摘要:
An audiovisual encoding system using a multipass video encoder (50) and a plurality of one-pass audio encoders (70a, 70b, 70c and 70d). The number of audio encoders used by the system is equal to the number of audio tracks to be encoded divided by the number of passes required for the video encoding rounded up to the nearest integer, if necessary. The system allows the video encoder (50) and audio encoders (70a, 70b, 70c and 70d) to be used at the same time so that the encoding of the video is completed at the same time as the encoding of all audio tracks is completed, using the minimum number of audio encoders (70a, 70b, 70c and 70d).
摘要:
A method and system for re-encoding frames of a digital video stream without changing the previously calculated bit length of the stream. A set of macroblocks at a time are re-encoded (292), the number of resulting bits is calculated (306, 368) and the deviation from an estimated number of bits is calculated (372), either set-by-set or cumulatively. Based on the accuracy (372), of the estimate (422) and the remaining number of sets of macroblocks (424) to re-encode, a correction factor (710) for the quantization level of the next set of macroblocks is chosen from a lookup table. The correction factor is added to the quantization level of the next set of macroblocks (712) and the results stored as the new quantization level of the set (706). This sequential process is done for all sets of macroblocks in the digital stream which are to be recorded according to changed image qualities (706, 708, 710, 712, 714).
摘要:
A method and system in which a user manually changes the quality of portions of video frames after the frames have been previously encoded. Regions of one or more frames of video are selected to have an increased quality, a decreased quality, or a quality which should not be altered. After the regions are defined by a user, the frame of video is digitally re-encoded and inserted into the digitally encoded data stream in place of the previously encoded data. In order to easily remove a previously encoded frame from the data steam and replace it with a newly encoded frame having regions of quality defined by the user, it is preferable to have the newly encoded frame consume the same number of bits as the previously encoded frame. Accordingly, if the user desires a region of a frame to have an increased quality, the extra bits necessary to provide the increased quality must be taken from other areas of the frame. This is accomplished by an automatic process which is transparent to the user. Additionally, if the user wants to change the quality of an object for a series of video frames, the user can mark a region in a first frame and a corresponding region in a last frame and the system will automatically adjust the quality of the region as the region moves through the series of video frames.
摘要:
A system (31, 41, 32, 33) in which a user manually changes the quality of specific time periods of encoded video (180). After the automatic encoding (50) of video into a compressed digital format, a person editing (31, 33) the encoded video reviews the quality of the video and manually indicates that the quality of specific time periods (180) of the video is to be altered. As the digital storage medium such as an optical disc (84, 90) which stores the encoded video has finite storage capacity, the total number of bits for the encoded video (50) and the quality of the video is limited. A percentage of bits are removed from time sequence and placed in a bit pool (368). Using an exponential function (368) new bits are calculated and the bits in the bit pool are proportionally distributed to the video frames (376). The frames must then be checked (394) and possibly adjusted (398, 400) to prevent underflow of the video buffer.
摘要:
A system and method for determining quantization level versus bit-rate characteristics of raw video signals in video frames during a pre-encoding phase for video technologies such as MPEG and MPEG-2. During a pre-encoding phase, various quantization levels are assigned to various parts of a frame, and the frame is then pre-encoded to determine a bit-rate for each quantization level used in the pre-encoding phase. Depending on the embodiment, quantization levels are assigned in one of many ways: checkerboard style, block style or any other distribution that avoids statistical anomalies. The method and system repeat the pre-encoding for plural frames, recording all quantization level versus bit-rate statistics on a frame by frame basis. These statistics are then used during encoding or re-encoding of a digital video to control the number of bits allocated to one segment of the digital video as compared to another segment, based on a target quality and target storage size for each segment. The resulting encoded digital video is stored on a digital storage medium, such as a compact disc.