JP4635801B2 - Information processing apparatus and information processing method - Google Patents

Description

  The present invention relates to an information processing apparatus and an information processing apparatus suitable for, for example, a mobile phone having a streaming reproduction function, and more particularly to an information processing apparatus and an information processing method for preventing unnecessary reception of a stream that cannot be reproduced.

  For transmission of audio data and / or image data (hereinafter collectively referred to as content data) via a network, a download transmission system and a stream transmission system (hereinafter also referred to as streaming) are used. There is. In the download type transmission method, the content data file transmitted from the distribution server is temporarily copied on the client terminal (device) side, and then the content data such as video of the content data file is reproduced. For this reason, this download type transmission method cannot reproduce data on the terminal side until the file transfer is completed, and is not suitable for reproducing video data or the like for a long time.

  On the other hand, streaming is a method in which the client terminal sequentially reproduces in real time while receiving a continuous flow of digital signals, and the data received on the client terminal side even during transmission from the stream server to the client terminal. Is played. This streaming mainly uses a protocol called RTP (Real-Time Transport Protocol) defined in RFC1889 of Internet Engineering Task Force (IETF).

  Usually, in streaming by RTP, data for a certain time is accumulated in a buffer before starting playback so that continuous playback is possible, and then playback is started. However, whether or not parameter values such as a sampling frequency in audio data and a frame interval value in image data are compatible with a device that reproduces content, even though the audio / image encoding method itself is compatible. It is unknown. Therefore, it is necessary to actually reproduce and discriminate it from the header information. If it is not supported, reproduction becomes impossible due to a parameter error immediately after the reproduction is started.

For example, Patent Document 1 discloses a recording apparatus that detects an error such as a format violation or syntax violation with an error checker for an input stream and records error information together with the stream. Depending on the error level of the error information, at the time of reproduction, the error processing unit can perform processing according to the error level such as blocking output or correcting the header. Further, this Patent Document 1 discloses a reproducing apparatus that performs reproduction after performing a predetermined error process when an error is detected, or interrupts output.
JP 2001-169251 A

  However, as described above, in streaming by RTP, data for a certain period of time is accumulated in a buffer before starting playback so that continuous playback is possible, and then playback is started. Therefore, as in the technique described in Patent Document 1, if it is detected that playback is impossible after actual playback, the data stored in the buffer is wasted. For example, in a mobile phone, unnecessary packets are reduced accordingly. The packet reception fee is wasted. In particular, in the case of a mobile phone network, since the line speed is slower than that of a high-speed line network such as ADSL, it takes more time to store in the buffer and it takes time to detect whether or not playback is possible. is there.

  The present invention has been made to solve such problems, and an object thereof is to provide an information processing apparatus and an information processing method capable of minimizing reception of unnecessary data that cannot be reproduced. To do.

In order to achieve the above-described object, an information processing apparatus according to the present invention includes a receiving unit that receives an encoded content stream, a decoding unit that decodes the stream, and the content based on a decoding result of the decoding unit. A control unit that controls reception refusal of the stream, and the decoding unit determines whether or not the stream can be played based on a result of decoding minimum data for determining whether or not the device can play back, and control unit is first to receive only the minimum data to said receiving unit, the decoding unit is a one to resume reception of the stream when it is determined that the reproducible, the minimum data, the This is header information of the content stream .

  In the present invention, prior to receiving a stream, only the minimum data of the stream is first received, and this is decoded to determine whether or not it can be played back by the device. By receiving, useless data that cannot be reproduced even if it is received is received except for the minimum data.

  In addition, the decoding unit can determine whether or not the reproduction is possible based on the header information of the content included in the minimum data that has been decoded, and can determine whether or not the reproduction is possible based on the header information.

  In this case, the decoding unit can determine whether or not the reproduction is possible depending on whether or not the parameter value of the stream corresponds to a device.

  For example, the content may be audio data, and the parameter value may include a sampling frequency, or the content may be video data, and the parameter value may include a frame interval.

  The minimum data may include at least one frame data. As the minimum data, it is possible to determine whether reproduction is possible by decoding one frame data.

  Furthermore, it has a buffer for buffering the stream when streaming the stream, and the minimum data can be less than data buffered in the buffer when streaming. Since it is determined whether or not playback is possible based on data, data that may be wasted more than the minimum data that would normally be buffered by the start of streaming is not received until it is determined whether or not playback is possible.

  Furthermore, the control unit can cause the reception unit to start receiving a stream after the minimum data when the decoding unit determines that the reproduction is possible. The data can be used for normal reproduction without being received again.

  In addition, when the decoding unit determines that the decoding unit can reproduce, the control unit can cause the reception unit to start reception from the beginning of the stream, discard the minimum data, and start from the beginning of the stream as usual. Processing can be simplified by starting reception.

