to claim 12 , wherein the circuitry is configured such that: the capturing of the digital video data is initiated as a consequence of receiving an initiation signal.
18. 18 . The image capturing device according to claim 17 , wherein the circuitry is configured such that: the reception of the initiation signal comprises any of: receiving a signal via an input/output circuitry in the image capturing device; receiving information that is indicating that the image capturing device is operating according to a power supply budget that currently disallows entropy coding; receiving a signal that is indicating that the image capturing device is operating under internal battery power; receiving a signal that is indicating a detected event in audio content recorded by the image capturing device; receiving a signal that is indicating a changed connection status of a positioning circuitry that determines the location of the image capturing device; receiving a signal that is indicating a changed connection status of a wireless communication circuitry of the image capturing device.

Description

FIELD OF INVENTION The present disclosure relates to processing of digital video data representing a captured sequence of image frames and an image capturing device comprising circuitry configured to perform such processing. TECHNICAL BACKGROUND A trend in the development of image capturing devices capable of capturing video data, i.e. cameras, is a demand for high image resolution and high image quality in terms of, e.g., dynamical range and high quality of colour representation while at the same time minimizing the amount of data required to represent such high image quality. In order to meet such demands, various algorithms have been developed during the last decades, each generation of algorithms being more complex than the previous generation. Consequently, there has been a continuous increase in the demand for higher and higher processing power of the cameras. The development of image capturing devices is therefore faced with the inevitable problem of compromising between high quality and the amount of energy available for powering the cameras, noting that most types of cameras are battery powered. SUMMARY It is of interest to provide a method that overcomes drawbacks as discussed above. This and other objects are achieved in a first aspect by providing a method having the features of the appended independent claim. Preferred embodiments are defined in the appended dependent claims. Hence, according to a first aspect there is provided a method of processing digital video data. The method comprises continuously capturing digital video data representing image frames. While capturing the digital video data, the digital video data is encoded into a sequence of encoded image frames, the sequence comprising key frames and delta frames, and storing the sequence of encoded image frames. It is then determined that the stored sequence of encoded image frames is to be entropy coded and, as a consequence, entropy coding the sequence of encoded image frames into an entropy coded sequence of image frames and storing the entropy coded sequence of image frames. The encoding of the digital video data into a sequence of encoded image frames may be performed by an encoder operating according to any of H.264 as specified by the International Telecommunication Union Telecommunication Standardization Sector (ITU-T), H.265 as specified by the ITU-T, Advanced Video Coding (AVC) as specified by the International Organization for Standardization and the International Electrotechnical Commission joint technical committee (ISO/IEC JTC 1) High Efficiency Video Coding (HEVC) as specified by the ISO/IEC JTC 1 and AOMedia Video 1 (AV1), as specified by the Alliance for Open Media (AOMedia). By introducing the step of determining that the stored sequence of encoded image frames is to be entropy coded, the generation of the sequence of encoded image frames and the entropy coding, i.e. compression, of the sequence of encoded image frames can be separated in time. Such time can be minutes, hours or even days. This allows a device in which the method is performed to reduce the use of processing power while operating under a restricted power budget. Such a restricted power budge may for example be used while running on battery power or when the battery power is below a threshold, e.g. less than 20%. The reduction of power usage originates from that the present method makes it possible to postpone power demanding entropy encoding to a later point in time. For example, entropy encoding can be by postponing until the device is under no power usage restriction any more, e.g. when being powered by an external power source. Hence, introducing the postponement of the entropy encoding facilitates to maximize the time of operation for the capturing of video data and the encoding of the captured video data into a sequence of encoded image frames. This since battery power may be saved by not performing the entropy encoding when the device is operating under the restricted power budget. The determining that the stored sequence of encoded image frames is to be entropy coded may comprise receiving a triggering signal. The reception of the triggering signal may comprise receiving a signal via a user interface in an image capturing device executing the method. Alternatively, or in combination, the reception of the triggering signal may comprise, receiving information that is indicating that the image capturing device executing the method is operating according to a power supply budget that currently allows entropy coding. Alternatively, or in combination, the reception of the triggering signal may comprise receiving a signal that is indicating that the image capturing device executing the method is operating under external power. Hence, the triggering of performing the entropy coding of the stored sequence of encoded image frames may be an action taken by a user via a user interface as well as a more automatic action of, e.g., detecting that the device h