A first embodiment of the present invention is a multimedia playback system 1 as shown in
When the user inputs a playback instruction via the input device 11, the memory controller 121 reads a multimedia data 102 from the optical disc device 13 and transmits it to the FIFO memory 125 for buffering. The multimedia data 102 may comprise audio, video, subtitle, still image, navigation data and/or texture data. Some of these data should be synchronous during playback. For example, the audio and video data require synchronization; otherwise, the sound and display during playback would not match each other. The audio data and the video data are used hereinafter for illustration.
The decoder 14 further comprises a first decoder for decoding the video data and a second decoder for decoding the audio data. For the VCD format, the bit rate of the video data is 1150 kbps (kilo bits per second) and the bit rate of the audio data is 224 kbps. For the SVCD format, the bit rate of the video data ranges from 1700-2000 kbps on average, with a maximum of 2600 kbps. The bit rate of the audio data ranges from 32-384 kbps. For the DVD format, the bit rate of the video data can reach up to 9800 kbps in the MPEG2 and 1856 kbps in the MPEG1, with the bit rate of the audio data ranging from 32-1536 kbps. For the DIVX format, the bit rate of the video data is 4000 kbps on average and 8000 kbps at maximum, with the bit rate of the audio data ranging from 8-384 kbps in the MPEG 1 Layer 2 and from 32-640 kbps in the AC3.
The memory controller 121 then allocates the FIFO memory 125 for buffering the audio data 104 and the video data 106 according to the allocation information. The memory controller 121 manages the FIFO mechanism by controlling a read and write pointer during access to the FIFO memory 125. The allocation information depends on the throughput rates, e.g., the bit rates of the audio data 104 and the video data 106. As mentioned above, the bit rates vary in terms of disc formats. In the first embodiment, two allocation ways are provided. One is to set a constant ratio between the FIFO memory 125 space for buffering the video data 106 and the audio data 104 if the allocation information indicates a constant ratio between the bit rates of the video data 106 and the audio data 104 for most of the time. For example, the memory controller 121 would allocate the FIFO memory 125 space for buffering the video data 106 and the audio data 104 at 1150:224 if the disc is a VCD. The ratio can be derived from a table which is established in advance.
The other way is to set a variable ratio in terms of time for buffering the video data 106 and the audio data 104 in the FIFO memory 125 space if the allocation information indicates a variable ratio between the bit rates of the video data 106 and the audio data 104. For example, the memory controller 121 allocates a variable FIFO memory 125 space for buffering the video data 106 and the audio data 104 if the disc is a SVCD, DVD, or DIVX. More specifically, the allocation ratio of the FIFO memory 125 space may be determined according to the video data 106 and the audio data 104 as a whole or partially. That is, the allocation ratio is calculated by averaging the data 104, 106 in whole or in part. For example, if the disc is a DVD, partial consideration would include one title of the DVD. Thus, the varying allocation ratios can be used to allocate the FIFO memory 125, providing a more precise adjustment against the shock effect.
When the video data 106 and the audio data 104 are about to be played, the video data 106 is transmitted from the FIFO memory 125 to the decoder 14 for decoding. After decoding, decoded video data 108 is generated. The decoded video data 108 is transmitted to the display 15. Similarly, the audio data 104 is transmitted from the FIFO memory 125 to the decoder 14 for decoding. After decoding, a decoded audio data 110 is generated. The decoded audio data 110 is transmitted to the speaker 16. Since the FIFO memory 125 space for buffering the video data 106 and the audio data 104 is allocated based on their throughput rates, the outputs of the display 15 and the speaker 16 may be synchronized even if a shock occurs.
A second embodiment of the present invention is a method for storing audio and video data. The second embodiment is adapted for any multimedia playback system, such as the illustrated multimedia playback system 1.
In addition to the steps shown in
A third embodiment of the present invention is also a method for storing audio and video data in a FIFO memory. The third embodiment is adapted for a multimedia playback system, such as the illustrated multimedia playback system 1. In the third embodiment, the audio and video data are separated into several sections, with each section comprising a title if the disc is a DVD disc or comprising a track if the disc is a VCD or SVCD disc.
The section comprises at least one title or track. During playback flow, if the multimedia player finishes playing this section and continues to play a next section, the FIFO memory can be freed and all the buffered multimedia data in the FIFO memory can be cleaned. A portion of the multimedia data meeting the aforementioned rule is defined as a section. If the next section is chosen to be played, corresponding section allocation information would be used for allocating the FIFO memory before playing.
In addition to the steps shown in
A fourth embodiment of the present invention is another method for processing multimedia data stored on a DVD disc. The multimedia data is separated into several sections, with each section comprising a title.
In addition to the steps shown in
A fifth embodiment of the present invention is another method for processing multimedia data stored in a DIVX format.
In addition to the steps shown in
The present invention is capable of allocating the FIFO memory of different multimedia data according to the throughput rates of the multimedia data. The problem of discontinuous playback due to, for example, shock, can be solved thereby.
The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.