# US 2019/0174177 A1 · Channel Change Method and Apparatus

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- Number: US 2019/0174177 A1
- Document ID: US20190174177A1
- Status: Published application
- Kind: A1
- Application number: 16/270,492
- Filed: 2019-02-07
- Published: 2019-06-06
- Earliest claimed: 2016-08-09
- Assignees: Huawei Technologies Co., Ltd.
- Applicants: Huawei Technologies Co., Ltd.
- Inventors: Zimian LI; Qiulin CHEN
- Web page: https://patentgrep.com/patent/US20190174177A1

## CPC

- H04N 21/4384: {involving operations to reduce the access time, e.g. fast-tuning for reducing channel switching latency}
- H04L 65/61: for supporting one-way streaming services, e.g. Internet radio
- H04L 65/611: for multicast or broadcast (systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06)
- H04L 65/612: for unicast
- H04L 65/65: Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
- H04L 65/70: Media network packetisation
- H04N 19/177: the unit being a group of pictures [GOP]
- H04N 21/23439: {for generating different versions}
- H04N 21/26258: {for generating a list of items to be played back in a given order, e.g. playlist, or scheduling item distribution according to such list (retrieval of multimedia data based on playlists G06F16/40)}
- H04N 21/438: Interfacing the downstream path of the transmission network originating from a server, e.g. retrieving encoded video stream packets from an IP network
- H04N 21/44016: {involving splicing one content stream with another content stream, e.g. for substituting a video clip}
- H04N 21/6125: {involving transmission via Internet (transmission by internet of broadcast information H04H60/82)}
- H04N 21/6175: {involving transmission via Internet (broadcast-related systems characterised by the transmission system being the Internet H04H60/82)}
- H04N 21/637: Control signals issued by the client directed to the server or network components
- H04N 21/8455: {involving pointers to the content, e.g. pointers to the I-frames of the video stream}
- H04N 21/8456: {by decomposing the content in the time domain, e.g. in time segments}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Embodiments of the present disclosure disclose a channel change method and a related apparatus. The channel change method includes: receiving a live stream of a first channel, where the live stream of the first channel includes N media file sets; separately encoding the live stream of the first channel in different coding manners, to generate both a main stream and a sub stream; and generating a playlist of the first channel according to channel information of the first channel, coding information of the main stream, and coding information of the sub stream. The playlist instructs the client to perform channel change according to the main stream and the sub stream in response to that a client sends a channel change instruction.

## Claims

### Claim 1

A channel change method, applied to an Over The Top (OTT) video service, wherein the method comprises:
receiving a live stream of a first channel, wherein the live stream of the first channel comprises N media file sets;
separately encoding the live stream of the first channel in different coding manners, to generate both a main stream and a sub stream, wherein the main stream comprises the N media file sets and main stream coding information, the sub stream comprises the N media file sets and sub stream coding information, wherein the main stream is used for live broadcast, and the sub stream is used for channel change; and
generating a playlist of the first channel according to channel information of the first channel, the main stream coding information, and the sub stream coding information, wherein the playlist, in response to that a client sends a channel change instruction, instructs the client to perform channel change according to the main stream and the sub stream.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the separately encoding the live stream of the first channel in different coding manners, to generate both a main stream and a sub stream comprises:
encoding the live stream of the first channel using a video coding standard, to generate the main stream; and
encoding the live stream of the first channel using the video coding standard, and inserting an auxiliary frame into the live stream of the first channel, to generate the sub stream.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the auxiliary frame comprises a change I frame that is independently decodable and a change P frame that is decoded depending on the change I frame, and
the inserting an auxiliary frame into the live stream of the first channel, to generate the sub stream specifically comprises sequentially inserting the change I frame and the change P frame into each media file in the N media file sets comprised in the live stream of the first channel, wherein the change I frame and the change P frame are used to provide the sub stream with more stream access points than the main stream.

