Body: <p>I have video shot using a Sony PXW-Z280V using AVC_3840_2160_HP@L51 with 29.97 frame rate. Upon analyzing the MXF file structure, I notice that the Index Entry Array seems incorrect. In particular the KeyFrameOffset values for the first two B-frames in every GOP points back two prior I-frames. But that doesn't make any sense, since the previous I-frame has all the information needed, so why go back to the one before that?</p>
  <p>See the following entries (especially #16, #17). To me it looks like the frame offset values for these two frames should be -1, -2 instead of -16, -17. Is this a problem with the Sony codec implementation, or something I'm not understanding correctly?</p>
  <pre><code>              #  TempOffs  KeyOffs                 Flags       StreamOffs  Sl.Offs# 0
                0         1        0    0xC4 R S . . . 1 I   0x000000000000     2357760
                1         1       -1    0x13 . . . Bp. . B   0x000000244E00      162816
                2        -2       -2    0x13 . . . Bp. . B   0x000000271E00      278528
                3         1       -3    0x22 . . Fp. . . P   0x0000002BB200      488448
                4         1       -4    0x33 . . FpBp. . B   0x000000337A00      211456
                5        -2       -5    0x33 . . FpBp. . B   0x000000370800      297472
                6         1       -6    0x22 . . Fp. . . P   0x0000003BE600      553984
                7         1       -7    0x33 . . FpBp. . B   0x00000044AE00      315392
                8        -2       -8    0x33 . . FpBp. . B   0x00000049D200      293888
                9         1       -9    0x22 . . Fp. . . P   0x0000004EA200      612864
               10         1      -10    0x33 . . FpBp. . B   0x000000585000      305152
               11        -2      -11    0x33 . . FpBp. . B   0x0000005D4C00      306688
               12         1      -12    0x22 . . Fp. . . P   0x000000624E00      585216
               13         1      -13    0x33 . . FpBp. . B   0x0000006B9000      316928
               14        -2      -14    0x33 . . FpBp. . B   0x00000070BA00      299008
               15         1        0    0x40 . S . . . . I   0x000000759E00      582656
               16         1      -16    0x33 . . FpBp. . B   0x0000007ED600      302080
               17        -2      -17    0x33 . . FpBp. . B   0x00000083C600      236032
               18         1       -3    0x22 . . Fp. . . P   0x00000087B400      650240
               19         1       -4    0x33 . . FpBp. . B   0x00000091F400      246784
               20        -2       -5    0x33 . . FpBp. . B   0x000000960C00      252416
               21         1       -6    0x22 . . Fp. . . P   0x0000009A3A00      649216
               22         1       -7    0x33 . . FpBp. . B   0x000000A47600      251904
               23        -2       -8    0x33 . . FpBp. . B   0x000000A8A200      249856
               24         1       -9    0x22 . . Fp. . . P   0x000000ACC600      649216
               25         1      -10    0x33 . . FpBp. . B   0x000000B70200      252928
               26        -2      -11    0x33 . . FpBp. . B   0x000000BB3200      250368
               27         1      -12    0x22 . . Fp. . . P   0x000000BF5800      643584
               28         1      -13    0x33 . . FpBp. . B   0x000000C97E00      249856
               29        -2      -14    0x33 . . FpBp. . B   0x000000CDA200      247808
               30         1        0    0x40 . S . . . . I   0x000000D1BE00      951808
               31         1      -16    0x33 . . FpBp. . B   0x000000E09800      246272
               32        -2      -17    0x33 . . FpBp. . B   0x000000E4AE00      235520
               33         1       -3    0x22 . . Fp. . . P   0x000000E89A00      663552
               34         1       -4    0x33 . . FpBp. . B   0x000000F30E00      239104
              
  </code></pre>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-07-28T00:19:46.047Z
Comments.Text: Welcome! Are you having problems playing or working with the files or are you going through validation testing? Have you asked Sony about this? They tend to have their own interpretation of some of the standards.
Comments.UserDisplayName: Michael Liebman
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-07-28T05:15:16.593Z
Comments.Text: I'm trying to implement partial file restore from tape (the essence rewrapping part). My files are importable in FCP, Premiere Pro, but not Resolve. When I ran the file through some validation tools, I came across this issue. I don't know who to contact in Sony about this.
Comments.UserDisplayName: swami
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-07-28T15:32:50.207Z
Comments.Text: If you are an end user, I'd start with sales or support. If you are vendor, you probably need to work through who ever handles channel partners. If you don't know who that is, and you are working with a specific client, I'd ask them to make the introduction.
Comments.UserDisplayName: Michael Liebman
Tags: <video><encoding><sony><gop>
Title: Sony PXW-Z280V AVC strange Long GOP pattern
UserDisplayName: swami
ThreadText: # Sony PXW-Z280V AVC strange Long GOP pattern
  
  (Asked by: username_0 on 2022-07-27)
  
  I have video shot using a Sony PXW-Z280V using AVC\_3840\_2160\_HP@L51 with 29.97 frame rate. Upon analyzing the MXF file structure, I notice that the Index Entry Array seems incorrect. In particular the KeyFrameOffset values for the first two B-frames in every GOP points back two prior I-frames. But that doesn't make any sense, since the previous I-frame has all the information needed, so why go back to the one before that?
  
