Video-Previewing Methods and Systems for Providing Preview of a Video and Machine-Readable Storage Mediums Thereof

1. A video-previewing method for providing preview of a video to be played for an electronic device with a touch-sensitive display unit, the method comprising: detecting a resolution of the touch-sensitive display unit of the electronic device; and generating a preview screen corresponding to the video on the touch-sensitive display unit according to the resolution of the touch-sensitive display unit, wherein the preview screen includes M level frame bars and each of the M level frame bars displays N video frames, wherein a frame number N is a value representing a number of video frames for each of the M level frame bars determined based on the resolution of the touch-sensitive display unit and a level number M is a value representing a number of levels determined according to a video length of the video, where M>1 and N≧1, wherein the video length is a total time length of the video to be played, wherein the method further comprises: providing first, second and third parameters; determining a maximum value of the N according to the resolution of the touch-sensitive display unit and the first parameter; and determining the value of the level number M according to the video length of the video, the second parameter and the third parameter, wherein the first parameter represents an expected resolution, the second parameter represents a minimum expected gap between each two of the N video frames and the third parameter represents a maximum expected gap between each two of the N video frames; wherein the step of determining the value of the level number M according to the video length of the video, the second parameter and the third parameters further comprises: obtaining a first count value according to the video length of the video and the second parameter and determining whether the first count value has exceeded the maximum value of the frame number N; when the first count value has exceeded the maximum value of the frame number N, obtaining a second count value according to the video length of the video and the third parameter and determining whether the second count value has exceeded the maximum value of the frame number N; and when the second count value has exceeded the maximum value of the frame number N, determining the value of the level number M is set to be at least 2 and setting the value of the frame number N for a first level frame bar among the M level frame bars to the maximum value of the frame number N; and wherein the method further comprises: dividing the video into the N video frames based on the video length of the video; and obtaining a third count value according to a frame length of each of the N frames and the second parameter and determining whether the third count value has exceeded the maximum value of the frame number N; when the third count value has not exceeded the maximum value of the frame number N, determining the value of the level number M is set to be 2 and setting the value of the frame number N for a second level frame bar among the M level frame bars to the third count value; when the third count value has exceeded the maximum value of the frame number N, obtaining a fourth count value according to the video length of the video and the third parameter and determining whether the fourth count value has exceeded the maximum value of the frame number N; and when the fourth count value has not exceeded the maximum value of the frame number N, determining the value of the level number M is set to be 2 and setting the value of the frame number N for the second level frame bar among the M level frame bars N to the fourth count value.

2. The video-previewing method of claim 1 , wherein the maximum value of the level number M is set to be 3.

3. The video-previewing method of claim 1 , further comprising: when the fourth count value has exceeded the maximum value of the frame number N, determining the value of the level number M is set to be 3 and setting the value of the frame number N for the second level frame bar among the M level frame bars to the maximum value of the frame number N.

4. The video-previewing method of claim 3 , further comprising: dividing the video frame into N sub-frames based on the video length of the video; and obtaining a fifth count value according to a sub-frame length of each of the N sub-frames and the second parameter and determining whether the fifth count value has exceeded the maximum value of the frame number N; when the fifth count value has not exceeded the maximum value of the frame number N, determining the value of the level number M is set to be 3 and setting the value of the frame number N for a third level frame bar among the M level frame bars to the fifth count value; when the fifth count value has exceeded the maximum value of the frame number N, obtaining a sixth count value according to the sub-frame length and the third parameter and determining whether the sixth count value has exceeded the maximum value of the frame number N; and when the sixth count value has not exceeded the maximum value of the frame number N, determining the value of the level number M is set to be 3 and setting the value of the frame number N for the third level frame bar among the M level frame bars to the sixth count value.

5. The video-previewing method of claim 4 , further comprising: when determining that the value of the level number M is set to be 3, determining the value of the frame number N for the third level frame bar among the M level frame bars according to an unconditional cutting or an unconditional rounding-up method.

6. A video-previewing system for providing preview of a video to be played, the system comprising: a touch-sensitive display unit, having a resolution; a parameter generation unit, detecting the resolution of the touch-sensitive display unit; and a preview screen generation unit coupled to the parameter generation unit and the touch-sensitive display unit, generating a preview screen corresponding to the video on the touch-sensitive display unit according to the resolution of the touch-sensitive display unit detected by the parameter generation unit, wherein the preview screen includes M level frame bars and each of the M level frame bars displays N video frames; wherein a frame number N is a value representing a number of video frames for each of the M level frame bars determined based on the resolution of the touch-sensitive display unit, and a level number M is a value representing a number of levels determined according to a video length of the video detected by the parameter generation unit, where M>1 and N≧1, wherein the video length is a total time length of the video to be played; wherein the parameter generation unit further provides first, second and third parameters and the preview screen generation unit further determines a maximum value of the N according to the resolution of the touch-sensitive display unit and the first parameter; and determines the value of the level number M according to the video length of the video, the second parameter and the third parameter, wherein the first parameter represents an expected resolution, the second parameter represents a minimum expected gap between each two of the N video frames and the third parameter represents a maximum expected gap between each two of the N video frames; wherein the preview screen generation unit further obtains a first count value according to the video length of the video and the second parameter and determines whether the first count value has exceeded the maximum value of the frame number N preview screen generation unit, wherein when the first count value has exceeded the maximum value of the frame number N, the preview screen generation unit further obtains a second count value according to the video length of the video and the third parameter and determines whether the second count value has exceeded the maximum value of the frame number N and determines the value of the level number M is set to be at least 2 and sets the value of the frame number N for a first level frame bar among the M level frame bars to the maximum value of the frame number N when the second count value has exceeded the maximum value of the frame number N; wherein the preview screen generation unit further divides the video into the N video frames based on the video length of the video, obtains a third count value according to a frame length of each of the N frames and the second parameter and determines whether the third count value has exceeded the maximum value of the frame number N; wherein when the third count value has not exceeded the maximum value of the frame number N, the preview screen generation unit determines the value of the level number M is set to be 2 and sets the value of the frame number N for a second level frame bar among the M level frame bars to the third count value; when the third count value has exceeded the maximum value of the frame number N, the preview screen generation unit obtains a fourth count value according to the video length of the video and the third parameter and determines whether the fourth count value has exceeded the maximum value of the frame number N; and when the fourth count value has not exceeded the maximum value of the frame number N, the preview screen generation unit further determines the value of the level number M is set to be 2 and sets the value of the frame number N for the second level frame bar among the M level frame bars to the fourth count value.

