Video/audio playback apparatus and video/audio playback method

• US 20050185923A1
• Filed: 02/24/2005
• Published: 08/25/2005
• Est. Priority Date: 02/25/2004
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ohiro, Toshihisa, Uemura, Takami, Hida, Yoichi, Tsurui, Taisuke
• Granted Patent: US 7,266,288 B2
• Time in Patent Office: Days
• US Class Current: 386/248
• CPC Class Codes: G11B 27/005 Reproducing at a different information rate from the information rate of recording for television signals H04N5/783
• CPC Class Codes: G11B 27/3036 Time code signal
• CPC Class Codes: H04N 5/781 on disks or drums
• CPC Class Codes: H04N 5/783 Adaptations for reproducing at a rate different from the recording rate
• CPC Class Codes: H04N 5/85 on discs or drums
• CPC Class Codes: H04N 5/907 using static stores, e.g. storage tubes or semiconductor memories H04N5/91 takes precedence
• CPC Class Codes: H04N 9/8042 involving data reduction
• CPC Class Codes: H04N 9/8063 using time division multiplex of the PCM audio and PCM video signals

Abstract

Provided is a video/audio playback apparatus and a video/audio playback method in which on receiving an instruction for switching video operation from the video operation switching circuit, a data reading circuit reads a video/audio stream for playing an audio and a video/audio stream for playing a video from a recording medium, and an audio playback circuit reproduces an audio stream separated from the video/audio stream for playing the audio on the basis of time management information embedded in the audio stream and a predetermined reference time, and a video playback circuit reproduces a video stream separated from the video/audio stream for playing the video on the basis of a reference time different from the reference time, and thereby the video can freely played with the audio being normally played.

Claims

1. A video/audio playback apparatus which reads a video/audio stream recorded in a random accessible recording medium, and reproduces the video/audio stream on the basis of a reference time and time management information which is embedded in each of a video stream and an audio stream which constitute the video/audio stream, comprising:

a video operation switching circuit for indicating that a playback operation of the video stream is to be switched;

a data reading circuit for reading a video/audio stream for playing an audio and a video/audio stream for playing a video from the recording medium on receiving the instruction for switching the video operation from the video operation switching circuit;

a stream buffer for distinguishably storing the video/audio stream for playing audio and the video/audio stream for playing video which are read by the data reading circuit;

a separation circuit for separating an audio stream and a video stream from the video/audio stream for playing audio and the video/audio stream for playing video, which are stored in the stream buffer, respectively;

a counter for outputting a predetermined clock as a reference time on the basis of the time management information embedded in the video/audio stream for playing audio;

an audio playback circuit for reproducing the audio stream separated from the video/audio stream for playing audio on the basis of the time management information embedded in the audio stream and the reference time; and

a video playback circuit for reproducing the video stream separated from the video/audio stream for playing video on the basis of a reference time different from that for the audio playback circuit.

2. The video/audio playback apparatus as defined in claim 1, wherein

the video/audio stream is a stream into which the digital-compressed video and audio are multiplexed according to the MPEG format.

3. The video/audio playback apparatus as defined in claim 1, wherein

the video operation switching circuit gives instructions for switching among normal playback for synchronously reproducing an audio stream and a video stream having the same time management information, video trick play for performing trick play of only a video stream, and video asynchronous playback for asynchronously reproducing an audio stream and a video stream each having time management information.

4. The video/audio playback apparatus as defined in claim 3, wherein

the video playback circuit performs trick play of the video stream by using the video stream separated from the video/audio stream for playing video on receiving the instruction for the video trick play operation from the video operation switching circuit.

5. The video/audio playback apparatus as defined in claim 4, wherein

the data reading circuit reads video/audio streams for playing audios with higher priority than video/audio streams for playing videos are read, and continuously transmits the audio streams to the audio playback circuit so as not to interrupt audios which are to be played by the audio playback circuit when receiving the instruction for the video trick play operation from the video operation switching circuit.

