Merge pull request #3322 from embedded-ideas/master

Bufferless (on the fly) video data generation for the video device class

4 files changed, 93 insertions, 17 deletions

diff --git a/examples/device/video_capture/src/main.c b/examples/device/video_capture/src/main.c
index adcfb9f95..ffa2a7afa 100644
--- a/examples/device/video_capture/src/main.c
+++ b/examples/device/video_capture/src/main.c
@@ -56,6 +56,20 @@ void video_task(void* param);
 void freertos_init(void);
 #endif
 
+#if !defined(CFG_EXAMPLE_VIDEO_READONLY) || defined(CFG_EXAMPLE_VIDEO_BUFFERLESS)
+/* EBU color bars: https://stackoverflow.com/questions/6939422 */
+static uint8_t const bar_color[8][4] = {
+  /*  Y,   U,   Y,   V */
+  { 235, 128, 235, 128}, /* 100% White */
+  { 219,  16, 219, 138}, /* Yellow */
+  { 188, 154, 188,  16}, /* Cyan */
+  { 173,  42, 173,  26}, /* Green */
+  {  78, 214,  78, 230}, /* Magenta */
+  {  63, 102,  63, 240}, /* Red */
+  {  32, 240,  32, 118}, /* Blue */
+  {  16, 128,  16, 128}, /* Black */
+};
+#endif
 
 //--------------------------------------------------------------------+
 // Main
@@ -111,12 +125,43 @@ void tud_resume_cb(void) {
   blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
+#ifdef CFG_EXAMPLE_VIDEO_BUFFERLESS
+
+#ifndef CFG_EXAMPLE_VIDEO_DISABLE_MJPEG
+  #error Demo only supports YUV2 please define CFG_EXAMPLE_VIDEO_DISABLE_MJPEG
+#endif
+
+void tud_video_prepare_payload_cb(uint_fast8_t ctl_idx, uint_fast8_t stm_idx, tud_video_payload_request_t* request)
+{
+  static uint32_t frame_counter = 0;
+  (void)ctl_idx;
+  (void)stm_idx;
+
+  /* Offset will be zero at the start of a new frame */
+  if (!request->offset) frame_counter++;
+
+  for (size_t buf_pos = 0; buf_pos < request->length; buf_pos += 2) {
+
+    /* Position within the current line (pixel relative) */
+    int line_pos = ((request->offset + buf_pos)>>1) % FRAME_WIDTH;
+
+    /* Choose color based on the position and change the table offset every 4 frames */
+    const uint8_t* color = bar_color[(line_pos/(FRAME_WIDTH / 8) + (frame_counter>>2)) % 8];
+
+    /* Copy pixel data for odd or even pixels */
+    memcpy(&((uint8_t*)request->buf)[buf_pos], &color[(line_pos & 1) ? 2 : 0], 2);
+  }
+
+}
+#endif
+
 //--------------------------------------------------------------------+
 // USB Video
 //--------------------------------------------------------------------+
 static unsigned frame_num = 0;
 static unsigned tx_busy = 0;
 static unsigned interval_ms = 1000 / FRAME_RATE;
+#ifndef CFG_EXAMPLE_VIDEO_BUFFERLESS
 
 #ifdef CFG_EXAMPLE_VIDEO_READONLY
 // For mcus that does not have enough SRAM for frame buffer, we use fixed frame data.
@@ -145,18 +190,6 @@ static struct {
 static uint8_t frame_buffer[FRAME_WIDTH * FRAME_HEIGHT * 16 / 8];
 
 static void fill_color_bar(uint8_t* buffer, unsigned start_position) {
-  /* EBU color bars: https://stackoverflow.com/questions/6939422 */
-  static uint8_t const bar_color[8][4] = {
-      /*  Y,   U,   Y,   V */
-      { 235, 128, 235, 128}, /* 100% White */
-      { 219,  16, 219, 138}, /* Yellow */
-      { 188, 154, 188,  16}, /* Cyan */
-      { 173,  42, 173,  26}, /* Green */
-      {  78, 214,  78, 230}, /* Magenta */
-      {  63, 102,  63, 240}, /* Red */
-      {  32, 240,  32, 118}, /* Blue */
-      {  16, 128,  16, 128}, /* Black */
-  };
   uint8_t* p;
 
   /* Generate the 1st line */
@@ -183,6 +216,8 @@ static void fill_color_bar(uint8_t* buffer, unsigned start_position) {
 
 #endif
 
+#endif /* NDEF CFG_EXAMPLE_VIDEO_BUFFERLESS */
+
 static void video_send_frame(void) {
   static unsigned start_ms = 0;
   static unsigned already_sent = 0;
@@ -197,7 +232,9 @@ static void video_send_frame(void) {
     already_sent = 1;
     tx_busy = 1;
     start_ms = board_millis();
-#ifdef CFG_EXAMPLE_VIDEO_READONLY
+#if defined(CFG_EXAMPLE_VIDEO_BUFFERLESS)
+    tud_video_n_frame_xfer(0, 0, NULL, FRAME_WIDTH * FRAME_HEIGHT * 16 / 8);
+#elif defined (CFG_EXAMPLE_VIDEO_READONLY)
     #if defined(CFG_EXAMPLE_VIDEO_DISABLE_MJPEG)
     tud_video_n_frame_xfer(0, 0, (void*)(uintptr_t)&frame_buffer[(frame_num % (FRAME_WIDTH / 2)) * 4],
                            FRAME_WIDTH * FRAME_HEIGHT * 16/8);
@@ -220,7 +257,9 @@ static void video_send_frame(void) {
   start_ms += interval_ms;
   tx_busy = 1;
 
