JP2015056723A - Video server system and sound reproduction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To output a sound without damaging quality even if a reproduction apparatus performs fast double-speed reproduction.SOLUTION: This video server system comprises: an HD accumulation server for accumulating high-quality material data; a proxy accumulation server for accumulating low-quality material data; and the reproduction apparatus which acquires sound data from the HD accumulation server or the proxy accumulation server in accordance with a reproduction speed.

Description

  The present invention relates to a video server system, and more particularly to audio reproduction.

A playback device and an editing device in a video server system mainly acquire high-quality material data for main broadcast (hereinafter referred to as HD material) stored in a recording medium on the server via a network.
The HD material stored on the recording medium on the server has a large amount of data, and even if a high-speed recording medium, broadband network equipment, or high-speed processing technology is used, it takes a certain amount of time to complete the transfer to the playback device. Cost.
Also, since HD materials have a large amount of data, means such as pre-holding them in the playback device is not practical.

When previewing material in video server systems, it is often used as a substitute for HD material, and low-quality material data (hereinafter referred to as proxy material) with a reduced amount of data is generated when recording HD material. I have done it.
According to this use, since the amount of data is small, the transfer is quick, and it is possible to reduce the equipment load and network load of the video server system rather than using HD materials.

Video server systems that handle large-capacity HD materials are required to have extremely high processing capabilities in networks and servers.
In particular, when a playback device performs high-speed double-speed playback (hereinafter referred to as high-speed double-speed playback), the pitch of the sound changes due to a change in the playback speed.

  The method for changing the playback speed is, for example, (1) a method of transferring all the audio data in the playback section and resampling by the playback device, (2) a method of transferring the data by thinning out in advance by the data storage server, and (3) There are three methods of resampling at the data storage server and then transferring to the playback device.

  In the method (1) described above, the amount of audio data increases as much as the playback speed increases, so the network load is large. In addition, network equipment that assumes the maximum double speed playback is required.

  The above method (2) is based on, for example, a system adopting AVC-Intra 50 (bit depth 16 bits, sampling frequency 48 kHz, elementary stream (video data and audio data are independent and one file is used for audio 2ch)). In this case, the data storage server needs to read the stored data while thinning it out in units of 4 bytes. This increases the processing load on the data storage server.

  The method (3) described above is not appropriate as a function of the data storage server with respect to the method of resampling by the data storage server. Processing completely different from the original function is required, and the cost increases.

  Also, in the case of a video server system that combines both video and audio data and handles them in a format such as TS (Transport Stream), PS (Program Stream), etc., only the relevant frame for decoding at least for the video during double-speed playback is used. The playback device may acquire it, but since the entire audio is necessary, it is necessary to acquire all data in which video and audio are combined, which is not realistic in terms of both processing load and equipment load.

Double-speed playback on tape media such as HDCAM achieves audio output.
The device performance of recent playback devices can have a sufficient margin even when decoding HD material, which is generally considered to have a large processing load, and there is room for parallel processing of other tasks.

  In a tapeless system including a JOG controller, a terminal, a decoder control device, and a decoder, a technique is disclosed in which the decoder sends a playback command to the video server, receives a video file from the video server, and sends a decoded video signal. (For example, refer to Patent Document 1).

JP2011-217255A

  Conventional playback devices do not handle proxy materials at all for high-quality previews and editing operations, so it was not possible to reduce the equipment load and network load of the video server system by using proxy materials.

  In a video server system that always handles large-capacity HD materials, extremely high processing capacity is required in the network and server. In addition, due to the required performance, precise adjustments were required.

In conventional video server systems, the required audio data is transferred from the storage server to the playback device up to about twice the speed, and the playback device resamples and outputs the audio. In order to suppress the load of the voice, the voice data is not acquired and the voice output is not performed.
It is an object of the present invention to output audio without losing quality even when the playback device performs high-speed double-speed playback.

  The video server system of the present invention is a video server system having an HD storage server that stores high-quality material data, a proxy storage server that stores low-quality material data, and a playback device, and the playback device is in accordance with the playback speed. And obtaining audio data from the HD storage server or the proxy storage server.

  An audio playback method for a video server system according to the present invention is an audio playback method for a video server system having an HD storage server for storing high-quality material data, a proxy storage server for storing low-quality material data, and a playback device. The method includes a step of inputting a reproduction speed, a step of acquiring audio data from the HD storage server or the proxy storage server according to the reproduction speed, and a step of reproducing the audio data according to the reproduction speed.

