Incorrect scan type (AVI DV)
|Reported by:||laurfb||Owned by:||t.rapp|
|Blocking:||Reproduced by developer:||no|
|Analyzed by developer:||no|
Hi. I'm not sure if this is a normal behaviour or I'm doing something wrong.
I try to convert some videos to PAL DV AVI using ffmpeg-git (dvvideo encoder).
Always, checking resulted videos I found that mediainfo report AVI-DV as "Scan type: Progressive".
Even for simple avi dv to avi dv conversions.
ffmpeg -i pal_dv_orig.avi -c:v dvvideo pal_dv_ffmpeg.avi
With mediainfo pal_dv_orig.avi is described as
"Scan type : Interlaced
Scan order : Bottom Field First"
while for the resulted video file (pal_dv_ffmpeg.avi) mediainfo report:
"Scan type : Progressive
Original scan type : Interlaced
Original scan order : Bottom Field First"
According to Jerome Martinez (Mediainfo developer) to whom I asked for help:
"You see the two lines with "Original", which means there is a conflict between container (AVI) metadata and stream (DV) metadata.
DV in "ffmpeg" has same scan type as DV in "orig" (Interlaced, BFF).
but "ffmpeg" AVI contains a "vprp" chunk (Video properties) with FieldPerFrame of 1.
In your result file:
00010F4 Video properties (76 bytes)
00010F4 Header (8 bytes)
00010F4 Name: vprp
00010F8 Size: 68 (0x00000044)
00010FC VideoFormatToken: 0 (0x00000000)
0001100 VideoStandard: 0 (0x00000000)
0001104 VerticalRefreshRate: 25 (0x00000019)
0001108 HTotalInT: 720 (0x000002D0)
000110C VTotalInLines: 576 (0x00000240)
0001110 FrameAspectRatio Height: 9 (0x0009)
0001112 FrameAspectRatio Width: 16 (0x0010)
0001114 FrameWidthInPixels: 720 (0x000002D0)
0001118 FrameHeightInLines: 576 (0x00000240)
000111C FieldPerFrame: 1 (0x00000001)
0001120 Field (32 bytes)
0001120 CompressedBMHeight: 576 (0x00000240)
0001124 CompressedBMWidth: 720 (0x000002D0)
0001128 ValidBMHeight: 576 (0x00000240)
000112C ValidBMWidth: 720 (0x000002D0)
0001130 ValidBMXOffset: 0 (0x00000000)
0001134 ValidBMYOffset: 0 (0x00000000)
0001138 VideoXOffsetInT: 0 (0x00000000)
000113C VideoYValidStartLine: 0 (0x00000000)
(there is no "vprp" chunk in your "orig" file)
"Number of Fields Per Frame
One or two, depending on whether the video is interlaced or progressive"
Maybe I am wrong, but from my point of view "vprp" filling by FFmpeg is wrong for such interlaced content ("Number of Fields Per Frame" value should be 2 instead of 1), please ask FFmpeg developers for an argument about why "Number of Fields Per Frame" is 1 even for such interlaced content (maybe it means that both fields are in the same chunk? specs are not very explicit, I display what I understood from specs i.e. interlaced DV should use "2" for "Number of Fields Per Frame").
Note: in the same kind of issue, I see "25" for "refresh rate" and specs say "50 for PAL", but for frame rate I don't test this value for the moment.
So, is something about ffmpeg/dvvideo encoder, command used or mediainfo report is wrong?
Seems to be related on how ffmpeg pack DV stream in AVI container.
Change History (15)
comment:2 by , 4 years ago
|Component:||avcodec → avformat|
|Keywords:||avi added; vprp chunk FieldPerFrame removed|