avdevice/decklink: add support for selecting devices based on their unique ID

Also bump the API version requirement to 10.9.5, because on olders versions
there were some reports of crashes using the undocumented, yet available
BMDDeckLinkDeviceHandle.

Signed-off-by: Marton Balint <cus@passwd.hu>

1 files changed, 40 insertions, 19 deletions

diff --git a/libavdevice/decklink_common.cpp b/libavdevice/decklink_common.cpp
index 503417bb35..b88d6c6219 100644
--- a/libavdevice/decklink_common.cpp
+++ b/libavdevice/decklink_common.cpp
@@ -77,15 +77,25 @@ static IDeckLinkIterator *decklink_create_iterator(AVFormatContext *avctx)
     return iter;
 }
 
-HRESULT ff_decklink_get_display_name(IDeckLink *This, const char **displayName)
+int decklink_get_attr_string(IDeckLink *dl, BMDDeckLinkAttributeID cfg_id, const char **s)
 {
-    DECKLINK_STR tmpDisplayName;
-    HRESULT hr = This->GetDisplayName(&tmpDisplayName);
-    if (hr != S_OK)
-        return hr;
-    *displayName = DECKLINK_STRDUP(tmpDisplayName);
-    DECKLINK_FREE(tmpDisplayName);
-    return hr;
+    DECKLINK_STR tmp;
+    HRESULT hr;
+    IDeckLinkAttributes *attr;
+    *s = NULL;
+    if (dl->QueryInterface(IID_IDeckLinkAttributes, (void **)&attr) != S_OK)
+        return AVERROR_EXTERNAL;
+    hr = attr->GetString(cfg_id, &tmp);
+    attr->Release();
+    if (hr == S_OK) {
+        *s = DECKLINK_STRDUP(tmp);
+        DECKLINK_FREE(tmp);
+        if (!*s)
+            return AVERROR(ENOMEM);
+    } else if (hr == E_FAIL) {
+        return AVERROR_EXTERNAL;
+    }
+    return 0;
 }
 
 static int decklink_select_input(AVFormatContext *avctx, BMDDeckLinkConfigurationID cfg_id)
@@ -276,11 +286,17 @@ int ff_decklink_list_devices(AVFormatContext *avctx,
     while (ret == 0 && iter->Next(&dl) == S_OK) {
         IDeckLinkOutput *output_config;
         IDeckLinkInput *input_config;
-        const char *displayName;
+        const char *display_name = NULL;
+        const char *unique_name = NULL;
         AVDeviceInfo *new_device = NULL;
         int add = 0;
 
-        ff_decklink_get_display_name(dl, &displayName);
+        ret = decklink_get_attr_string(dl, BMDDeckLinkDisplayName, &display_name);
+        if (ret < 0)
+            goto next;
+        ret = decklink_get_attr_string(dl, BMDDeckLinkDeviceHandle, &unique_name);
+        if (ret < 0)
+            goto next;
 
         if (show_outputs) {
             if (dl->QueryInterface(IID_IDeckLinkOutput, (void **)&output_config) == S_OK) {
@@ -303,8 +319,8 @@ int ff_decklink_list_devices(AVFormatContext *avctx,
                 goto next;
             }
 
-            new_device->device_name = av_strdup(displayName);
-            new_device->device_description = av_strdup(displayName);
+            new_device->device_name = av_strdup(unique_name ? unique_name : display_name);
+            new_device->device_description = av_strdup(display_name);
 
             if (!new_device->device_name ||
                 !new_device->device_description ||
@@ -318,7 +334,8 @@ int ff_decklink_list_devices(AVFormatContext *avctx,
         }
 
     next:
-        av_freep(&displayName);
+        av_freep(&display_name);
+        av_freep(&unique_name);
         dl->Release();
     }
     iter->Release();
@@ -343,7 +360,7 @@ void ff_decklink_list_devices_legacy(AVFormatContext *avctx,
         av_log(avctx, AV_LOG_INFO, "Blackmagic DeckLink %s devices:\n",
                show_inputs ? "input" : "output");
         for (int i = 0; i < device_list->nb_devices; i++) {
-            av_log(avctx, AV_LOG_INFO, "\t'%s'\n", device_list->devices[i]->device_name);
+            av_log(avctx, AV_LOG_INFO, "\t'%s'\n", device_list->devices[i]->device_description);
         }
     }
     avdevice_free_list_devices(&device_list);
@@ -427,14 +444,18 @@ int ff_decklink_init_device(AVFormatContext *avctx, const char* name)
         return AVERROR_EXTERNAL;
 
     while (iter->Next(&dl) == S_OK) {
-        const char *displayName;
-        ff_decklink_get_display_name(dl, &displayName);
-        if (!strcmp(name, displayName)) {
-            av_free((void *)displayName);
+        const char *display_name = NULL;
+        const char *unique_name = NULL;
+        decklink_get_attr_string(dl, BMDDeckLinkDisplayName, &display_name);
+        decklink_get_attr_string(dl, BMDDeckLinkDeviceHandle, &unique_name);
+        if (display_name && !strcmp(name, display_name) || unique_name && !strcmp(name, unique_name)) {
+            av_free((void *)unique_name);
+            av_free((void *)display_name);
             ctx->dl = dl;
             break;
         }
-        av_free((void *)displayName);
+        av_free((void *)display_name);
+        av_free((void *)unique_name);
         dl->Release();
     }
     iter->Release();