From 79e9bca11f53208b09d7b62cfb93d44baaa52374 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kamil=20Trzci=C5=84ski?= <ayufan@ayufan.eu>
Date: Sat, 29 Oct 2022 11:36:58 +0200
Subject: [PATCH] Discover H264 keyframes on dequeue

---
 device/buffer_queue.c   | 23 +++++++++++++++++++++++
 output/http_ffmpeg.c    |  2 +-
 output/http_h264.c      | 23 +----------------------
 output/output.h         |  1 -
 output/rtsp/rtsp.cc     |  2 +-
 output/webrtc/webrtc.cc |  2 +-
 6 files changed, 27 insertions(+), 26 deletions(-)

diff --git a/device/buffer_queue.c b/device/buffer_queue.c
index 38c4071..de9fd51 100644
--- a/device/buffer_queue.c
+++ b/device/buffer_queue.c
@@ -2,6 +2,7 @@
 #include "device/buffer_list.h"
 #include "device/device.h"
 #include "util/opts/log.h"
+#include "util/opts/fourcc.h"
 
 #include <pthread.h>
 #include <inttypes.h>
@@ -144,6 +145,24 @@ int buffer_list_enqueue(buffer_list_t *buf_list, buffer_t *dma_buf)
   return 1;
 }
 
+static void buffer_update_h264_key_frame(buffer_t *buf)
+{
+  unsigned char *data = buf->start;
+
+  static const int N = 8;
+  char buffer [3*N+1];
+  buffer[sizeof(buffer)-1] = 0;
+  for(int j = 0; j < N; j++)
+    sprintf(&buffer[sizeof(buffer)/N*j], "%02X ", data[j]);
+
+  if (buf->flags.is_keyframe) {
+    LOG_DEBUG(buf, "Got key frame (from V4L2)!: %s", buffer);
+  } else if (buf->used >= 5 && (data[4] & 0x1F) == 0x07) {
+    LOG_DEBUG(buf, "Got key frame (from buffer)!: %s", buffer);
+    buf->flags.is_keyframe = true;
+  }
+}
+
 buffer_t *buffer_list_dequeue(buffer_list_t *buf_list)
 {
   buffer_t *buf = NULL;
@@ -174,6 +193,10 @@ buffer_t *buffer_list_dequeue(buffer_list_t *buf_list)
     buf->dma_source = NULL;
   }
 
+  if (buf_list->fmt.format == V4L2_PIX_FMT_H264) {
+    buffer_update_h264_key_frame(buf);
+  }
+
   buf_list->frames++;
   return buf;
 
diff --git a/output/http_ffmpeg.c b/output/http_ffmpeg.c
index c66b256..1336346 100644
--- a/output/http_ffmpeg.c
+++ b/output/http_ffmpeg.c
@@ -77,7 +77,7 @@ static int http_ffmpeg_write_to_stream(void *opaque, uint8_t *buf, int buf_size)
 static int http_ffmpeg_video_buf_part(buffer_lock_t *buf_lock, buffer_t *buf, int frame, http_ffmpeg_status_t *status)
 {
   if (!status->had_key_frame) {
-    status->had_key_frame = h264_is_key_frame(buf);
+    status->had_key_frame = buf->flags.is_keyframe;
   }
 
   if (!status->had_key_frame) {
diff --git a/output/http_h264.c b/output/http_h264.c
index 52d62b4..90a8a3a 100644
--- a/output/http_h264.c
+++ b/output/http_h264.c
@@ -31,31 +31,10 @@ typedef struct {
   bool requested_key_frame;
 } http_video_status_t;
 
-bool h264_is_key_frame(buffer_t *buf)
-{
-  unsigned char *data = buf->start;
-
-  static const int N = 8;
-  char buffer [3*N+1];
-  buffer[sizeof(buffer)-1] = 0;
-  for(int j = 0; j < N; j++)
-    sprintf(&buffer[sizeof(buffer)/N*j], "%02X ", data[j]);
-
-  if (buf->flags.is_keyframe) {
-    LOG_DEBUG(buf, "Got key frame (from V4L2)!: %s", buffer);
-    return true;
-  } else if (buf->used >= 5 && (data[4] & 0x1F) == 0x07) {
-    LOG_DEBUG(buf, "Got key frame (from buffer)!: %s", buffer);
-    return true;
-  }
-
-  return false;
-}
-
 int http_video_buf_part(buffer_lock_t *buf_lock, buffer_t *buf, int frame, http_video_status_t *status)
 {
   if (!status->had_key_frame) {
-    status->had_key_frame = h264_is_key_frame(buf);
+    status->had_key_frame = buf->flags.is_keyframe;
   }
 
   if (!status->had_key_frame) {
diff --git a/output/output.h b/output/output.h
index 42ae185..6b98e44 100644
--- a/output/output.h
+++ b/output/output.h
@@ -17,7 +17,6 @@ void http_stream(struct http_worker_s *worker, FILE *stream);
 void http_option(struct http_worker_s *worker, FILE *stream);
 
 // H264
-bool h264_is_key_frame(struct buffer_s *buf);
 void http_h264_video(struct http_worker_s *worker, FILE *stream);
 void http_mkv_video(struct http_worker_s *worker, FILE *stream);
 void http_mp4_video(struct http_worker_s *worker, FILE *stream);
diff --git a/output/rtsp/rtsp.cc b/output/rtsp/rtsp.cc
index e3511ca..404cc46 100644
--- a/output/rtsp/rtsp.cc
+++ b/output/rtsp/rtsp.cc
@@ -75,7 +75,7 @@ public:
       return;
     }
 
-    if (h264_is_key_frame(buf)) {
+    if (buf->flags.is_keyframe) {
       fHadKeyFrame = true;
     }
 
diff --git a/output/webrtc/webrtc.cc b/output/webrtc/webrtc.cc
index c50fd58..f4df590 100644
--- a/output/webrtc/webrtc.cc
+++ b/output/webrtc/webrtc.cc
@@ -115,7 +115,7 @@ public:
     }
 
     if (!had_key_frame) {
-      if (!h264_is_key_frame(buf)) {
+      if (!buf->flags.is_keyframe) {
         device_video_force_key(buf->buf_list->dev);
         LOG_VERBOSE(self, "Skipping as key frame was not yet sent.");
         return;