  Furthermore, the control unit can cause the reception unit to receive a stream in a format format corresponding to the device, and can reject reception before receiving the minimum data when the format format is different.

  Furthermore, it has an output unit that reproduces and outputs the decoded data decoded by the decoding unit, and when the decoding unit determines that reproduction is not possible, the control unit causes the reproduction output unit to output that effect. It is possible to notify the user that playback is impossible.

  Further, the present invention can be applied to a mobile phone having a streaming reproduction function by RTP. In a device such as a cellular phone that charges a packet fee, it is possible to determine whether or not a stream can be reproduced with a minimum amount of data, and avoid payment of a reception fee due to useless reception.

The information processing method according to the present invention receives only the minimum data having one frame data including at least header information of the content stream before starting to receive the encoded content stream, Whether or not the stream can be reproduced is determined based on the result of decoding, and when it is determined that reproduction is possible, reception of the content stream is started.

  According to the present invention, since it is confirmed whether or not it can be played back by a device with minimum data, and all contents are received after confirming that playback is possible, it is possible to receive content that cannot be played back. Absent.

  According to the present invention, it is possible to provide an information processing apparatus and an information processing apparatus that can prevent unnecessary streams from being received by determining whether or not reproduction is possible with a small amount of data in a short time.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. In this embodiment, the present invention is applied to a mobile phone having a streaming reproduction function by RTP. Note that in this embodiment, a mobile phone is described as an example of an information processing apparatus, but the present invention can be applied to a device capable of receiving a stream, such as a personal computer or a mobile device.

  FIG. 1 is a schematic diagram showing an information system 10 according to an embodiment of the present invention. As shown in FIG. 1, the information system 10 includes a content server 1 that provides content and a mobile phone 2.

  The content server 1 stores content for RTP streaming, and uses RTSP (Real-Time Streaming Protocol: stipulated by RFC2326) / RTP protocol to stream content for the user. Distribute to a certain mobile phone 2.

  The data transmitter / receiver 3 has a function of transmitting / receiving a content stream (RTP data) via wireless. The RTP buffer 4 has a function of accumulating RTP data received from the content server 1. After a predetermined amount of RTP data is stored in the RTP buffer 4, data decoding / reproduction is started.

  The RTP / RTSP analysis unit 5 analyzes the RTP packet received from the RTP buffer 4 by analyzing the RTSP packet transmission / reception with the content server 1, converts it into encoded frame data, and transmits it to the decoding unit 6. Has the function of

  The decoding unit 6 decodes the received data and transmits it to the output unit 7. In addition, the decoding unit according to the present embodiment performs a parameter check on initial accumulated data as minimum data including at least one frame, and determines whether or not reproduction is possible.

  The output unit 7 has a function of outputting the moving image / audio data received from the decoding unit 6. Also, it has a function of outputting a message to that effect when it is determined that reproduction by the decoding unit 6 is impossible. For example, in the case of having a display screen, a character notifying that playback is impossible, such as an error, is output on the display screen. Or you may make it notify with an audio | voice.

  Here, the mobile phone 2 according to the present embodiment has a streaming playback function based on RTP, and early detects whether playback is possible by decoding and analyzing the streaming. For this reason, when there is content to be received (reproduced), the mobile phone 2 first receives only the minimum data necessary for analysis prior to receiving the content stream, and the header information of the received minimum data is received. When a certain parameter value is analyzed and the mobile phone is a non-compliant parameter, the reception is immediately stopped and an unnecessary RTP packet is not received. FIG. 2 is a diagram for explaining this function.

  As shown in FIG. 2, when a streaming start request for content C is made from the mobile phone 2 to the content server 1, first, initial storage data is sequentially stored in the RTP buffer 4 by packet transmission by RTP from the content server 1. Accumulate. Here, by normally storing the data D2 for a predetermined time as the initial storage data, it is possible to execute streaming playback that is played back while being received. On the other hand, in the present embodiment, accumulation is performed only for a minimum amount of data D1 that is less than a certain amount of data D2 and that can be checked for parameters.

  Next, the initially stored data D1 is transmitted to the decoding unit 6 to perform parameter check. As a result of the parameter check, if the parameter is compatible with reproduction by the decoding unit 6, data is accumulated in the RTP buffer 4 up to the initial accumulated data amount D2 as usual, and streaming is started. On the other hand, as a result of the parameter check, if the parameter is incompatible with the reproduction in the decoding unit 6, since the reproduction is not possible with the mobile phone 2, the streaming is stopped. In this case, data storage up to the normal initial storage data amount D2 is not performed.