### Claim 4 (depends on 3)

The method according to claim 3, wherein each of the n media files comprises one or more group of pictures (GOPs), and each GOP comprises two or more image frames; and
the sequentially inserting the change I frame and the change P frame specifically comprises: sequentially inserting the change I frame and the change P frame according to preset density, wherein the preset density is specified according to a length of the GOP, and the length of the GOP is represented by a quantity of image frames comprised in the GOP.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the playlist of the first channel comprises the main stream coding information, the sub stream coding information, an ID of the first channel, and a download link of a media file comprised in the N media file sets.

### Claim 6

A channel change method, applied to an Over The Top (OTT) video service, wherein the method comprises:
sending a channel change instruction;
stopping obtaining a media file of a currently played channel;
requesting a playlist of a first channel from a server, wherein the first channel is a new channel that is a change target and that is indicated by the channel change instruction;
receiving the playlist of the first channel; and
performing channel change according to the playlist of the first channel, a main stream, and a sub stream, wherein the main stream and the sub stream are obtained by separately encoding a live stream of the first channel in different coding manners.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the playlist of the first channel comprises coding information of the main stream, coding information of the sub stream, an ID of the first channel, and a download link of a media file in N media file sets comprised in the live stream of the first channel, and N is an integer greater than or equal to 1.

### Claim 8 (depends on 7)

The method according to claim 7, wherein the performing channel change according to the playlist of the first channel, a main stream, and a sub stream comprises:
selecting, according to the playlist of the first channel, stream access points in the sub stream that are closest to a receiving moment of the channel change instruction;
downloading, according to the download link that is in the playlist of the first channel and that is of the media file comprised in the N media file sets, an image frame that is not played in a current media file; and
playing the image frame, wherein the current media file is a media file that is in the sub stream and in which image frames that are in a one-to-one correspondence with the closest stream access points are located; and if playing of all image frames in the current media file is completed, switching to play a next media file that is in the main stream and that is of a media file in a one-to-one correspondence with the current media file.

### Claim 9 (depends on 8)

The method according to claim 8, wherein the method further comprises:
after the downloading an image frame that is not played in a current media file, downloading, before playing of all the image frames in the current media file is completed, the next media file that is in the main stream and that is of the media file in a one-to-one correspondence with the current media file.

### Claim 10 (depends on 6)

The method according to claim 6, wherein that the main stream and the sub stream are obtained by separately encoding the live stream of the first channel in different coding manners specifically comprises:
the main stream is generated using a video coding standard to encode the live stream of the first channel; and
the sub stream is generated using the video coding standard to encode the live stream of the first channel and inserting an auxiliary frame into the live stream of the first channel.

### Claim 11 (depends on 10)

The method according to claim 10, wherein the auxiliary frame comprises a change I frame that is independently decodable and a change P frame that is decoded depending on the change I frame, and that the auxiliary frame is inserted into the live stream of the first channel specifically comprises:
sequentially inserting, according to preset density, the change I frame and the change P frame into each media file in N media file sets comprised in the live stream of the first channel, wherein the change I frame and the change P frame are used to provide the sub stream with more stream access points than the main stream.

### Claim 12

A server supporting channel change, applied to an Over The Top (OTT) video service, wherein the server comprises a transmit port, a receive port, a bus, at least one processor, and a non-transitory computer-readable storage medium coupled to the at least one processor and storing programming instructions for execution by the at least one processor, the bus is configured to connect the transmit port, the receive port, the at least one processor, and the non-transitory computer-readable storage medium;
wherein the receive port is configured to receive a live stream of a first channel, wherein the live stream of the first channel comprises N media file sets;
wherein the programming instructions instruct the at least one processor to separately encode the live stream of the first channel in different coding manners, to generate both a main stream and a sub stream, wherein the main stream comprises the N media file sets and main stream coding information, the sub stream comprises the N media file sets and sub stream coding information, the main stream is used for live broadcast, and the sub stream is used for channel change;
wherein the programming instructions further instruct the at least one processor to generate a playlist of the first channel according to channel information of the first channel, the main stream coding information, and the sub stream coding information, wherein the playlist, in response to that a client sends a channel change instruction, instructs the client to perform channel change according to the main stream and the sub stream; and
wherein the transmit port is configured to send the playlist of the first channel.

