CN100589553C - A method for playing scrambled TV programs on a mobile TV terminal - Google Patents

Abstract

The invention discloses a method for playing a scrambled TV program on a mobile phone TV terminal, comprising: the streaming media platform judges whether the program to be played by the SDP file is scrambled or not according to whether there is an m=data line in the received Session Description Protocol SDP file; scrambled program stream, if so, go to the next step; the key management system agent KDA of the conditional access system generates a key according to the received authorization management message EMM and authorization control information ECM, and sends it to the descrambler; the streaming media platform The received scrambled TV program data is sent to the descrambler, and the descrambler decrypts the encrypted data, and sends the decrypted data back to the video and audio decoders for decoding and playback. The invention does not change the original program structure of the streaming media platform, has clear flow, is easy to implement, and is stable. And if the cache of encrypted video and audio data and the cache of decrypted video and audio data are the same, the efficiency can be greatly improved.

Description

A method for playing scrambled TV programs on a mobile TV terminal

technical field

The invention relates to the field of mobile TV, in particular to a method for playing scrambled TV programs on a mobile TV terminal.

Background technique

The streaming media platform of the mobile TV terminal is a development platform for playing streaming media. Usually, a streaming connection is established according to an SDP (Session Description Protocol) file, and RTP (Real-time Transport Protocol) data is received, and then video and audio data are analyzed and sent to the video , The audio decoder plays the streaming media, all of which are unencrypted audio and video streams. Currently more commonly used streaming media development platforms (such as Qualcomm's QTV platform) cannot play encrypted audio and video streams.

Conditional Access (CA, Conditional Access) technology is a technology for encrypting and decrypting streaming media that comes with DVB (Digital Video Broadcasting). Mainstream technologies follow the Open Security Framework (Open Security Framework). Its structure diagram is shown in Figure 1. On the terminal side, the conditional access system mainly includes KDA (KMS device agent, key management system agent), UICC (smart card), and Descrambler (descrambler). Multimedia streams are descrambled.

However, this open security framework does not propose how to use a descrambler to descramble encrypted audio and video streams so as to play scrambled TV programs; moreover, issues such as efficiency and stability need to be considered during descrambling.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for playing scrambled TV programs on a mobile phone TV terminal, so as to realize descrambling encrypted audio and video streams through a descrambler, thereby playing scrambled TV programs.

In order to solve the above-mentioned technical problems, the present invention provides a method for playing a scrambled TV program on a mobile phone TV terminal, comprising the following steps:

(1) Streaming media platform judges whether the program that this SDP file will play is the program flow of scrambling according to whether m=data line is arranged in the session description agreement SDP file that receives, if so, then execute step (2);

(2) The key management system agent KDA of the conditional access system generates a key according to the received authorization management message EMM and authorization control information ECM, and sends it to the descrambler;

(3) The streaming media platform sends the received scrambled TV program data into the descrambler, and the descrambler uses the key to descramble the scrambled TV program data;

(4) The streaming media platform decrypts the descrambled streaming media data to obtain audio and video data, and sends the audio and video data back to the audio and video decoder for decoding and playing.

Further, in the step (1), if it is determined that the program to be played by the SDP file is a scrambled program stream, it is identified that the current session is playing a scrambled program.

Further, in the step (1), if it is judged that the program to be played by the SDP file is a scrambled program stream, then identify the IP and the port of the ECM stream according to the m=data row of the SDP file; conditional access The KDA of the system connects to the network and receives the ECM flow according to the IP and port of the ECM flow.

Further, in the step (1), the streaming media platform also recognizes IP and ports of video and audio streams according to the m=video and m=audio lines of the SDP file, connects to the network, and receives audio and video data streams.

Further, the method further includes: storing the encrypted audio-video data and the decrypted audio-video data in the same buffer.

The invention does not change the original program structure of the streaming media platform, has clear flow, is easy to implement, and is stable. And if the cache of encrypted video and audio data and the cache of decrypted video and audio data are the same, the efficiency can be greatly improved.

Description of drawings

FIG. 1 is a schematic structural diagram of an open security framework;

The system block diagram of the embodiment of the present invention of Fig. 2;

Fig. 3 is a flowchart of an application example of the present invention.

Detailed ways

Currently, the commonly used streaming media development platforms (such as Qualcomm's QTV platform) do not include a Descrambler (descrambler). If you want to play a scrambled channel, you need to add a Descrambler (descrambler) for descrambling.

As shown in Figure 2, a Descrambler (descrambler) is added to the CAS (Conditional Access System) terminal side to cooperate with the streaming media platform to play scrambled TV programs. If it is a non-scrambled program, the streaming media platform will work in the normal way, analyze the data output by the mobile phone TV chip and send it to the video and audio decoder for decoding and playback; if it is a scrambled program, send the encrypted RTP data to To the streaming media platform, the streaming media platform sends the data to the descrambler for descrambling, and sends the descrambled plaintext streaming data back to the streaming media platform, and the streaming media platform analyzes it again, and sends the video and audio to the video , Audio decoder decoding playback.

This embodiment includes the following steps:

Step 1, the streaming media platform identifies the IP and port of the video and audio streams according to the m=video and m=audio lines of the SDP (Session Description Protocol) file, connects to the network, and receives the audio and video data streams.

