avdevice/decklink: move general code of decklink encoder to common file

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

7 files changed, 380 insertions, 193 deletions

diff --git a/libavdevice/Makefile b/libavdevice/Makefile
index db301e7112..f90c0f73c7 100644
--- a/libavdevice/Makefile
+++ b/libavdevice/Makefile
@@ -16,7 +16,7 @@ OBJS-$(CONFIG_ALSA_OUTDEV)               += alsa-audio-common.o \
 OBJS-$(CONFIG_AVFOUNDATION_INDEV)        += avfoundation.o
 OBJS-$(CONFIG_BKTR_INDEV)                += bktr.o
 OBJS-$(CONFIG_CACA_OUTDEV)               += caca.o
-OBJS-$(CONFIG_DECKLINK_OUTDEV)           += decklink_enc.o decklink_enc_c.o
+OBJS-$(CONFIG_DECKLINK_OUTDEV)           += decklink_enc.o decklink_enc_c.o decklink_common.o
 OBJS-$(CONFIG_DSHOW_INDEV)               += dshow.o dshow_enummediatypes.o \
                                             dshow_enumpins.o dshow_filter.o \
                                             dshow_pin.o dshow_common.o
@@ -57,7 +57,7 @@ OBJS-$(HAVE_LIBC_MSVCRT)                 += file_open.o
 # Windows resource file
 SLIBOBJS-$(HAVE_GNU_WINDRES)             += avdeviceres.o
 
