[Bug 763026] dc1394: port to 1.X

Thu Jun 9 22:03:40 UTC 2016

https://bugzilla.gnome.org/show_bug.cgi?id=763026

Tim-Philipp Müller <t.i.m at zen.co.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|git master                  |1.9.1

--- Comment #18 from Tim-Philipp Müller <t.i.m at zen.co.uk> ---
Superb, thanks! Let's get this in. Please file any follow-up patches in new
bugs, thanks!

commit faf6e5a1eb757815d3e6ff49765e79b9895d4e48
Author: Tim-Philipp Müller <tim at centricular.com>
Date:   Thu Jun 9 22:01:45 2016 +0100

    dc1394src: minor clean-up

    We always call _parse_caps() with non-NULL out vars.

commit 09737d1874467558f51313fdf1d089edeccccdf8
Author: Tim-Philipp Müller <tim at centricular.com>
Date:   Thu Jun 9 22:01:13 2016 +0100

    dc1394src: fix some more c99-isms

commit c8b7585dce782518d0b6f96a1cef4f7a85939820
Author: Tim-Philipp Müller <tim at centricular.com>
Date:   Thu Jun 9 21:47:05 2016 +0100

    docs: fix for renamed dc1394 source file

    https://bugzilla.gnome.org/show_bug.cgi?id=763026

commit 3355f5b3ab2357844e1bd6baded88c7a286184cd
Author: Joan Pau Beltran <joanpau.beltran at socib.cat>
Date:   Tue Jun 7 15:50:50 2016 +0200

    dc1394src: prefix and file names according to Gstreamer conventions

    Replace the type and function prefix to follow the conventions:

      - Use `GST_TYPE_DC1394_SRC` instead of `GST_TYPE_DC1394`.

      - Use `GstDC1394Src` and `GstDC1394SrcClass` instead of
        `GstDc1394` and `GstDc1394Class`.

      - Use `gst_dc1394_src` instead of `gst_dc1394`.

    https://bugzilla.gnome.org/show_bug.cgi?id=763026

commit e28b1236084a134007ae69f4dc94f2d98a2d16e1
Author: Joan Pau Beltran <joanpau.beltran at socib.cat>
Date:   Tue May 10 18:30:35 2016 +0200

    dc1394src: port to 1.X

    The dc1394src is a PushSrc element for IIDC cameras based on libdc1394.
    The implementation from the 0.x series is deffective:
    caps negotiation does not work, and some video formats
    provided by the camera are not supported.

    Refactor the code to port it to 1.X and enhance the support
    for the full set of video options of IIDC cameras:

      - The IIDC specification includes a set of camera video modes
        (video format, frame size, and frame rates).
        They do not map perfectly to Gstreamer formats, but those that
        do not match are very rare (if used at all by any camera).
        In addition, although the specification includes a raw format,
        some cameras use mono video formats to capture in Bayer format.
        Map corresponding video modes to Gstreamer formats in capabilities,
        allowing both gray raw and Bayer video formats for mono video modes.

      - The specification includes scalable video modes (Format7),
        where the frame size and rate can be set to arbitrary values
        (within the limits of the camera and the bus transport).
        Allow the use of such mode, using the frame size and rate
        from the negotiatied caps, and set the camera frame rate
        adjusting the packet size as in:

<http://damien.douxchamps.net/ieee1394/libdc1394/faq/#How_do_I_set_the_frame_rate>

        The scalable modes also allow for a custom ROI offset.
        Support for it can be easily added later using properties.

      - Camera operation using libdc1394 is as follows:

          1. Enumerate cameras on the system and open the camera
             identified the enumeration index or by a GUID (64bit hex code).

          2. Query the video formats supported by the camera.

          3. Configure the camera for the desired video format.

          4. Setup the capture resources for the configured video format
             and start the camera transmission.

          5. Capture frames from the camera and release them when not used.

          6. Stop the camera transmission and clear the capture resources.

          7. Close the camera freeing its resources.

        Do steps 2 and 3 when getting and setting the caps respectively.
        Ideally 4 and 6 would be done when going from PAUSED to PLAYING
        and viceversa, but since caps might not be set yet, the video mode
        is not properly configured leaving the camera in a broken state.
        Hence, setup capture and start transmission in the set caps method,
        and consequently clear the capture and stop the transmission
        when going from PAUSED to READY (instead of PLAYING to PAUSED).
        Symmetrycally, open the camera when going from READY to PAUSED,
        allowing to probe the camera caps in the negotiation stage.
        Implement that using the `start` and `stop` methods of `GstBaseSrc`,
        instead of the `change-state` method of `GstElement`.
        Stop the camera before setting new caps and restarting it again
        to handle caps reconfiguration while in PLAYING (it has no effect
        if the camera is not started).

      - Create buffers copying the bytes of the captured frames.
        Alternatively, the buffers could just wrap the bytes of the frames,
        releasing the frame in the buffer's destroy notify function,
        if all buffers were destroyed before going from PLAYING to PAUSED.

      - No timestamp nor offset is set when creating buffers.
        Timestamping is delegated to the parent class BaseSrc,
        setting `gst_base_src_set_live` TRUE, `gst_base_src_set_format`
        with GST_FORMAT_TIME and `gst_base_src_set_do_timestamp`.
        Captured frames have a timestamp field with the system time
        at the completion of the transmission of the frame,
        but it is not sure that this comes from a monotonic clock,
        and it seems to be left NULL in Windows.

      - Use GUID and unit properties to select the camera to operate on.
        The camera number used in version 0.X does not uniquely identify
        the device (it depends on the set of cameras currently detected).
        Since the GUID is 64bit identifier (same as MAC address),
        handle it with a string property with its hexadecimal representation.
        For practicality, operate on the first camera available if the GUID
        is null (default) and match any camera unit number if unit is -1.
        Alternatively, the GUID could be handed with an unsigned 64 bit
        integer type property, using `0xffffffffffffffff` as default value
        to select the first camera available (it is not a valid GUID value).

      - Keep name `GstDc1394` and prefix `gst_dc1394` as in version 0.X,
        although `GstDC1394Src` and `gst_dc1394_src` are more descriptive.

      - Adjust build files to reenable the compilation of the plugin.

        Remove dc1394 from the list of unported plugins in configure.ac.

        Add the missing flags and libraries to Makefile.
        Use `$()` for variable substitution, as many plugins do,
        although other plugins use `@@` instead.

    https://bugzilla.gnome.org/show_bug.cgi?id=763026

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are the assignee for the bug.