#702 MVC not merged with main AVC stream



I wanted to report a problem of recognition in the interlaced files In the example below the video site http://www.3dvisionfr.net/wp/2011/09/test-camescope-3d-sony-hdr-td10
The video is shot in two files in 3D SONY Camcorder are : 1920 * 1080 @ 50i and 1980 frames and media info return 988 an 989 frames @ 29.970 fps

Thank to all


  • Jerome Martinez

    Jerome Martinez - 2012-07-26


    Warning: non-paid bugs are set to low priority, I don't know when I have time to handle it.
    If you desire to accelerate the development, don't hesitate to contact me for a quotation.

  • Jerome Martinez

    Jerome Martinez - 2012-07-26
    • summary: problem of recognition --> MVC not merged with main AVC stream
    • status: open --> open-accepted
  • Jerome Martinez

    Jerome Martinez - 2012-07-26

    interlacement issue: it is mainly an issue with the MVC stream not merged with the AVC stream (so the scan type algorithm is wrong in that case). It is definitely interlaced content (both main stream and the MVC stream).

    I did not understand the remark about frame count / fps, files have 713 and 167 frames and are detected as 25 fps. (tested with v0.7.58)

  • shrecky

    shrecky - 2012-07-26


    What I mean is that other programs (VLC, eac3to, etc. ...) do return 50 fps 25 fps and not as MediaInfo.
    It is clear that the source is 50i and not 25i.
    Translated with google


  • Jerome Martinez

    Jerome Martinez - 2012-07-26

    VLC (and others?) are wrong, report a bug to them.
    To be precise:
    - it is 50i, yes. 25i has never(?) existed (but you can meet such character string because some people think it is better to write the count of frames per second for the number)
    - it is 50 **fields** per second. A field is half a frame. In that case it 50 times 540 lines.
    - it is 25 **frames** per second. A frame is 1080 lines

    A software saying that frame rate ("débit d'images" in French) is 50 for this file is wrong. the field rate ("débit de demi-images" in French?) is 50.

    For technical details if you are motivated to report a bug to other software:
    frame_mbs_only_flag is 0
    pic_order_cnt_type is 2
    num_units_in_ticks is 4800
    time_scale is 240000
    field_pic_flag is set in each slice...
    --> It is 50 fields per seconds (=25 frames per second), not 100 fields per seconds (=50 frames per second)

    FYI, this camera can do:
    - 2D at 50/60 fps (50p/60p)
    - 3D at 25/30 fps (50i/60i)

  • shrecky

    shrecky - 2012-07-27


    I remuxed directly with MKV Merge Gui (no reencoding) MTS and I get the right information
    Images par seconde : 50.000
    Images par seconde : 50,000 Im/s
    Images/s d'origine : 25.000
    Images/s d'origine : 25,000 Im/s
    Nombre d'images : 339

    Directly by MTS bad return
    Images par seconde : 25.000
    Images par seconde : 25,000 Im/s
    Nombre d'images : 167

  • Jerome Martinez

    Jerome Martinez - 2012-07-31


    Your link is good:
    "without increasing the number of complete frames per second"
    "For example, PAL video format is often specified as 576i50, where 576 indicates the total number of horizontal scan lines, i indicates interlacing, and 50 indicates 50 fields (half-frames) per second.*

    The important word is "half-frame". An "half-frame" is is not a frame. in PAL, there are 288 lines in field 1 (odd numbers of a frame), 288 lines in field 2 (even number of a frame), 50 times per second --> 25 frames per second.

    Do you really work in France Television and believe that standard in France is 50 frames per second? It is 25 frames per second, 50 fields (half-frame) per second, whatever you can believe. I don't understand how you can imagine 50 frames per second for your file or for PAL standard. It is not a 50 fps (with fps = "frames per second") stream, period. What is the problem? Again, I provide the video FRAME rate, not the video FIELD or half-frame rate in case of interlaced content. Read again the content of your link in order to do the difference between a video frame and a video field / half-frame. It is pretty dangerous for you in your job if you can not do the difference between a video frame and a video half-frame / field : there is a big loss of quality between 50p (= 50 frames per second) stream and 50i (= 50 fields per second) stream.

    If you want the field rate, you can simply:
    - multiply by 2 the frame rate in case of interlaced content without 3:2 pulldown (e.g. 25 fps and 50 fields per second)
    - multiply by 2.5 the frame rate in case of interlaced content with 3:2 pulldown (e.g. 24 fps and 60 fields per second)
    in order to have the field rate you are intersted in. MediaInfo does NOT provide any "field per second" info and I am not interested to provide such data by default. In MediaInfo, "fps" means "video FRAMES per second" in all cases (in case of interlaced content too). it never means "fields per second".

    BTW, the issue with Matroska is due to a misunderstanding of the Matroska specifications
    ("frame" in Matroska is technical and neutral, and can be a video frame, a video field, or an audio frame. It is not a "video frame")
    and it will be corrected soon

  • Jerome Martinez

    Jerome Martinez - 2012-07-31

    The MTS file is in 50i (again, it is 50 fields per seconds = 25 fps):
    The MTS file is not 3D side by side, it is MVC (the first eye with legacy "High@L4.1" profile, the second eye with "Stereo High@L4.1" profile). There are 50 fields per second per eye.
    each 1/50 second, there are 540 lines * 1920 pixels for each eye.

    The Matroska file is at 50 fps, without any weird stuff "Original frame rate" (it is set as 50 fps in both AVC stream and Matroska)
    each 1/50, there are 1080 lines * 960 pixels for each eye.

    - There is a big quality loss with width (960 pixels only vs 1920 lines in the original file). The image is downscaled somewhere with width.
    - There is an upscaled (540 --> 1080 lines) somewhere with height.
    - The stream is completely re-encoded. Big quality loss :(.

    I don't speak about frame doubler, it is interlaced --> progressive process, it is MVC --> AVC process, it is 1920*1080 per eye to 1920*1080 for both eye. So many things are changed between the two files.
    Whatever is the process (I don't know how you trransform a MVC stream to AVC stream), I only display the result of your transformation and the analysis of the source file.

    Note: Read again the specifications of the camcorder, it is written " 3D HD: 2x 1920x1080/60i;"
    Read again the Wikipedia page: 60i is 60 half-frames per second. It is NOT 60 frames per second.
    Technicaly, it is impossible to have 60 frames per second in 3D with this camcorder. The maximum is 60 half-frames per second in 3D. 60 fps is possible only in 2D. It is explicitely written, I don't know how to make it more explicit.

    I stop to argue about it, if you want to convince yourself, do it, I am not paid to teach about video. Specifications of the camcorder and the AVC/MVC stream I see are always against your imagination.

  • shrecky

    shrecky - 2012-08-02

    Excuse me I have made ​​a mistake

  • Jerome Martinez

    Jerome Martinez - 2012-08-02

    eh eh... Excuse accepted.
    Now I can work on real bugs :)


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