simaaidecoder
=============

The ``simaaidecoder`` GStreamer plugin is a video decoder that supports H.264 and H.265 decoding. It integrates with SiMa.ai hardware for efficient video processing. The plugin outputs video frames in either NV12 or YUV420P format.

Properties
----------

The following properties can be configured for the ``simaaidecoder`` plugin:

========================= ======= ====================== ==============================================================================================================
Property Name             Type    Default Value          Description
========================= ======= ====================== ==============================================================================================================
dec-width                 int     0                      Video file resolution width.
dec-height                int     0                      Video file resolution height.
drop-threshold            int     1800                   Number of consecutive out-of-size frames before posting an MQTT message (requires external MQTT setup).
drop-on-resolution-change boolean FALSE                  When TRUE, any resolution change is dropped immediately.
dec-fps                   int     0                      Frames per second (FPS) control. Works only for ``dec-mode``: ``split-input`` mode.
dec-ip-cnt                int     2 (unalign), 5 (split) Decoder input buffer count. Default is 2 for ``unalign-input`` mode and 5 for ``split-input`` mode.
op-pool-cnt               int     30                     Plugin output buffer count from the pool, as specified in the ``next-element`` property.
ip-queue-max-buffers      int     60                     High watermark for the input queue; if exceeded, it blocks.
ip-queue-min-buffers      int     30                     Low watermark for the input queue.
dec-type                  string  h264                   Decoder type: either “h264” or “h265”.
dec-mode                  string  split-input            Decoder input mode: either “split-input” or “unalign-input”.
next-element              string  CVU                    Consumer of output: Choose one of “CVU”, “FPGA”, “ISP”, “APU” (currently only CVU and APU are supported).
apu-mem-pool              string  malloc                 A65 memory pool (works if ``next-element`` is APU): Choose “malloc” or “CMA(reserved)”.
dec-fmt                   string  NV12                   Output YUV format: either “NV12” or “YUV420P”.
dump-cnt                  int     0                      Number of decoded frames to be dumped to the specified path.
dump-path                 string  /tmp                   Path for decoded frames to be dumped.
memory-opt                boolean FALSE                  Optimize internal memory buffers. Note that this impacts performance; recommended only for multi-channels.
sima-allocator-type       int     1                      Type of SiMa allocator to use: 1 - no segment API, 2 - segment API support.
op-buff-name              string  simaaidecoder0         Output buffer name as a custom meta for output buffer (Default: plugin name, if no CM element-name is present)
op-buff-cached            boolean TRUE                   Specify if output buffers from the decoder are cached (applicable for CVU & CMA heap).
transmit                  boolean FALSE                  Transmit KPI messages.
========================= ======= ====================== ==============================================================================================================

Usage
-----

The ``simaaidecoder`` plugin is integrated into a GStreamer pipeline like this:

.. code:: bash

   gst-launch-1.0 filesrc location=input.mp4 ! h264parse ! simaaidecoder ! videoconvert ! autovideosink

Replace ``input.mp4`` with the actual path to your H.264 video file. For H.265, use ``h265parse`` instead of ``h264parse``. You can adjust properties using the ``simaaidecoder`` plugin’s properties as needed (e.g., ``simaaidecoder dec-width=1280 dec-height=720``).

Installation
------------

To install the ``simaaidecoder`` plugin, copy the plugin files from ``/usr/local/simaai/plugin_zoo/gst-simaai-plugins-base/gst/`` into your project’s ``plugins/`` directory.

Integration into a GStreamer Pipeline
-------------------------------------

The ``simaaidecoder`` plugin takes encoded video data (H.264 or H.265) as input on its sink pad and outputs decoded raw video data (NV12 or YUV420P) on its source pad. It’s essential to place appropriate upstream elements (e.g., ``filesrc``, ``h264parse``, ``h265parse``) to provide encoded data and downstream elements (e.g., ``videoconvert``, ``autovideosink``) to process the decoded output. The plugin leverages SiMa.ai libraries for hardware-accelerated decoding.