Picture editing apparatus and method using virtual buffer estimation

• US 6,137,946 A
• Filed: 04/03/1998
• Issued: 10/24/2000
• Est. Priority Date: 04/04/1997
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ando, Yuji
• Primary Examiner(s): NGUYEN, HUY THANH
• Application Number:
  US09/054,858
• Time in Patent Office: 935 Days
• Field of Search: 386/46, 386/52, 386/95, 386/96, 386/98, 386/111, 386/112, 348/584, 348/473, 370/487
• US Class Current: 386/283
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 2220/218 Write-once discs
• CPC Class Codes: G11B 2220/2545 CDs
• CPC Class Codes: G11B 27/034 on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/23611 Insertion of stuffing data into a multiplex stream, e.g. to obtain a constant bitrate synchronisation arrangements in time-division multiplex systems using bit stuffing for systems with different or fluctuating information rates H04J3/073
• CPC Class Codes: H04N 21/2401 Monitoring of the client buffer
• CPC Class Codes: H04N 5/765 Interface circuits between an apparatus for recording and another apparatus
• CPC Class Codes: H04N 5/77 between a recording apparatus and a television camera
• CPC Class Codes: H04N 5/775 between a recording apparatus and a television receiver

Abstract

A bit stream C is composed in editing work at a high processing speed wherein at least a portion of a bit stream A resulting from MPEG encoding is concatenated with at least a portion of a bit stream B also resulting from MPEG encoding. The amount of data D_A at an end point A_out of a scene A'"'"' of the bit stream A and the amount of data D_B at a start point B_in of a scene B'"'"' of the bit stream B to be accumulated in a VBV buffer are calculated. The difference between D_A and D_B is used for adjusting the amount of data at a portion of the bit stream C which corresponds to a point of junction between the bit streams A and B. If D_A >D_B, stuffing code is added to a picture at the end point A_out. If D_A <D_B, on the other hand, skipped P pictures are inserted into a location after the picture at the end point A_out.

Claims

1. A picture editing apparatus for concatenating at least a portion of a first bit stream obtained as a result of an operation to compress and encode pictures with at least a portion of a second bit stream also obtained as a result of said operation to compress and encode pictures, thereby composing a third bit stream through editing said first and second bit streams, wherein said operation to compress and encode pictures is carried out by considering an amount of data to be accumulated in a virtual buffer on a receiving side, and wherein accumulation quantity information on said amount of data to be accumulated is included in said first and second bit streams. said picture editing apparatus comprising:

data accumulation quantity computing means for computing an amount of data to be accumulated in said virtual buffer at a first point of junction on said first bit stream for connecting said first bit stream to said second bit stream and for computing an amount of data to be accumulated in said virtual buffer at a second point of junction on said second bit stream for connecting said second bit stream to said first bit stream by using said accumulation quantity information; and

data quantity adjusting means for adjusting an amount of data at a portion of said third bit stream corresponding to a point of junction between said first and second bit streams in accordance with a difference between said amounts of data to be accumulated in said virtual buffer at said first and second points of junction computed by said data accumulation quantity computing means,

wherein said first and second bit streams are each a result of said operation to compress and encode pictures at least conforming to MPEG (Moving Picture Expert Group) specifications,

wherein said accumulation quantity information is a VD (Video Buffering Verifier Delay) which is included in a picture header and corresponds to said amount of data to be accumulated,

wherein said virtual buffer is a VBV (Video Buffering Verifier) buffer, and

wherein said data quantity adjusting means inserts data of a skipped P picture to a location following data of a picture at said first point of junction if said amount of data to be accumulated in said VBV buffer at said first point of junction is smaller than said amount of data to be accumulated in said VBV buffer at said second point of junction.

2. A picture editing apparatus according to claim 1 wherein:

said data quantity adjusting means inserts a stuffing code into data of a picture at said first point of junction if said amount of data to be accumulated in said VBV buffer at said first point of junction is greater than said amount of data to be accumulated in said VBV buffer at said second point of junction.

3. A picture editing apparatus according to claim 2 wherein:

said data quantity adjusting means inserts said stuffing code into data of said picture at said first point of junction so that said amounts of data to be accumulated in said VBV buffer at said first and second points of junction become equal to each other.

4. A picture editing apparatus according to claim 1 wherein:

said data quantity adjusting means inserts said data of said skipped P picture so that said amount of data to be accumulated in said VBV buffer at said first point of junction after insertion of said data of said skipped P picture becomes equal to or greater than said amount of data to be accumulated in said VBV buffer at said second point of junction.

5. A picture editing apparatus according to claim 4 wherein:

if said amount of data to be accumulated in said VBV buffer at said first point of junction after insertion of said data of said skipped P picture becomes greater than said amount of data to be accumulated in said VBV buffer at said second point of junction, a stuffing code is inserted so that said amounts of data to be accumulated in said VBV buffer at said first and second points of junction become equal to each other.

6. A picture editing apparatus according to claim 1, further comprising:

bit rate inferring means for inferring bit rates of said first and second bit streams;

wherein said data accumulation quantity computing means computes said amount of data to be accumulated in said VBV buffer from said bit rates inferred by said bit rate inferring means and said accumulation quantity information.

7. A picture editing method of concatenating at least a portion of a first bit stream obtained as a result of an operation to compress and encode pictures with at least a portion of a second bit stream also obtained as a result of said operation to compress and encode pictures, thereby composing a third bit stream through editing said first and second bit streams, wherein said operation to compress and encode pictures is carried out by considering an amount of data to be accumulated in a virtual buffer on a receiving side, and wherein accumulation quantity information on said amount of data to be accumulated in said virtual buffer is included in said first and second bit streams, said picture editing method comprising the steps of:

computing an amount of data to be accumulated in said virtual buffer at a first point of junction on said first bit stream for connecting said first bit stream to said second bit stream and computing an amount of data to be accumulated in said virtual buffer at a second point of junction on said second bit stream for connecting said second bit stream to said first bit stream by using said accumulation quantity information; and

adjusting an amount of data at a portion of said third bit stream corresponding to a point of junction between said first and second bit streams in accordance with a difference between said amounts of data to be accumulated in said virtual buffer at said first and second points of junction,

wherein said first and second bit streams are each a result of said operation to compress and encode pictures at least conforming to MPEG (Moving Picture Expert Group) specifications,

wherein said accumulation quantity information is a VD (Video Buffering Verifier Delay) which is included in a picture header and corresponds to said amount of data to be accumulated,

wherein said virtual buffer is a VBV (Video Buffering Verifier) buffer, and

wherein said step of adjusting comprises inserting data of skipped P picture to a location following data of a picture at said first point of junction if said amount of data to be accumulated in said VBV buffer at said first point of junction is smaller than said amount of data to be accumulate in said VBV buffer at said second point of junction.