logging and exporting electronic level data

[elenhil]

I wonder if it is possible to log and export real-time electronic level data to a sidecar file, to possibly use it in postprocessing for stabilization purposes?

[Walter Schulz]

https://www.magiclantern.fm/forum/index.php?topic=13229.msg127778#msg127778

[elenhil]

Thanks a ton, Walter!

[elenhil]

Is there some additional setting I need to turn on (besides electronic level) to log this data? So far the log file inside my MLVs is empty.

[Walter Schulz]

My settings:
Level enabled in ML overlay menu
MLV_REC allowed to use overlays
Preview option "Canon"

Extracted metadata with MLV_DUMP:

Code: [Select]

MLV_DUMP <myfile>.mlv -m -v

[...]
Block: ELVL
  Offset: 0x02733400
    Size: 32
    Time: 2257.355000 ms
     Roll:    3.00
     Pitch:   352.50
[...]
I hope roll and pitch are the one. Haven't used this before ...
EDIT: Excerpt from mlv_structure.h

Code: [Select]

typedef struct {
    uint8_t     blockType[4];    /* Electronic level (orientation) data */
    uint32_t    blockSize;
    uint64_t    timestamp;
    uint32_t    roll;    /* degrees x100 (here, 45.00 degrees) */
    uint32_t    pitch;    /* 10.00 degrees */
}  mlv_elvl_hdr_t;


[ML700D]

btw how to use in postprocessing?

[elenhil]

My settings:
Level enabled in ML overlay menu
MLV_REC allowed to use overlays
Preview option "Canon"

I'm afraid I don't recognize the last two options. Could you please elaborate?

[Walter Schulz]

Movie tab -> RAW video (MLV) -> [Q] ->
Global Draw: Allow
Preview Options: Canon

Don't know if these settings are necessary. I just wanted electronic level being visible during recording.

[elenhil]

Huh. Neither 60D nor 70D have the menu items under RAW video that you described. Oh, well. I do get the level displayed during recording anyway.

It's just that I can't find the level data. I had tried opening these MLVs with mlvfs, thinking these would be in log file inside. mlv_dump is new to me. I can't wrap my head around its structure. MLV_DUMP <myfile>.mlv -m -v seems to consist mostly of VIDF blocks. Is there a way to output just the ELVL blocks?

[Walter Schulz]

You are using MLV_LITE instead of MLV_REC ...
And please make yourself familiar with mlv_lite specs: https://www.magiclantern.fm/forum/index.php?topic=16650.0
"1. Metadata is only for what the settings were when recording was started (e.g. you get expo metadata, but if you change exposure, you don't get that new information)."

[elenhil]

Genius! Thank you very much, Walter!