-SKIPHEADERS-$(CONFIG_DECKLINK)           += decklink_enc.h
+SKIPHEADERS-$(CONFIG_DECKLINK)           += decklink_enc.h decklink_common.h
 SKIPHEADERS-$(CONFIG_DSHOW_INDEV)        += dshow_capture.h
 SKIPHEADERS-$(CONFIG_FBDEV_INDEV)        += fbdev_common.h
 SKIPHEADERS-$(CONFIG_FBDEV_OUTDEV)       += fbdev_common.h
diff --git a/libavdevice/decklink_common.cpp b/libavdevice/decklink_common.cpp
new file mode 100644
index 0000000000..9a9e44bf3c
--- /dev/null
+++ b/libavdevice/decklink_common.cpp
@@ -0,0 +1,229 @@
+/*
+ * Blackmagic DeckLink output
+ * Copyright (c) 2013-2014 Ramiro Polla, Luca Barbato, Deti Fliegl
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <DeckLinkAPI.h>
+#ifdef _WIN32
+#include <DeckLinkAPI_i.c>
+#else
+#include <DeckLinkAPIDispatch.cpp>
+#endif
+
+#include <pthread.h>
+#include <semaphore.h>
+
+extern "C" {
+#include "libavformat/avformat.h"
+#include "libavformat/internal.h"
+#include "libavutil/imgutils.h"
+}
+
+#include "decklink_common.h"
+
+#ifdef _WIN32
+IDeckLinkIterator *CreateDeckLinkIteratorInstance(void)
+{
+    IDeckLinkIterator *iter;
+
+    if (CoInitialize(NULL) != S_OK) {
+        av_log(NULL, AV_LOG_ERROR, "COM initialization failed.\n");
+        return NULL;
+    }
+
+    if (CoCreateInstance(CLSID_CDeckLinkIterator, NULL, CLSCTX_ALL,
+                         IID_IDeckLinkIterator, (void**) &iter) != S_OK) {
+        av_log(NULL, AV_LOG_ERROR, "DeckLink drivers not installed.\n");
+        return NULL;
+    }
+
+    return iter;
+}
+#endif
+
+#ifdef _WIN32
+static char *dup_wchar_to_utf8(wchar_t *w)
+{
+    char *s = NULL;
+    int l = WideCharToMultiByte(CP_UTF8, 0, w, -1, 0, 0, 0, 0);
+    s = (char *) av_malloc(l);
+    if (s)
+        WideCharToMultiByte(CP_UTF8, 0, w, -1, s, l, 0, 0);
+    return s;
+}
+#define DECKLINK_STR    OLECHAR *
+#define DECKLINK_STRDUP dup_wchar_to_utf8
+#else
+#define DECKLINK_STR    const char *
+#define DECKLINK_STRDUP av_strdup
+#endif
+
+HRESULT ff_decklink_get_display_name(IDeckLink *This, const char **displayName)
+{
+    DECKLINK_STR tmpDisplayName;
+    HRESULT hr = This->GetDisplayName(&tmpDisplayName);
+    if (hr != S_OK)
+        return hr;
+    *displayName = DECKLINK_STRDUP(tmpDisplayName);
+    /* free() is needed for a string returned by the DeckLink SDL. */
+    free((void *) tmpDisplayName);
+    return hr;
+}
+
+int ff_decklink_set_format(AVFormatContext *avctx,
+                               int width, int height,
+                               int tb_num, int tb_den,
+                               decklink_direction_t direction, int num)
+{
+    struct decklink_cctx *cctx = (struct decklink_cctx *) avctx->priv_data;
+    struct decklink_ctx *ctx = (struct decklink_ctx *)cctx->ctx;
+    BMDDisplayModeSupport support;
+    IDeckLinkDisplayModeIterator *itermode;
+    IDeckLinkDisplayMode *mode;
+    int i = 1;
+    HRESULT res;
+
+    if (direction == DIRECTION_IN) {
+        res = ctx->dli->GetDisplayModeIterator (&itermode);
+    } else {
+        res = ctx->dlo->GetDisplayModeIterator (&itermode);
+    }
+
+    if (res!= S_OK) {
+            av_log(avctx, AV_LOG_ERROR, "Could not get Display Mode Iterator\n");
+            return AVERROR(EIO);
+    }
+
+
+    if (tb_num == 1) {
+        tb_num *= 1000;
+        tb_den *= 1000;
+    }
+    ctx->bmd_mode = bmdModeUnknown;
+    while ((ctx->bmd_mode == bmdModeUnknown) && itermode->Next(&mode) == S_OK) {
+        BMDTimeValue bmd_tb_num, bmd_tb_den;
+        int bmd_width  = mode->GetWidth();
+        int bmd_height = mode->GetHeight();
+
+        mode->GetFrameRate(&bmd_tb_num, &bmd_tb_den);
+
+        if ((bmd_width == width && bmd_height == height &&
+            bmd_tb_num == tb_num && bmd_tb_den == tb_den) || i == num) {
+            ctx->bmd_mode   = mode->GetDisplayMode();
+            ctx->bmd_width  = bmd_width;
+            ctx->bmd_height = bmd_height;
+            ctx->bmd_tb_den = bmd_tb_den;
+            ctx->bmd_tb_num = bmd_tb_num;
+            ctx->bmd_field_dominance = mode->GetFieldDominance();
+            av_log(avctx, AV_LOG_INFO, "Found Decklink mode %d x %d with rate %.2f%s\n",
+                bmd_width, bmd_height, (float)bmd_tb_den/(float)bmd_tb_num,
+                (ctx->bmd_field_dominance==bmdLowerFieldFirst || ctx->bmd_field_dominance==bmdUpperFieldFirst)?"(i)":"");
+        }
+
+        mode->Release();
+        i++;
+    }
+
+    itermode->Release();
+
+    if (ctx->bmd_mode == bmdModeUnknown)
+        return -1;
+    if (direction == DIRECTION_IN) {
+        if (ctx->dli->DoesSupportVideoMode(ctx->bmd_mode, bmdFormat8BitYUV,
+                                           bmdVideoOutputFlagDefault,
+                                           &support, NULL) != S_OK)
+            return -1;
+    } else {
+        if (ctx->dlo->DoesSupportVideoMode(ctx->bmd_mode, bmdFormat8BitYUV,
+                                           bmdVideoOutputFlagDefault,
+                                           &support, NULL) != S_OK)
+        return -1;
+    }
+    if (support == bmdDisplayModeSupported)
+        return 0;
+
+    return -1;
+}
+
+int ff_decklink_set_format(AVFormatContext *avctx, decklink_direction_t direction, int num) {
+    return ff_decklink_set_format(avctx, 0, 0, 0, 0, direction, num);
