Samples - adding a sample to illustrate StreamProvider for demuxer (#99)

* mem sample

* changes to match c++ style

* ffmpeg log

* readme update

* readme clean up

samples/videoDecodeMem/README.md

@@ -0,0 +1,37 @@
+# Video Decode Sample
+This sample illustrates a way to pass the data chunk-by-chunk sequentially to the FFMPEG demuxer which are then decoded on AMD hardware using rocDecode library.
+
+## Prerequisites:
+
+* Linux distribution
+  + Ubuntu - `20.04` / `22.04`
+
+* [ROCm supported hardware](https://rocm.docs.amd.com/en/latest/release/gpu_os_support.html)
+
+* Install [ROCm 5.5 or later](https://rocmdocs.amd.com/en/latest/deploy/linux/installer/install.html) with `--usecase=graphics,rocm --no-32`
+
+* rocDecode
+
+* CMake `3.5` or later
+
+* [FFMPEG](https://ffmpeg.org/about.html)
+  ```
+  sudo apt install ffmpeg
+  ```
+
+## Build
+```
+mkdir build
+cd build
+cmake ../
+make -j
+```
+# Run 
+```
+./videodecodemem -i <input video file [required]> 
+              -o <output path to save decoded YUV frames [optional]> 
+              -d <GPU device ID - 0:device 0 / 1:device 1/ ... [optional - default:0]>
+              -z <force_zero_latency - Decoded frames will be flushed out for display immediately [optional]>
+              -sei <extract SEI messages [optional]>
+              -crop <crop rectangle for output (not used when using interopped decoded frame) [optional - default: 0,0,0,0]>
+```