7. The video-previewing system of claim 6 , wherein the maximum value of the level number M is set to be 3.

8. The video-previewing system of claim 6 , wherein the preview screen generation unit further determines the value of the level number M is set to be 3 and sets the value of the frame number N for the second level frame bar among the M level frame bars to the maximum value of the frame number N when the fourth count value has exceeded the maximum value of the frame number N.

9. The video-previewing system of claim 8 , wherein the preview screen generation unit further divides the video frame into N sub-frames based on the video length of the video, obtains a fifth count value according to a sub-frame length of each of the N sub-frames and the second parameter and determines whether the fifth count value has exceeded the maximum value of the frame number N; wherein when the fifth count value has not exceeded the maximum value of the frame number N, the preview screen generation unit determines the value of the level number M is set to be 3 and sets the value of the frame number N for a third level frame bar among the M level frame bars to the fifth count value; when the fifth count value has exceeded the maximum value of the frame number N, the preview screen generation unit obtains a sixth count value according to the sub-frame length and the third parameter and determines whether the sixth count value has exceeded the maximum value of the frame number N; and when the sixth count value has not exceeded the maximum value of the frame number N, the preview screen generation unit further determines the value of the level number M is set to be 3 and setting the third level frame bar among the M level frame bars to the sixth count value; wherein the preview screen generation unit further determines the value of the frame number N for the third level frame bar among the M level frame bars according to an unconditional cutting or an unconditional rounding-up method when determining that the value of the level number M is set to be 3.

10. A non-transitory machine-readable storage medium comprising a computer program, which means for driving a device to perform a video-previewing method for providing preview of a video to be played, wherein the device includes a touch-sensitive display unit and the video-previewing method comprises the steps of: detecting a resolution of the touch-sensitive display unit; and generating a preview screen corresponding to the video on the touch-sensitive display unit according to the resolution of the touch-sensitive display unit detected by the parameter generation unit, wherein the preview screen includes M level frame bars and each of the M level frame bars displays N video frames, wherein a frame number N is a value representing a number of video frames for each of the M level frame bars determined based on the resolution of the touch-sensitive display unit, and a level number M is a value representing a number of levels determined according to a video length of the video, where M>1 and N≧1, wherein the video length is a total time length of the video to be played, wherein the method further comprises: providing first, second and third parameters; determining a maximum value of the N according to the resolution of the touch-sensitive display unit and the first parameter; and determining the value of the level number M according to the video length of the video, the second parameter and the third parameter, wherein the first parameter represents an expected resolution, the second parameter represents a minimum expected gap between each two of the N video frames and the third parameter represents a maximum expected gap between each two of the N video frames, wherein the step of determining the value of the level number M according to the video length of the video, the second parameter and the third parameters further comprises: obtaining a first count value according to the video length of the video and the second parameter and determining whether the first count value has exceeded the maximum value of the frame number N; when the first count value has exceeded the maximum value of the frame number N, obtaining a second count value according to the video length of the video and the third parameter and determining whether the second count value has exceeded the maximum value of the frame number N; and when the second count value has exceeded the maximum value of the frame number N, determining the value of the level number M is set to be at least 2 and setting the value of the frame number N for a first level frame bar among the M level frame bars to the maximum value of the frame number N; and wherein the method further comprises: dividing the video into the N video frames based on the video length of the video; and obtaining a third count value according to a frame length of each of the N frames and the second parameter and determining whether the third count value has exceeded the maximum value of the frame number N; when the third count value has not exceeded the maximum value of the frame number N, determining the value of the level number M is set to be 2 and setting the value of the frame number N for a second level frame bar among the M level frame bars to the third count value; when the third count value has exceeded the maximum value of the frame number N, obtaining a fourth count value according to the video length of the video and the third parameter and determining whether the fourth count value has exceeded the maximum value of the frame number N; and when the fourth count value has not exceeded the maximum value of the frame number N, determining the value of the level number M is set to be 2 and setting the value of the frame number N for the second level frame bar among the M level frame bars N to the fourth count value.