-#ifdef CFG_EXAMPLE_VIDEO_READONLY
+#if defined(CFG_EXAMPLE_VIDEO_BUFFERLESS)
+  tud_video_n_frame_xfer(0, 0, NULL, FRAME_WIDTH * FRAME_HEIGHT * 16 / 8);
+#elif defined(CFG_EXAMPLE_VIDEO_READONLY)
   #if defined(CFG_EXAMPLE_VIDEO_DISABLE_MJPEG)
   tud_video_n_frame_xfer(0, 0, (void*)(uintptr_t)&frame_buffer[(frame_num % (FRAME_WIDTH / 2)) * 4],
                          FRAME_WIDTH * FRAME_HEIGHT * 16/8);
diff --git a/examples/device/video_capture/src/tusb_config.h b/examples/device/video_capture/src/tusb_config.h
index 390152e16..1aa1a5ce7 100644
--- a/examples/device/video_capture/src/tusb_config.h
+++ b/examples/device/video_capture/src/tusb_config.h
@@ -110,6 +110,7 @@
 
 //#define CFG_EXAMPLE_VIDEO_READONLY
 //#define CFG_EXAMPLE_VIDEO_DISABLE_MJPEG
+//#define CFG_EXAMPLE_VIDEO_BUFFERLESS
 
 #ifdef __cplusplus
  }
diff --git a/src/class/video/video_device.c b/src/class/video/video_device.c
index 14eba86fb..844a5e672 100644
--- a/src/class/video/video_device.c
+++ b/src/class/video/video_device.c
@@ -214,6 +214,12 @@ TU_ATTR_WEAK int tud_video_commit_cb(uint_fast8_t ctl_idx, uint_fast8_t stm_idx,
   return VIDEO_ERROR_NONE;
 }
 
+TU_ATTR_WEAK void tud_video_prepare_payload_cb(uint_fast8_t ctl_idx, uint_fast8_t stm_idx, tud_video_payload_request_t* request) {
+  (void) ctl_idx;
+  (void) stm_idx;
+  (void) request;
+}
+
 //--------------------------------------------------------------------+
 //
 //--------------------------------------------------------------------+
@@ -874,7 +880,16 @@ static uint_fast16_t _prepare_in_payload(videod_streaming_interface_t *stm, uint
   }
   TU_ASSERT(pkt_len >= hdr_len);
   uint_fast16_t data_len = pkt_len - hdr_len;
-  memcpy(&ep_buf[hdr_len], stm->buffer + stm->offset, data_len);
+  if (stm->buffer) {
+    memcpy(&ep_buf[hdr_len], stm->buffer + stm->offset, data_len);
+  } else {
+    tud_video_payload_request_t rqst = {
+      .buf = &ep_buf[hdr_len],
+      .length = data_len,
+      .offset = stm->offset
+    };
+    tud_video_prepare_payload_cb(stm->index_vc, stm->index_vs, &rqst);
+  }
   stm->offset += data_len;
   remaining -= data_len;
   if (!remaining) {
@@ -1255,13 +1270,14 @@ bool tud_video_n_frame_xfer(uint_fast8_t ctl_idx, uint_fast8_t stm_idx, void *bu
   TU_ASSERT(ctl_idx < CFG_TUD_VIDEO);
   TU_ASSERT(stm_idx < CFG_TUD_VIDEO_STREAMING);
 
-  if (NULL == buffer || 0 == bufsize) {
+  if (0 == bufsize) {
     return false;
   }
+
   videod_streaming_interface_t *stm = _get_instance_streaming(ctl_idx, stm_idx);
   videod_streaming_epbuf_t *stm_epbuf = &_videod_streaming_epbuf[ctl_idx];
 
-  if (NULL == stm || 0 == stm->desc.ep[0] || stm->buffer) {
+  if (NULL == stm || 0 == stm->desc.ep[0] || stm->bufsize) {
     return false;
   }
   if (stm->state == VS_STATE_PROBING) {
diff --git a/src/class/video/video_device.h b/src/class/video/video_device.h
index 2b41c3bfe..f14555e4f 100644
--- a/src/class/video/video_device.h
+++ b/src/class/video/video_device.h
@@ -35,6 +35,16 @@
 extern "C" {
 #endif
 
+
+//--------------------------------------------------------------------+
+// Payload request
+//--------------------------------------------------------------------+
+typedef struct TU_ATTR_PACKED {
+    void* buf;      /* Payload buffer to be filled */
+    size_t length;  /* Length of the requested data in bytes */
+    size_t offset;  /* Offset within the frame (in bytes) */
+} tud_video_payload_request_t;
+
 //--------------------------------------------------------------------+
 // Application API (Multiple Ports)
 // CFG_TUD_VIDEO > 1
@@ -83,6 +93,16 @@ int tud_video_power_mode_cb(uint_fast8_t ctl_idx, uint8_t power_mod);
 int tud_video_commit_cb(uint_fast8_t ctl_idx, uint_fast8_t stm_idx,
                                      video_probe_and_commit_control_t const *parameters);
 
+/** Invoked if buffer is set to NULL (allows bufferless on the fly data generation)
+ *
+ * @param[in]   ctl_idx       Destination control interface index
+ * @param[in]   stm_idx       Destination streaming interface index
+ * @param[out]  payload_buf   Payload storage buffer (target buffer for requested data)
+ * @param[in]   payload_size  Size of payload_buf (requested data size)
+ * @param[in]   offset        Current byte offset relative to given bufsize from tud_video_n_frame_xfer (framesize)
+ * @return video_error_code_t */
+void tud_video_prepare_payload_cb(uint_fast8_t ctl_idx, uint_fast8_t stm_idx, tud_video_payload_request_t* request);
+
 //--------------------------------------------------------------------+
 // INTERNAL USBD-CLASS DRIVER API
 //--------------------------------------------------------------------+