+}
+
+int ff_decklink_list_devices(AVFormatContext *avctx)
+{
+    IDeckLink *dl = NULL;
+    IDeckLinkIterator *iter = CreateDeckLinkIteratorInstance();
+    if (!iter) {
+        av_log(avctx, AV_LOG_ERROR, "Could not create DeckLink iterator\n");
+        return AVERROR(EIO);
+    }
+    av_log(avctx, AV_LOG_INFO, "Blackmagic DeckLink devices:\n");
+    while (iter->Next(&dl) == S_OK) {
+        const char *displayName;
+        ff_decklink_get_display_name(dl, &displayName);
+        av_log(avctx, AV_LOG_INFO, "\t'%s'\n", displayName);
+        av_free((void *) displayName);
+        dl->Release();
+    }
+    iter->Release();
+    return 0;
+}
+
+int ff_decklink_list_formats(AVFormatContext *avctx, decklink_direction_t direction)
+{
+    struct decklink_cctx *cctx = (struct decklink_cctx *) avctx->priv_data;
+    struct decklink_ctx *ctx = (struct decklink_ctx *)cctx->ctx;
+    IDeckLinkDisplayModeIterator *itermode;
+    IDeckLinkDisplayMode *mode;
+    int i=0;
+    HRESULT res;
+
+    if (direction == DIRECTION_IN) {
+        res = ctx->dli->GetDisplayModeIterator (&itermode);
+    } else {
+        res = ctx->dlo->GetDisplayModeIterator (&itermode);
+    }
+
+    if (res!= S_OK) {
+            av_log(avctx, AV_LOG_ERROR, "Could not get Display Mode Iterator\n");
+            return AVERROR(EIO);
+    }
+
+    av_log(avctx, AV_LOG_INFO, "Supported formats for '%s':\n",
+               avctx->filename);
+    while (itermode->Next(&mode) == S_OK) {
+        BMDTimeValue tb_num, tb_den;
+        mode->GetFrameRate(&tb_num, &tb_den);
+        av_log(avctx, AV_LOG_INFO, "\t%d\t%ldx%ld at %d/%d fps",
+                ++i,mode->GetWidth(), mode->GetHeight(),
+                (int) tb_den, (int) tb_num);
+        switch (mode->GetFieldDominance()) {
+        case bmdLowerFieldFirst:
+        av_log(avctx, AV_LOG_INFO, " (interlaced, lower field first)"); break;
+        case bmdUpperFieldFirst:
+        av_log(avctx, AV_LOG_INFO, " (interlaced, upper field first)"); break;
+        }
+        av_log(avctx, AV_LOG_INFO, "\n");
+        mode->Release();
+    }
+
+    itermode->Release();
+
+    return 0;
+}
diff --git a/libavdevice/decklink_common.h b/libavdevice/decklink_common.h
new file mode 100644
index 0000000000..544da27836
--- /dev/null
+++ b/libavdevice/decklink_common.h
@@ -0,0 +1,98 @@
+/*
+ * Blackmagic DeckLink common code
+ * Copyright (c) 2013-2014 Ramiro Polla, Luca Barbato, Deti Fliegl
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "decklink_common_c.h"
+
+class decklink_output_callback;
+class decklink_input_callback;
+
+typedef struct AVPacketQueue {
+    AVPacketList *first_pkt, *last_pkt;
+    int nb_packets;
+    unsigned long long size;
+    int abort_request;
+    pthread_mutex_t mutex;
+    pthread_cond_t cond;
+    AVFormatContext *avctx;
+} AVPacketQueue;
+
+struct decklink_ctx {
+    /* DeckLink SDK interfaces */
+    IDeckLink *dl;
+    IDeckLinkOutput *dlo;
+    IDeckLinkInput *dli;
+    decklink_output_callback *output_callback;
+    decklink_input_callback *input_callback;
+
+    /* DeckLink mode information */
+    BMDTimeValue bmd_tb_den;
+    BMDTimeValue bmd_tb_num;
+    BMDDisplayMode bmd_mode;
+    int bmd_width;
+    int bmd_height;
+    int bmd_field_dominance;
+
+    /* Capture buffer queue */
+    AVPacketQueue queue;
+
+    /* Streams present */
+    int audio;
+    int video;
+
+    /* Status */
+    int playback_started;
+    int capture_started;
+    int64_t last_pts;
+    unsigned long frameCount;
+    unsigned int dropped;
+    AVStream *audio_st;
+    AVStream *video_st;
+
+    /* Options */
+    int list_devices;
+    int list_formats;
+    double preroll;
+
+    int frames_preroll;
+    int frames_buffer;
+
+    sem_t semaphore;
+
+    int channels;
+};
+
+typedef enum { DIRECTION_IN, DIRECTION_OUT} decklink_direction_t;
+
+#ifdef _WIN32
+typedef unsigned long buffercount_type;
+IDeckLinkIterator *CreateDeckLinkIteratorInstance(void);
+char *dup_wchar_to_utf8(wchar_t *w);
+#else
+typedef uint32_t buffercount_type;
+#endif
+
+
+HRESULT ff_decklink_get_display_name(IDeckLink *This, const char **displayName);
+int ff_decklink_set_format(AVFormatContext *avctx, int width, int height, int tb_num, int tb_den, decklink_direction_t direction = DIRECTION_OUT, int num = 0);
+int ff_decklink_set_format(AVFormatContext *avctx, decklink_direction_t direction, int num);
+int ff_decklink_list_devices(AVFormatContext *avctx);
+int ff_decklink_list_formats(AVFormatContext *avctx, decklink_direction_t direction = DIRECTION_OUT);
+
diff --git a/libavdevice/decklink_common_c.h b/libavdevice/decklink_common_c.h
new file mode 100644
index 0000000000..861a51aa12
--- /dev/null
+++ b/libavdevice/decklink_common_c.h
@@ -0,0 +1,32 @@
+/*
+ * Blackmagic DeckLink common code
+ * Copyright (c) 2013-2014 Ramiro Polla
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+struct decklink_cctx {
+    const AVClass *cclass;
+
+    void *ctx;
+
+    /* Options */
+    int list_devices;
+    int list_formats;
+    double preroll;
+};
+
diff --git a/libavdevice/decklink_enc.cpp b/libavdevice/decklink_enc.cpp
index 3d7cbe237c..6c5450f4ec 100644
--- a/libavdevice/decklink_enc.cpp
+++ b/libavdevice/decklink_enc.cpp
@@ -20,13 +20,6 @@
  */
 