6. The video/audio playback apparatus as defined in claim 5, wherein

the video playback circuit reproduces the video stream separated from the video/audio stream for playing video with using a value obtained by subtracting, from the reference time, a differential value between the time management information embedded in the video stream which was outputted most recently at the video trick play and the reference time as of the time at which the video trick play is stopped, as a reference time for reading the video stream, when receiving the instruction for performing the video asynchronous playback halfway through the video trick play from the video operation switching circuit.

7. The video/audio playback apparatus as defined in claim 6, wherein

the video playback circuit reproduces the video stream separated from the video/audio stream for playing audio on the basis of the time management information embedded in the video stream and the reference time when receiving the instruction for performing the normal playback operation halfway through the video asynchronous playback operation from the video operation switching circuit.

8. The video/audio playback apparatus as defined in claim 4, wherein

the video playback circuit reproduces the video stream of the video/audio stream for playing audio on the basis of the time management information embedded in the video stream and the reference time when the time management information embedded in the video stream which is being subjected to video trick play coincides with the reference time.

9. The video/audio playback apparatus as defined in claim 7, comprising

a playback time display circuit for visually displaying one of a playback time of the audio which is played by the audio playback circuit and a playback time of the video which is played by the video playback circuit, or both of them.

13. The video/audio playback apparatus as defined in claim 1, comprising

a display video control circuit for displaying a display video which was outputted immediately before an instruction for switching a video operation, on a sub-screen which is other than a main screen onto which the video stream is reproduced, when receiving the instruction for switching the video operation from the video operation switching circuit.

14. The video/audio playback apparatus as defined in claim 13, wherein

the display video control circuit displays, when receiving an instruction for switching a video operation from the video operation switching circuit in a state where the videos are displayed on the main screen and the sub-screen, the display video which was outputted onto the main screen immediately before the instruction for switching the video operation is received, on a new sub-screen.

15. The video/audio playback apparatus as defined in claim 14, further comprising

a video operation selection circuit for selecting one of the sub-screens, wherein

the display video control circuit switches between a video display on the sub-screen selected by the video operation selection circuit and the video display on the main screen and displays the respective videos when receiving an instruction for switching a video operation from the video operation switching circuit, and

the video playback circuit reproduces a video stream so as to start playback from the switched display video on the main screen.

17. The video/audio playback apparatus as defined in claim 8, comprising

a playback time display circuit for visually displaying one of a playback time of the audio which is played by the audio playback circuit and a playback time of the video which is played by the video playback circuit, or both of them.

10. A video/audio playback method for reading a video/audio stream recorded in a random accessible recording medium, and reproducing the video/audio stream on the basis of time management information embedded in each of a video stream and an audio stream which constitute the video/audio stream and a predetermined reference time, comprising:

reading a video/audio stream for playing an audio and a video/audio stream for playing a video from the recording medium;

extracting a predetermined clock as a reference time on the basis of a predetermined time management information embedded in the video/audio stream for playing audio; and

reproducing an audio stream of the video/audio stream for playing audio on the basis of the time management information embedded in the audio stream and the reference time, and performing trick play of a video stream using the video/audio stream for playing video.

11. The video/audio playback method as defined in claim 10, comprising:

stopping trick play of the video stream;

obtaining a differential value between the time management information embedded in the video stream which was outputted most recently at the trick play of the video stream and the reference time as of the time at which the video trick play is stopped and subtracting the differential value from the reference time; and

reproducing the video stream separated from the video/audio stream for playing video with using the subtraction value as a reference time for reproducing video stream.

12. The video/audio playback method as defined in claim 10, comprising

reproducing the video stream of the video/audio stream for playing audio on the basis of the time management information embedded in the video stream and the reference time when the time management information embedded in the video stream displayed at the trick play of the video stream coincides with the reference time.

16. The video/audio playback method as defined in claim 10, comprising

performing the trick play of the video stream with the display video from which the trick play is started being displayed on another screen when performing the trick play of the video stream.