  The audio reproduction method of the video server system according to the present invention is the above-described audio reproduction method, wherein when the reproduction speed input in the step of inputting the reproduction speed is three times or less, the audio data is acquired from the HD storage server. Features.

According to the present invention, it is possible to realize audio output without degrading the reproduction quality even when the reproduction apparatus performs high-speed double-speed reproduction.
When the playback device is limited to the use of audio of HD material, audio data is required according to the speed of double-speed playback. However, since the audio of proxy material is used, the required audio data capacity is proxy material for the audio of HD material. Therefore, the load of the server and the network can be reduced accordingly.

  Even in a video server system adopting the TS format or the PS format, the playback apparatus can realize audio output at the time of double speed playback by acquiring relatively small proxy material data.

  The double-speed playback sound of the playback device is generally realized by thinning out samples of the original sound by allowing a slight change in pitch due to a change in playback speed. Therefore, for example, even if the original sound is not of a high-density HD material with a sampling frequency, but is of a low-density proxy material with a relatively low sampling frequency, an audio sample with a playback speed above a certain level. Therefore, the audio that is finally reproduced and output has the same ratio of thinned samples as compared with the original audio, so that the reproduction quality at the time of double-speed reproduction is not impaired.

It is a figure for demonstrating the video server system which is one Example of this invention. It is a flowchart for demonstrating operation | movement of the video server system which is one Example of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram for explaining a video server system according to an embodiment of the present invention.
In FIG. 1, the video server system 100 includes an HD storage server 10, a proxy storage server 20, a playback device 30, a control device 40, a playback environment unit 50, and a network 60.
The network 60 is connected to the HD storage server 10, the proxy storage server 20, the playback device 30, and the control device 40.

The HD storage server 10 stores HD materials (high quality material data for broadcasting).
The proxy storage server 20 stores proxy material (low-grade material data with a reduced data amount as a substitute for HD material).

In this embodiment, it is assumed that the audio data of the proxy material is stored separately from the video data in the ES (Elementary Stream) format or in the data management on the proxy storage server 20.
Audio data can be reproduced from an audio sample at a designated reproduction position by using uncompressed fixed-length data, a streaming method, a frame table, or the like.
If the audio data is compressed data, it is transferred in units of compressed frames so that the specified audio sample can be normally decoded.

The playback device 30 plays back the data stored in the HD storage server 10 or the proxy storage server 20 at the same speed reproduction or at high speed reproduction.
The playback device 30 is connected to a network 60 on the video server system 100, and has a CPU (Central Processing Unit) 33 having a calculation capability necessary for various processes, a storage unit 32 that performs temporary storage, and an HD-SDI (High Definition). Processing and calculation by the playback device 40 having a video / audio output interface 31 such as a serial digital interface) is performed by interposing temporary storage in the CPU 33 or the storage unit 32.

The control device 40 controls each device in the video server system 100.
The reproduction environment unit 50 converts the audio signal 70 into a signal in a format suitable for the output destination environment.

Next, an example of the reproduction process performed by the reproduction apparatus 30 will be described.
The sampling frequency of the audio of the HD material is 48 kHz, whereas the sampling frequency of the audio of the proxy material is 16 kHz.
For example, the sound resampled to 48 kHz by the playback device 30 is played back and output at 1 × for 3 seconds at 1 channel.
At this time, if the playback device 30 uses only HD material, 144000 samples, which is 3 times the 48000 samples required for normal-speed playback, are acquired from the HD storage server 10 and are reduced to 1/3 according to the output of 48 kHz. It is necessary to thin out.

  On the other hand, when the playback device 30 uses the sound of the proxy material, it is necessary to acquire 3 times of 16000 samples necessary for the proxy material reproduction at the same speed, that is, 48000 samples of audio data, which is compared with the case of the HD material. One third is enough. In addition, since the number of samples coincides with the output 48 kHz, and excess or deficiency of samples due to resampling does not occur, as a result, sound quality equivalent to the case of using HD material audio can be obtained.

However, if the playback speed of the playback device 30 is less than 3 times speed, the voice of the proxy material lacks samples and requires interpolation, so the sound quality is impaired. Therefore, the object of the present invention can be achieved if the conditions are such that the proxy material audio data is used when the playback speed instruction is three times or more.
Depending on the use of the business, if it is acceptable even if the sound quality is somewhat impaired, such as for preview use, the load on the server and the network can be reduced by using the voice of the proxy material from, for example, a reproduction speed of twice or more.