 #include <DeckLinkAPI.h>
-#ifdef _WIN32
-#include <DeckLinkAPI_i.c>
-typedef unsigned long buffercount_type;
-#else
-#include <DeckLinkAPIDispatch.cpp>
-typedef uint32_t buffercount_type;
-#endif
 
 #include <pthread.h>
 #include <semaphore.h>
@@ -37,44 +30,9 @@ extern "C" {
 #include "libavutil/imgutils.h"
 }
 
+#include "decklink_common.h"
 #include "decklink_enc.h"
 
-class decklink_callback;
-
-struct decklink_ctx {
-    /* DeckLink SDK interfaces */
-    IDeckLink *dl;
-    IDeckLinkOutput *dlo;
-    decklink_callback *callback;
-
-    /* DeckLink mode information */
-    IDeckLinkDisplayModeIterator *itermode;
-    BMDTimeValue bmd_tb_den;
-    BMDTimeValue bmd_tb_num;
-    BMDDisplayMode bmd_mode;
-    int bmd_width;
-    int bmd_height;
-
-    /* Streams present */
-    int audio;
-    int video;
-
-    /* Status */
-    int playback_started;
-    int64_t last_pts;
-
-    /* Options */
-    int list_devices;
-    int list_formats;
-    double preroll;
-
-    int frames_preroll;
-    int frames_buffer;
-
-    sem_t semaphore;
-
-    int channels;
-};
 
 /* DeckLink callback class declaration */
 class decklink_frame : public IDeckLinkVideoFrame
@@ -109,7 +67,7 @@ private:
     int   _refs;
 };
 
-class decklink_callback : public IDeckLinkVideoOutputCallback
+class decklink_output_callback : public IDeckLinkVideoOutputCallback
 {
 public:
     virtual HRESULT STDMETHODCALLTYPE ScheduledFrameCompleted(IDeckLinkVideoFrame *_frame, BMDOutputFrameCompletionResult result)
@@ -130,99 +88,6 @@ public:
     virtual ULONG   STDMETHODCALLTYPE Release(void)                           { return 1; }
 };
 
