fix: add FFmpeg 5.0 compatibility for AVFrame::duration

AVFrame::duration was added in FFmpeg 5.1 (libavutil 57.28.100).
For FFmpeg 5.0, use the deprecated pkt_duration field instead.

Added AV_FRAME_DURATION and AV_FRAME_SET_DURATION macros in common.h
that select the correct field based on FFmpeg version.

Author: pproenca

src/common.h

@@ -26,6 +26,16 @@ extern "C" {
 #error "FFmpeg 5.0+ (libavcodec 59+) is required"
 #endif
 
+// AVFrame::duration was added in FFmpeg 5.1 (libavutil 57.28.100)
+// Before that, use pkt_duration (deprecated in 5.1+)
+#if LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(57, 28, 100)
+#define AV_FRAME_DURATION(frame) ((frame)->duration)
+#define AV_FRAME_SET_DURATION(frame, val) ((frame)->duration = (val))
+#else
+#define AV_FRAME_DURATION(frame) ((frame)->pkt_duration)
+#define AV_FRAME_SET_DURATION(frame, val) ((frame)->pkt_duration = (val))
+#endif
+
 namespace webcodecs {
 
 //==============================================================================

src/image_decoder.cc

@@ -546,8 +546,8 @@ bool ImageDecoder::ParseAnimatedImageMetadata() {
 
             // Duration from packet or frame
             int64_t duration = pkt->duration;
-            if (duration <= 0 && frm->duration > 0) {
-              duration = frm->duration;
+            if (duration <= 0 && AV_FRAME_DURATION(frm.get()) > 0) {
+              duration = AV_FRAME_DURATION(frm.get());
             }
             if (duration > 0) {
               decoded_frame.duration =

src/video_encoder.cc

@@ -526,7 +526,7 @@ Napi::Value VideoEncoder::Encode(const Napi::CallbackInfo& info) {
   frame->height = video_frame->GetHeight();
   frame->format = AV_PIX_FMT_RGBA;
   frame->pts = video_frame->GetTimestampValue();
-  frame->duration = video_frame->GetDurationValue();
+  AV_FRAME_SET_DURATION(frame.get(), video_frame->GetDurationValue());
 
   // Copy RGBA data
   size_t data_size = frame->width * frame->height * kBytesPerPixelRgba;

src/video_encoder_worker.cc

@@ -341,7 +341,7 @@ void VideoEncoderWorker::OnEncode(const EncodeMessage& msg) {
   int src_width = src_frame->width;
   int src_height = src_frame->height;
   int64_t timestamp = src_frame->pts;
-  int64_t duration = src_frame->duration;
+  int64_t duration = AV_FRAME_DURATION(src_frame);
 
   // For RGBA input, convert to YUV420P
   // The source frame contains RGBA data packed in data[0]