  In other words, in order to receive only the minimum necessary data (minimum data) in advance, check whether playback is possible, and determine whether to receive it. In addition, it is possible to receive only the minimum data, and to receive data that is normally stored as the initial stored data D2, thereby eliminating unnecessary consumption of the packet cost and shortening the time until detection of whether or not reproduction is possible.

  FIG. 3 shows the relationship between the amount of content data and the playback time in the present embodiment. A time corresponding to the total data amount C, that is, a time corresponding to the total reproduction of the content is defined as t3. In addition, the reproduction time corresponding to the normal initial accumulated data amount is t2, and the initial accumulated data amount in this embodiment, that is, the time corresponding to the minimum data amount necessary for the parameter check is t1.

  When normal streaming playback is performed, the stream up to the playback time t2 is buffered in advance and then decoded and played back while being received. When playback is impossible, the stream up to t2 is received. Then it becomes. On the other hand, in the present embodiment, since the minimum data up to t1 is analyzed to determine whether or not playback is possible, it is not necessary to receive packets for t3-t2, and reception of unnecessary packets is prevented. Can do.

  4 and 5 are flowcharts showing the information processing method in the present embodiment. That is, FIG. 4 and FIG. 5 show a method in which only minimum data is received in advance before stream reception, and whether or not stream reception is permitted after determining whether or not reproduction is possible.

  When accessing the RTP streaming content from the mobile phone 2, first, the RTP / RTSP analysis unit 5 issues a connection information request (DESCRIBE) message by RTSP to the content server 1, and video or audio data ( Request information required to receive (content). The mobile phone 2 receives an OK response from the content server 1 and receives an SDP (Session Description Protocol). Next, when a session (connection) establishment request (SETUP message) is transmitted, a session is established by receiving an OK response from the content server 1 (step S1). In this way, information exchange and reproduction preparation regarding content reproduction are performed.

  Next, a playback start request (data acquisition request) by a PLAY message is transmitted from the RTP / RTSP analysis unit 5 to the content server 1 (step S2). At this time, the playback section is designated by the “Range” parameter. Here, in a normal case, “npt = 0−t3” (see FIG. 3) corresponding to the total data amount (C) of the content is designated, but in this embodiment, the minimum required for parameter check In order to acquire only the data amount (D1) which is the limit data, “npt = 0−t1” is designated (step S3). When an OK response is received from the content server 1 (step S4), data transmission by RTP starts from the content server 1. Thus, RTP packets are transmitted until the data D1 is accumulated in the RTP buffer 4 (step S5). As described above, since parameter specification of Range: npt = 0−t1 ”is performed in step S3, the data transmitted from the content server 1 is only the data amount D1 necessary for the parameter check.

  When the data amount D1 necessary for parameter check is accumulated in the RTP buffer 4, the accumulated data D1 is transmitted from the RTP buffer 4 to the RTP / RTSP analysis unit 5. The RTP / RTSP analysis unit 5 converts this data into frame data and transmits it to the decoding unit 6 for parameter check (step S6). At this time, the frame data is also stored in the RTP / RTSP analysis unit 5 as it is. The decoding unit 6 that has received the frame data performs a parameter check, determines whether or not the content data can be reproduced (step S7), and returns the result to the RTP / RTSP analysis unit 5.

  If the determination result in the decoding unit 6 is not reproducible (step S8: No), the RTP / RTSP analysis unit 5 discards the frame data stored in step S6 (step S9) and sends it to the output unit 7. “Reproduction impossible” is displayed (step S10). Then, the RTP / RTSP analysis unit 5 transmits a TEARDOWN message requesting the stop of stream distribution to the content server 1, receives an OK response from the content server 1, and stops streaming (step S11).

  On the other hand, if the determination result in the decryption unit 6 is “reproducible” (step S8: Yes), as shown in FIG. 5, a data acquisition request PLAY message is again sent from the RTP / RTSP analysis unit 5 to the content server 1. (Step S12). At this time, since the data D1 necessary for the parameter check has already been acquired, “npt = t1−t3” is designated for the “Range” parameter (step S13). Then, an OK response is received from the content server 1 (step S14), and data transmission by RTP is resumed from the content server 1. As a result, RTP packets for time t1 to t3 are transmitted from the content server 1, and the content is stored in the RTP buffer 4. When the data up to time t2 corresponding to the normal initial accumulated data amount D2 is accumulated in the RTP buffer 4, the mobile phone 2 starts reproduction (step S16). At the start of reproduction, the parameter check data amount (time 0 to t1) is stored in the RTP / RTSP analysis unit 5 in step S6 described above. Therefore, this is first transmitted to the decoding unit 6 for reproduction (step S17). In addition, the remaining data in the RTP buffer 4 is sent to the RTP / RTSP analysis unit 5 to be converted into frame data and supplied to the decoding unit 6.