-#ifdef _WIN32
-static IDeckLinkIterator *CreateDeckLinkIteratorInstance(void)
-{
-    IDeckLinkIterator *iter;
-
-    if (CoInitialize(NULL) != S_OK) {
-        av_log(NULL, AV_LOG_ERROR, "COM initialization failed.\n");
-        return NULL;
-    }
-
-    if (CoCreateInstance(CLSID_CDeckLinkIterator, NULL, CLSCTX_ALL,
-                         IID_IDeckLinkIterator, (void**) &iter) != S_OK) {
-        av_log(NULL, AV_LOG_ERROR, "DeckLink drivers not installed.\n");
-        return NULL;
-    }
-
-    return iter;
-}
-#endif
-
-/* free() is needed for a string returned by the DeckLink SDL. */
-#undef free
-
-#ifdef _WIN32
-static char *dup_wchar_to_utf8(wchar_t *w)
-{
-    char *s = NULL;
-    int l = WideCharToMultiByte(CP_UTF8, 0, w, -1, 0, 0, 0, 0);
-    s = (char *) av_malloc(l);
-    if (s)
-        WideCharToMultiByte(CP_UTF8, 0, w, -1, s, l, 0, 0);
-    return s;
-}
-#define DECKLINK_STR    OLECHAR *
-#define DECKLINK_STRDUP dup_wchar_to_utf8
-#else
-#define DECKLINK_STR    const char *
-#define DECKLINK_STRDUP av_strdup
-#endif
-
-static HRESULT IDeckLink_GetDisplayName(IDeckLink *This, const char **displayName)
-{
-    DECKLINK_STR tmpDisplayName;
-    HRESULT hr = This->GetDisplayName(&tmpDisplayName);
-    if (hr != S_OK)
-        return hr;
-    *displayName = DECKLINK_STRDUP(tmpDisplayName);
-    free((void *) tmpDisplayName);
-    return hr;
-}
-
-static int decklink_set_format(struct decklink_ctx *ctx,
-                               int width, int height,
-                               int tb_num, int tb_den)
-{
-    BMDDisplayModeSupport support;
-    IDeckLinkDisplayMode *mode;
-
-    if (tb_num == 1) {
-        tb_num *= 1000;
-        tb_den *= 1000;
-    }
-    ctx->bmd_mode = bmdModeUnknown;
-    while ((ctx->bmd_mode == bmdModeUnknown) && ctx->itermode->Next(&mode) == S_OK) {
-        BMDTimeValue bmd_tb_num, bmd_tb_den;
-        int bmd_width  = mode->GetWidth();
-        int bmd_height = mode->GetHeight();
-
-        mode->GetFrameRate(&bmd_tb_num, &bmd_tb_den);
-
-        if (bmd_width == width && bmd_height == height &&
-            bmd_tb_num == tb_num && bmd_tb_den == tb_den) {
-            ctx->bmd_mode   = mode->GetDisplayMode();
-            ctx->bmd_width  = bmd_width;
-            ctx->bmd_height = bmd_height;
-            ctx->bmd_tb_den = bmd_tb_den;
-            ctx->bmd_tb_num = bmd_tb_num;
-        }
-
-        mode->Release();
-    }
-    if (ctx->bmd_mode == bmdModeUnknown)
-        return -1;
-    if (ctx->dlo->DoesSupportVideoMode(ctx->bmd_mode, bmdFormat8BitYUV,
-                                       bmdVideoOutputFlagDefault,
-                                       &support, NULL) != S_OK)
-        return -1;
-    if (support == bmdDisplayModeSupported)
-        return 0;
-
-    return -1;
-}
-
 static int decklink_setup_video(AVFormatContext *avctx, AVStream *st)
 {
     struct decklink_cctx *cctx = (struct decklink_cctx *) avctx->priv_data;
@@ -239,7 +104,7 @@ static int decklink_setup_video(AVFormatContext *avctx, AVStream *st)
                " Only AV_PIX_FMT_UYVY422 is supported.\n");
         return -1;
     }
-    if (decklink_set_format(ctx, c->width, c->height,
+    if (ff_decklink_set_format(avctx, c->width, c->height,
                             c->time_base.num, c->time_base.den)) {
         av_log(avctx, AV_LOG_ERROR, "Unsupported video size or framerate!"
                " Check available formats with -list_formats 1.\n");
@@ -252,8 +117,8 @@ static int decklink_setup_video(AVFormatContext *avctx, AVStream *st)
     }
 
     /* Set callback. */
-    ctx->callback = new decklink_callback();
-    ctx->dlo->SetScheduledFrameCompletionCallback(ctx->callback);
+    ctx->output_callback = new decklink_output_callback();
+    ctx->dlo->SetScheduledFrameCompletionCallback(ctx->output_callback);
 
     /* Start video semaphore. */
     ctx->frames_preroll = c->time_base.den * ctx->preroll;
@@ -333,8 +198,8 @@ av_cold int ff_decklink_write_trailer(AVFormatContext *avctx)
     if (ctx->dl)
         ctx->dl->Release();
 
-    if (ctx->callback)
-        delete ctx->callback;
+    if (ctx->output_callback)
+        delete ctx->output_callback;
 
     sem_destroy(&ctx->semaphore);
 
@@ -450,6 +315,7 @@ av_cold int ff_decklink_write_header(AVFormatContext *avctx)
 {
     struct decklink_cctx *cctx = (struct decklink_cctx *) avctx->priv_data;
     struct decklink_ctx *ctx;
+    IDeckLinkDisplayModeIterator *itermode;
     IDeckLinkIterator *iter;
     IDeckLink *dl = NULL;
     unsigned int n;
@@ -470,22 +336,14 @@ av_cold int ff_decklink_write_header(AVFormatContext *avctx)
 
