why ffmpeg changes video stream from interlaced to progressive when it is set to copy the the stream I have a large video file that I try to chop into smaller pieces. The command I use is
ffmpeg.exe -i VideoTape-2007_09_09_19-20_05.avi -vcodec copy -acodec copy -ss 00:00:00.000 -t 00:10:33.761 VideoTape-2007_09_09_19-20_05-01.avi

According to MediaInfo, the original file is interlaced:

Video
ID                                       : 0
Format                                   : DV
Commercial name                          : DVCPRO
Duration                                 : 56 min 22 s
Bit rate mode                            : Constant
Bit rate                                 : 24.4 Mb/s
Encoded bit rate                         : 28.8 Mb/s
Width                                    : 720 pixels
Height                                   : 576 pixels
Display aspect ratio                     : 4:3
Frame rate mode                          : Constant
Frame rate                               : 25.000 FPS
Standard                                 : PAL
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Interlaced
Scan order                               : Bottom Field First
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 2.357
Time code of first frame                 : 00:02:26:16
Time code source                         : Subcode time code
Stream size                              : 11.3 GiB (100%)
Encoding settings                        : ae mode=full automatic / wb mode=automatic / white balance= / fcm=manual focus


after cutting, the output file has the following info:

Video
ID                                       : 0
Format                                   : DV
Commercial name                          : DVCPRO
Codec ID                                 : dvsd
Codec ID/Hint                            : Sony
Duration                                 : 10 min 33 s
Bit rate mode                            : Constant
Bit rate                                 : 24.4 Mb/s
Encoded bit rate                         : 28.8 Mb/s
Width                                    : 720 pixels
Height                                   : 576 pixels
Display aspect ratio                     : 4:3
Frame rate mode                          : Constant
Frame rate                               : 25.000 FPS
Standard                                 : PAL
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Original scan type                       : Interlaced
Original scan order                      : Bottom Field First
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 2.357
Time code of first frame                 : 00:00:00:02
Time code source                         : Subcode time code
Stream size                              : 2.12 GiB (97%)
Encoding settings                        : ae mode=full automatic / wb mode=automatic / white balance= / fcm=manual focus


Why is the Scan Type changed from Interlaced to Progressive? I just want to split the video.

I have also noticed that the resulting file in disproportionally large.
Looks like it is a FFmpeg bug.

I tested to remux an AVI with DV to AVI with latest FFmpeg, and the resulting "video properties" chunk indicates progressive, even if the source AVI has the right "video properties" chunk:

010F4   Video properties (76 bytes)
010F4    Header (8 bytes)
010F4     Name:                               vprp
010F8     Size:                               68 (0x00000044)
010FC    VideoFormatToken:                    0 (0x00000000)
01100    VideoStandard:                       0 (0x00000000)
01104    VerticalRefreshRate:                 50 (0x00000032)
01108    HTotalInT:                           720 (0x000002D0)
0110C    VTotalInLines:                       576 (0x00000240)
01110    FrameAspectRatio Height:             3 (0x0003)
01112    FrameAspectRatio Width:              4 (0x0004)
01114    FrameWidthInPixels:                  720 (0x000002D0)
01118    FrameHeightInLines:                  576 (0x00000240)
0111C    FieldPerFrame:                       1 (0x00000001)
01120    Field (32 bytes)
01120     CompressedBMHeight:                 576 (0x00000240)
01124     CompressedBMWidth:                  720 (0x000002D0)
01128     ValidBMHeight:                      576 (0x00000240)
0112C     ValidBMWidth:                       720 (0x000002D0)
01130     ValidBMXOffset:                     0 (0x00000000)
01134     ValidBMYOffset:                     0 (0x00000000)
01138     VideoXOffsetInT:                    0 (0x00000000)
0113C     VideoYValidStartLine:               0 (0x00000000)


It should be 

010F4   Video properties (108 bytes)
010F4    Header (8 bytes)
010F4     Name:                               vprp
010F8     Size:                               100 (0x00000064)
010FC    VideoFormatToken:                    0 (0x00000000)
01100    VideoStandard:                       0 (0x00000000)
01104    VerticalRefreshRate:                 50 (0x00000032)
01108    HTotalInT:                           720 (0x000002D0)
0110C    VTotalInLines:                       576 (0x00000240)
01110    FrameAspectRatio Height:             3 (0x0003)
01112    FrameAspectRatio Width:              4 (0x0004)
01114    FrameWidthInPixels:                  720 (0x000002D0)
01118    FrameHeightInLines:                  576 (0x00000240)
0111C    FieldPerFrame:                       2 (0x00000002)
01120    Field (32 bytes)
01120     CompressedBMHeight:                 288 (0x00000120)
01124     CompressedBMWidth:                  720 (0x000002D0)
01128     ValidBMHeight:                      288 (0x00000120)
0112C     ValidBMWidth:                       720 (0x000002D0)
01130     ValidBMXOffset:                     0 (0x00000000)
01134     ValidBMYOffset:                     0 (0x00000000)
01138     VideoXOffsetInT:                    0 (0x00000000)
0113C     VideoYValidStartLine:               1 (0x00000001)
01140    Field (32 bytes)
01140     CompressedBMHeight:                 288 (0x00000120)
01144     CompressedBMWidth:                  720 (0x000002D0)
01148     ValidBMHeight:                      288 (0x00000120)
0114C     ValidBMWidth:                       720 (0x000002D0)
01150     ValidBMXOffset:                     0 (0x00000000)
01154     ValidBMYOffset:                     0 (0x00000000)
01158     VideoXOffsetInT:                    0 (0x00000000)
0115C     VideoYValidStartLine:               0 (0x00000000)


I have open a bug ticket at FFmpeg tracker with an example about how to reproduce the issue.

Note that the DV stream is correctly remuxed only (it is still interlaced, no conversion), the issue is only a piece of metadata in the created AVI file, reason you see both "progressive" (from AVI) and "interlaced" (from DV) in the MediaInfo output.

Jérôme, main developer of MediaInfo.