Step 2, the streaming media platform recognizes the IP and the port of the ECM (Entitlement Control Message) stream according to the m=data row of the SDP file, and simultaneously judges that the program to be played by this SDP (Session Description Protocol) file is a scrambled program stream, and Indicates that the current session is playing a scrambled program.

Wherein, step 1 and step 2 can be executed in parallel;

The usual streaming media platforms play non-encrypted audio and video streams, and the audio and video program streams can be played normally after the steps are executed; the usual streaming media platforms cannot work when they want to play encrypted audio and video streams. According to the existence of the m=data line in the SDP (Session Description Protocol) file, the embodiment determines that it is an encrypted audio and video stream, and identifies that the current session is playing a scrambled program.

Step 3, if it is determined that it is a scrambled channel, KDA connects to the network according to the IP and port of the ECM (Entitlement Control Message, authorization control information) flow, and receives the ECM flow; KDA receives the EMM (Entitlement Management Message, authorization management information) Generate Control World (control word, ie key) with ECM data, and send the control word to the descrambler. The descrambler is ready to start working. Among them, the receiving process of EMM is to find the IP address and port of EMM according to the SDP file corresponding to EMM, and start to establish a connection after KDA is started, and has been monitoring and receiving data.

Step 4, the streaming media platform establishes a session connection, receives video and audio data, and uses different channel numbers to indicate whether it is video or audio streams. When receiving video and audio streams, for non-encrypted video and audio streams Send this data directly to the video and audio decoder for decoding and playback; for encrypted video and audio streams, send the received encrypted data to the descrambler, and the descrambler works, and sends the decrypted data back to the video and audio The decoder performs decoding and playback.

In order to improve efficiency, the Buffer (cache) of the encrypted video and audio data and the decrypted video and audio data Buffer are preferably the same.

As shown in Figure 3, a specific application example includes the following steps:

Step 301, the TV player requests to play the channel selected by the user;

Step 302, the multimedia platform obtains the SDP file corresponding to this channel through the mobile phone TV chip;

Step 303, the multimedia platform analyzes the SDP file, and executes two parallel processes of A and B;

A branch process:

Step 304, searching for the m=data row according to the SDP file;

Step 305, judging whether to include m=data row;

Step 306; If do not comprise m=data line, then the channel (channel) of identification this video, audio frequency is not the channel of encrypting, finishes and carries out A branch flow process;

Step 307, if comprise m=data line, then mark this video, the channel of audio frequency is the channel of encryption;

Step 308, the streaming media platform recognizes the IP and the port of the ECM flow according to the m=data line of the SDP file;

Step 309, the KDA of the conditional access system connects to the network according to the IP and port of the ECM flow, and receives the ECM flow;

Step 310, KDA generates Control World (control word, i.e. key) according to received EMM and ECM data; Descrambler is in ready state, can start working, ends A branch process;

B branch process:

Step 311, according to m=video of SDP file, m=audio row identification video, IP and the port of audio stream;

Step 312, connect to the network, establish video and audio connections, and receive video and audio data streams;

Step 313, judge whether the channel is encrypted according to the identification of steps 306 and 307, if not encrypted, then perform step 316; if encrypted, then enter the next step;

Step 314, sending the encrypted video and audio data into the descrambler for descrambling, this step needs to be carried out after step 310 is completed;

Step 315, judging whether the descrambling is successful, if not successful, then end the B branch process; if successful, then execute the next step;

Step 316, send the decrypted data back to the video and audio decoder for decoding and playing, and end the B branch process.

The present invention can easily expand and add a descrambler based on the streaming media platform to descramble encrypted audio and video streams to play scrambled TV programs; at the same time, the present invention ensures the integrity of the original streaming media platform, and is efficient and stable. It is simple, and provides a method for quickly implementing mobile TV terminals to play scrambled TV programs based on streaming media platforms.

Claims (5)

1. A method for playing a scrambled TV program on a mobile TV terminal, characterized in that, comprising the steps: (1) Streaming media platform judges whether the program to be played by this SDP file is an scrambled program stream according to whether m=data line is arranged in the session description protocol SDP file received, if so, then execute step (2), otherwise it will The data output by the mobile phone chip is analyzed and sent to the video and audio decoder for playback; (2) Add a descrambler on the terminal side of the conditional access system, the key management system agent KDA of the conditional access system generates a key according to the received authorization management message EMM and authorization control information ECM, and sends it to the descrambler device; (3) The streaming media platform sends the received scrambled TV program data into the descrambler, and the descrambler uses the key to descramble the scrambled TV program data; (4) The streaming media platform decrypts the descrambled streaming media data to obtain audio and video data, and sends the audio and video data back to the audio and video decoder for decoding and playing. 2. The method according to claim 1, characterized in that, in the step (1), if it is judged that the program to be played by the SDP file is a scrambled program stream, then it is scrambled that the current session is played program. 3. The method according to claim 1, characterized in that, in the step (1), if it is judged that the program to be played by the SDP file is a scrambled program stream, then according to the m=data row of the SDP file Identify the IP and port of the ECM flow; the KDA of the conditional access system connects to the network and receives the ECM flow according to the IP and port of the ECM flow. 4. method according to claim 1, it is characterized in that, in described step (1), streaming media platform is also according to m=video of SDP file, m=audio row identification video, IP and the port of audio stream, connect Network, receiving audio and video data streams. 5. The method according to claim 1, further comprising: storing the encrypted audio-video data and the decrypted audio-video data in the same buffer.

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