     /* List available devices. */
     if (ctx->list_devices) {
-        av_log(avctx, AV_LOG_INFO, "Blackmagic DeckLink devices:\n");
-        while (iter->Next(&dl) == S_OK) {
-            const char *displayName;
-            IDeckLink_GetDisplayName(dl, &displayName);
-            av_log(avctx, AV_LOG_INFO, "\t'%s'\n", displayName);
-            av_free((void *) displayName);
-            dl->Release();
-        }
-        iter->Release();
+        ff_decklink_list_devices(avctx);
         return AVERROR_EXIT;
     }
 
     /* Open device. */
     while (iter->Next(&dl) == S_OK) {
         const char *displayName;
-        IDeckLink_GetDisplayName(dl, &displayName);
+        ff_decklink_get_display_name(dl, &displayName);
         if (!strcmp(avctx->filename, displayName)) {
             av_free((void *) displayName);
             ctx->dl = dl;
@@ -508,40 +366,20 @@ av_cold int ff_decklink_write_header(AVFormatContext *avctx)
         return AVERROR(EIO);
     }
 
-    if (ctx->dlo->GetDisplayModeIterator(&ctx->itermode) != S_OK) {
-        av_log(avctx, AV_LOG_ERROR, "Could not get Display Mode Iterator\n");
-        ctx->dl->Release();
-        return AVERROR(EIO);
-    }
-
     /* List supported formats. */
     if (ctx->list_formats) {
-        IDeckLinkDisplayMode *mode;
-
-        av_log(avctx, AV_LOG_INFO, "Supported formats for '%s':\n",
-               avctx->filename);
-        while (ctx->itermode->Next(&mode) == S_OK) {
-            BMDTimeValue tb_num, tb_den;
-            mode->GetFrameRate(&tb_num, &tb_den);
-            av_log(avctx, AV_LOG_INFO, "\t%ldx%ld at %d/%d fps",
-                   mode->GetWidth(), mode->GetHeight(),
-                   (int) tb_den, (int) tb_num);
-            switch (mode->GetFieldDominance()) {
-            case bmdLowerFieldFirst:
-            av_log(avctx, AV_LOG_INFO, " (interlaced, lower field first)"); break;
-            case bmdUpperFieldFirst:
-            av_log(avctx, AV_LOG_INFO, " (interlaced, upper field first)"); break;
-            }
-            av_log(avctx, AV_LOG_INFO, "\n");
-            mode->Release();
-        }
-
-        ctx->itermode->Release();
+        ff_decklink_list_formats(avctx);
         ctx->dlo->Release();
         ctx->dl->Release();
         return AVERROR_EXIT;
     }
 
+    if (ctx->dlo->GetDisplayModeIterator(&itermode) != S_OK) {
+        av_log(avctx, AV_LOG_ERROR, "Could not get Display Mode Iterator\n");
+        ctx->dl->Release();
+        return AVERROR(EIO);
+    }
+
     /* Setup streams. */
     for (n = 0; n < avctx->nb_streams; n++) {
         AVStream *st = avctx->streams[n];
@@ -557,7 +395,7 @@ av_cold int ff_decklink_write_header(AVFormatContext *avctx)
             goto error;
         }
     }
-    ctx->itermode->Release();
+    itermode->Release();
 
     return 0;
 
diff --git a/libavdevice/decklink_enc.h b/libavdevice/decklink_enc.h
index 0b9ad8f79e..6086947e6c 100644
--- a/libavdevice/decklink_enc.h
+++ b/libavdevice/decklink_enc.h
@@ -19,17 +19,6 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-struct decklink_cctx {
-    const AVClass *cclass;
-
-    void *ctx;
-
-    /* Options */
-    int list_devices;
-    int list_formats;
-    double preroll;
-};
-
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/libavdevice/decklink_enc_c.c b/libavdevice/decklink_enc_c.c
index 7c1804376a..c3c90184f8 100644
--- a/libavdevice/decklink_enc_c.c
+++ b/libavdevice/decklink_enc_c.c
@@ -22,6 +22,7 @@
 #include "libavformat/avformat.h"
 #include "libavutil/opt.h"
 
+#include "decklink_common_c.h"
 #include "decklink_enc.h"
 
 #define OFFSET(x) offsetof(struct decklink_cctx, x)