  See the following entries (especially #16, #17). To me it looks like the frame offset values for these two frames should be -1, -2 instead of -16, -17. Is this a problem with the Sony codec implementation, or something I'm not understanding correctly?
  
  ```
                #  TempOffs  KeyOffs                 Flags       StreamOffs  Sl.Offs# 0
                0         1        0    0xC4 R S . . . 1 I   0x000000000000     2357760
                1         1       -1    0x13 . . . Bp. . B   0x000000244E00      162816
                2        -2       -2    0x13 . . . Bp. . B   0x000000271E00      278528
                3         1       -3    0x22 . . Fp. . . P   0x0000002BB200      488448
                4         1       -4    0x33 . . FpBp. . B   0x000000337A00      211456
                5        -2       -5    0x33 . . FpBp. . B   0x000000370800      297472
                6         1       -6    0x22 . . Fp. . . P   0x0000003BE600      553984
                7         1       -7    0x33 . . FpBp. . B   0x00000044AE00      315392
                8        -2       -8    0x33 . . FpBp. . B   0x00000049D200      293888
                9         1       -9    0x22 . . Fp. . . P   0x0000004EA200      612864
               10         1      -10    0x33 . . FpBp. . B   0x000000585000      305152
               11        -2      -11    0x33 . . FpBp. . B   0x0000005D4C00      306688
               12         1      -12    0x22 . . Fp. . . P   0x000000624E00      585216
               13         1      -13    0x33 . . FpBp. . B   0x0000006B9000      316928
               14        -2      -14    0x33 . . FpBp. . B   0x00000070BA00      299008
               15         1        0    0x40 . S . . . . I   0x000000759E00      582656
               16         1      -16    0x33 . . FpBp. . B   0x0000007ED600      302080
               17        -2      -17    0x33 . . FpBp. . B   0x00000083C600      236032
               18         1       -3    0x22 . . Fp. . . P   0x00000087B400      650240
               19         1       -4    0x33 . . FpBp. . B   0x00000091F400      246784
               20        -2       -5    0x33 . . FpBp. . B   0x000000960C00      252416
               21         1       -6    0x22 . . Fp. . . P   0x0000009A3A00      649216
               22         1       -7    0x33 . . FpBp. . B   0x000000A47600      251904
               23        -2       -8    0x33 . . FpBp. . B   0x000000A8A200      249856
               24         1       -9    0x22 . . Fp. . . P   0x000000ACC600      649216
               25         1      -10    0x33 . . FpBp. . B   0x000000B70200      252928
               26        -2      -11    0x33 . . FpBp. . B   0x000000BB3200      250368
               27         1      -12    0x22 . . Fp. . . P   0x000000BF5800      643584
               28         1      -13    0x33 . . FpBp. . B   0x000000C97E00      249856
               29        -2      -14    0x33 . . FpBp. . B   0x000000CDA200      247808
               30         1        0    0x40 . S . . . . I   0x000000D1BE00      951808
               31         1      -16    0x33 . . FpBp. . B   0x000000E09800      246272
               32        -2      -17    0x33 . . FpBp. . B   0x000000E4AE00      235520
               33         1       -3    0x22 . . Fp. . . P   0x000000E89A00      663552
               34         1       -4    0x33 . . FpBp. . B   0x000000F30E00      239104
              
  
  ```
  
  **Tags:** video, encoding, sony, gop
  
  > **Comments:**
  > **username_1**: Welcome! Are you having problems playing or working with the files or are you going through validation testing? Have you asked Sony about this? They tend to have their own interpretation of some of the standards.  
  > **username_0**: I'm trying to implement partial file restore from tape (the essence rewrapping part). My files are importable in FCP, Premiere Pro, but not Resolve. When I ran the file through some validation tools, I came across this issue. I don't know who to contact in Sony about this.  
  > **username_1**: If you are an end user, I'd start with sales or support. If you are vendor, you probably need to work through who ever handles channel partners. If you don't know who that is, and you are working with a specific client, I'd ask them to make the introduction.  
  
  ---
  
  ## 0 answers
  
  