lib(gstreamer): add shared encoded artifact directory helper

Add a reusable helper to resolve a shared encoded artifact directory for GStreamer video encode/decode workflows.

The helper allows suites to store encoded outputs in a job-shared location when running under LAVA testcase-specific
workspaces, while still falling back to the local suite output
directory for manual runs.

This is needed so encode and decode stages can exchange
generated files reliably across separate testcase directories.

Signed-off-by: Srikanth Muppandam <smuppand@qti.qualcomm.com>

Author: smuppand

Runner/utils/lib_gstreamer.sh

@@ -20,6 +20,31 @@ GSTLAUNCHFLAGS="${GSTLAUNCHFLAGS:--e -v -m}"
 # GST_ALSA_PLAYBACK_DEVICE=hw:0,0
 # GST_ALSA_CAPTURE_DEVICE=hw:0,1
 
+# -------------------- Shared encoded-artifact directory --------------------
+# gstreamer_shared_encoded_dir <script_dir> <outdir>
+# Prints a directory path to use for encoded video artifacts.
+# Priority:
+# 1. VIDEO_SHARED_ENCODE_DIR if explicitly provided
+# 2. A job-shared path derived from the common LAVA prefix before /tests/
+# 3. Fallback to <outdir>/encoded for local/manual runs
+gstreamer_shared_encoded_dir() {
+    script_dir="$1"
+    outdir="$2"
+
+    if [ -n "${VIDEO_SHARED_ENCODE_DIR:-}" ]; then
+        printf '%s\n' "$VIDEO_SHARED_ENCODE_DIR"
+        return 0
+    fi
+
+    case "$script_dir" in
+        */tests/*)
+            printf '%s/shared/video-encode-decode\n' "${script_dir%%/tests/*}"
+            ;;
+        *)
+            printf '%s/encoded\n' "$outdir"
+            ;;
+    esac
+}
 # -------------------- Element check --------------------
 has_element() {
   elem="$1"