### Claim 13 (depends on 12)

The server according to claim 12, wherein the programming instructions instruct the at least one processor:
encode the live stream of the first channel by using a video coding standard, to generate the main stream; and
encode the live stream of the first channel by using the video coding standard, and insert an auxiliary frame into the live stream of the first channel, to generate the sub stream.

### Claim 14 (depends on 13)

The server according to claim 13, wherein the auxiliary frame comprises a change I frame that is independently decodable and a change P frame that is decoded depending on the change I frame, and the programming instructions instruct the at least one processor to:
sequentially insert the change I frame and the change P frame into each media file in the N media file sets comprised in the live stream of the first channel, wherein the change I frame and the change P frame are used to provide the sub stream with more stream access points than the main stream.

### Claim 15 (depends on 14)

The server according to claim 14, wherein each of the n media files comprises one or more GOPs, group of pictures, and each GOP comprises two or more image frames; and
wherein the programming instructions instruct the at least one processor to sequentially insert the change I frame and the change P frame according to preset density, wherein the preset density is specified according to a length of the GOP, and the length of the GOP is represented by a quantity of image frames comprised in the GOP.

### Claim 16 (depends on 12)

The server according to claim 12, wherein the playlist of the first channel comprises the main stream coding information, the sub stream coding information, an ID of the first channel, and a download link of a media file comprised in the N media file sets.

### Claim 17

A terminal supporting channel change, applied to an OTT video service, wherein the terminal comprises a transmitter, a receiver, at least one processor and a non-transitory computer-readable storage medium coupled to the at least one processor and storing programming instructions for execution by the at least one processor;
the transmitter is configured to: send a channel change instruction, and stop obtaining a media file of a currently played channel;
the transmitter is further configured to send a request to a server, wherein the request requests a playlist of a first channel, and the first channel is a new channel that is a change target and that is indicated by the channel change instruction;
the receiver is configured to receive the playlist of the first channel; and
the programming instructions instruct the at least one processor to perform channel change according to the playlist of the first channel, a main stream, and a sub stream, wherein the main stream and the sub stream are obtained by separately encoding a live stream of the first channel in different coding manners.

### Claim 18 (depends on 17)

The terminal according to claim 17, wherein the playlist of the first channel comprises coding information of the main stream, coding information of the sub stream, an ID of the first channel, and a download link of a media file in N media file sets comprised in the live stream of the first channel, and N is an integer greater than or equal to 1.

### Claim 19 (depends on 18)

The terminal according to claim 18, wherein the programming instructions instruct the at least one processor to:
select, according to the playlist of the first channel, stream access points in the sub stream that are closest to a receiving moment of the channel change instruction;
download, according to the download link that is in the playlist of the first channel and that is of the media file comprised in the N media file sets, an image frame that is not played in a current media file; and
play the image frame, wherein the current media file is a media file that is in the sub stream and in which image frames that are in a one-to-one correspondence with the closest stream access points are located; and
if playing of all image frames in the current media file is completed, switch to play a next media file that is in the main stream and that is of a media file in a one-to-one correspondence with the current media file.

### Claim 20 (depends on 19)

The terminal according to claim 19, wherein the programming instructions instruct the at least one processor to:
after the image frame that is not played in the current media file is downloaded, download, before playing of all the image frames in the current media file is completed, the next media file that is in the main stream and that is of the media file in a one-to-one correspondence with the current media file.

### Claim 21 (depends on 17)

The terminal according to claim 17, wherein that the main stream and the sub stream are obtained by separately encoding the live stream of the first channel in different coding manners specifically comprises:
wherein the main stream is generated using a video coding standard to encode the live stream of the first channel; and
wherein the sub stream is generated using the video coding standard to encode the live stream of the first channel and inserting an auxiliary frame into the live stream of the first channel.

### Claim 22 (depends on 21)

The terminal according to claim 21, wherein the auxiliary frame comprises a change I frame that is independently decodable and a change P frame that is decoded depending on the change I frame, and that the auxiliary frame is inserted into the live stream of the first channel specifically comprises:
wherein the change I frame and the change P frame are sequentially inserting, according to preset density, into each media file in N media file sets comprised in the live stream of the first channel, wherein the change I frame and the change P frame are used to provide the sub stream with more stream access points than the main stream.