Next, the operation of the video server system according to an embodiment of the present invention will be described with reference to FIG.
FIG. 2 is a flowchart for explaining the operation of the video server system according to the embodiment of the present invention.
In FIG. 2, the playback apparatus 30 receives a playback position and playback speed instruction (S100) from the control apparatus 40 as a playback condition instruction for a material.

  The playback device 30 determines the audio data to be used and the amount of data requested to the HD storage server 10 and the proxy storage server 20 based on the playback speed instruction content (S110). This process is executed not only once under the control, but also repeatedly as long as the playback device 30 continues playback in response to a playback position update or a retry associated with an acquisition timeout from the HD storage server 10 or the proxy storage server 20.

  The playback device 30 determines whether or not the playback speed designation exceeds 3 times. If the playback speed designation exceeds 3 times (YES), the process proceeds to S200, where the playback speed designation is 3. If it is less than or equal to double (NO), the process proceeds to S130.

  The playback device 30 makes a data request to the HD storage server 10 based on the designated playback position, the determined use audio data, and requested data amount information, and receives the HD audio data via the network 60 (S130). ).

When the audio data is compressed data, the playback device 30 performs HD audio decoding processing (S140), and temporarily stores it in the storage unit 32 as uncompressed audio data.
The playback device 30 resamples the audio data in the storage unit 32 in accordance with the playback speed and the audio sampling frequency of the HD-SDI output (S150).

  The playback device 30 transfers the resampled audio data to the temporary storage area of the video / audio output interface 31 (S160), and sends it from the playback device 30 to the playback environment 50 (S170).

  The playback device 30 makes a data request to the proxy storage server 20 based on the designated playback position, the determined use voice data, and requested data amount information, and receives the voice data via the network 60 (S200). .

When the audio data is compressed data, the playback device 30 performs proxy audio decoding processing (S210) and temporarily stores it in the storage unit 32 as uncompressed audio data.
The playback device 30 resamples the audio data in the storage unit 32 in accordance with the playback speed and the audio sampling frequency of the HD-SDI output (S220), and proceeds to the process of S160.

In the above-described embodiment, the HD storage server 10 and the proxy storage server 20 are described as separate servers. However, a single storage server having the functions of the HD storage server 10 and the proxy storage server 20 may be used.
Further, in the above-described embodiment, when the playback speed is 3 times or less, the audio data stored in the HD storage server 10 is acquired and played back. The playback speed is not limited to three times, and may be arbitrary.

From the above, it is possible to realize audio output without degrading the reproduction quality even when the reproduction apparatus performs high-speed double-speed reproduction.
In addition, when the playback device is limited to the use of the audio of the HD material, the audio data is required according to the speed of the double speed reproduction. However, since the audio of the proxy material is used, the capacity of the necessary audio data is larger than that of the audio of the HD material. The proxy ratio is reduced by the audio ratio, and the load on the server and network can be reduced accordingly.

  Even in a video server system adopting the TS format or the PS format, the playback apparatus can realize audio output at the time of double speed playback by acquiring relatively small proxy material data.

  The double-speed playback sound of the playback device is generally realized by thinning out samples of the original sound by allowing a slight change in pitch due to a change in playback speed. Therefore, for example, even if the original sound is not of a high-density HD material with a sampling frequency, but is of a low-density proxy material with a relatively low sampling frequency, an audio sample with a playback speed above a certain level. Therefore, the audio that is finally reproduced and output has the same ratio of thinned samples as compared with the original audio, so that the reproduction quality at the time of double-speed reproduction is not impaired.

  Although the present invention has been described in detail above, it is needless to say that the present invention is not limited to the video server system described herein and can be widely applied to video server systems other than those described above.

  10: HD storage server, 20: proxy storage server, 30: playback device, 40: control device, 50: playback environment unit, 100: video server system.

Claims (3)

In a video server system having an HD storage server that stores high-quality material data, a proxy storage server that stores low-quality material data, and a playback device,
The video server system, wherein the playback device acquires audio data from the HD storage server or the proxy storage server according to a playback speed. In an audio playback method for a video server system having an HD storage server for storing high-quality material data, a proxy storage server for storing low-quality material data, and a playback device,
A step of inputting a playback speed, a step of acquiring audio data from the HD storage server or the proxy storage server according to the playback speed, and a step of reproducing the audio data according to the playback speed. A featured audio playback method. The audio reproduction method according to claim 2,
An audio reproduction method characterized in that audio data is acquired from the HD storage server when the reproduction speed input in the step of inputting the reproduction speed is three times or less.

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