  After this, all the RTP packets of the content C are sequentially transmitted from the content server 1 sequentially (step S18). Therefore, the operation of accumulating the RTP packets in the RTP buffer 4 and the frame data are sequentially converted and decoded by the RTP / RTSP analysis unit 5. The operation of transmitting to the unit 6 and reproducing is performed in parallel, and normal streaming reproduction is performed (step S19).

  According to the present invention, even content that does not support parameter values in a mobile phone can be checked with only the minimum necessary data, thereby eliminating unnecessary consumption of packet charges and reducing time to detection. can do.

  It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. For example, in the present embodiment, the parameter check data amount is stored in step S6. Therefore, in the parameter designation in step S13, the parameter check data amount is specified not to be received again. Instead of saving the data D2 in step S6, it is also possible to specify “Range: npt = 0−t3” in step S13 and receive the data from the beginning of the content. As a result, processing equivalent to normal streaming can be performed, and processing can be simplified.

  Also, arbitrary processing executed by each block in the above-described embodiment can be realized by causing a CPU (Central Processing Unit) to execute a computer program. In this case, the computer program can be provided by being recorded on a recording medium, or can be provided by being transmitted via the Internet or another transmission medium.

It is a schematic diagram which shows the information system containing the mobile telephone concerning embodiment of this invention. FIG. 10 is a diagram for explaining a function of stopping reception and not receiving unnecessary RTP packets when the mobile phone according to the embodiment of the present invention has incompatible parameters. 3 shows the relationship between content data amount and playback time in an embodiment of the present invention. It is a figure which shows the information processing method in embodiment of this invention, Comprising: It is a flowchart which shows the method of determining permission of stream reception after determining reproduction | regeneration permission with minimum data before stream reception. Similarly, it is a figure which shows the information processing method in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Content server 2 Mobile telephone 3 Data transmission / reception part 4 RTP buffer 5 RTP / RTSP analysis part 6 Decoding part 7 Output part 10 Information system

Claims (14)

A receiving unit for receiving the encoded content stream;
A decoding unit for decoding the stream;
A control unit that controls reception refusal of the content stream based on a decoding result of the decoding unit;
The decoding unit determines whether or not the stream can be played based on the result of decoding the minimum data for determining whether or not the device can play back,
The control unit first causes the reception unit to receive only the minimum data, and resumes reception of the stream when the decoding unit determines that reproduction is possible ,
The information processing apparatus , wherein the minimum data is header information of the content stream . The information according to claim 1, wherein the decoding unit analyzes header information of content included in the decoded minimum data, and determines whether or not the reproduction is possible based on an encoding parameter included in the header information. Processing equipment. The information processing apparatus according to claim 2, wherein the decoding unit determines whether or not the reproduction is possible based on whether or not a parameter value of the stream corresponds to a device. The information processing apparatus according to claim 3, wherein the content is audio data, and the parameter value includes a sampling frequency. The information processing apparatus according to claim 3, wherein the content is video data, and the parameter value includes a frame interval. The information processing apparatus according to claim 1, wherein the minimum data includes at least one frame data. A buffer for buffering the stream when streaming the stream;
The information processing apparatus according to claim 1, wherein the minimum data is less than data buffered in the buffer when the streaming reproduction is performed. The said control part makes the said reception part start reception of the stream after the said minimum data, when it determines with the said decoding part being reproducible, The any one of Claim 1 thru | or 7 characterized by the above-mentioned. Information processing device. 8. The information processing according to claim 1, wherein the control unit causes the reception unit to start reception from the head of the stream when the decoding unit determines that reproduction is possible. 9. apparatus. The information processing apparatus according to claim 1, wherein the control unit causes the reception unit to receive a stream in a format format corresponding to a device. An output unit that reproduces and outputs the decoded data decoded by the decoding unit;
11. The information processing apparatus according to claim 1, wherein, when the decoding unit determines that reproduction is not possible, the control unit causes the reproduction output unit to output that effect. 12. The information processing apparatus according to claim 1, wherein the information processing apparatus is a mobile phone having a streaming reproduction function based on RTP. Before starting to receive the encoded content stream, only the minimum data having one frame data including at least header information of the content stream is received,
Determining whether or not the stream can be reproduced based on a result of decoding the minimum data;
An information processing method for starting reception of the content stream when it is determined that reproduction is possible. 14. The determination according to claim 13, wherein when determining whether or not the reproduction is possible, the header information of the decoded minimum data is analyzed, and whether or not the reproduction is possible is determined based on an encoding parameter included in the header information. Information processing method.

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