Reverting video_timestamp increment logic which used pkt.duration. In…

… some codecs (such as vp8), this approach breaks due to differences in the timebase vs the framerate. For example, if the timebase is an inverse of the FPS, everything works. But if the timebase is not, for example 1/1000000, this approach breaks.

src/FFmpegReader.cpp

@@ -768,12 +768,12 @@ void FFmpegReader::UpdateVideoInfo() {
 	// Check for valid duration (if found)
 	if (info.duration <= 0.0f && pFormatCtx->duration >= 0)
 		// Use the format's duration
-		info.duration = pFormatCtx->duration / AV_TIME_BASE;
+		info.duration = float(pFormatCtx->duration) / AV_TIME_BASE;
 
 	// Calculate duration from filesize and bitrate (if any)
 	if (info.duration <= 0.0f && info.video_bit_rate > 0 && info.file_size > 0)
 		// Estimate from bitrate, total bytes, and framerate
-		info.duration = (info.file_size / info.video_bit_rate);
+		info.duration = float(info.file_size) / info.video_bit_rate;
 
 	// No duration found in stream of file
 	if (info.duration <= 0.0f) {

src/FFmpegWriter.cpp

@@ -947,7 +947,7 @@ void FFmpegWriter::flush_encoders() {
             // Increment PTS by duration of packet
             audio_timestamp += pkt.duration;
 
-                    // deallocate memory for packet
+            // deallocate memory for packet
             AV_FREE_PACKET(&pkt);
         }
     }
@@ -1885,8 +1885,8 @@ void FFmpegWriter::write_audio_packets(bool is_final) {
             ZmqLogger::Instance()->AppendDebugMethod("FFmpegWriter::write_audio_packets ERROR [" + (std::string) av_err2str(error_code) + "]", "error_code", error_code);
         }
 
-        // Increment PTS by duration of packet
-        audio_timestamp += pkt.duration;
+        // Increment PTS (no pkt.duration, so calculate with maths)
+        audio_timestamp += FFMIN(audio_input_frame_size, audio_input_position);
 
         // deallocate AVFrame
         av_freep(&(frame_final->data[0]));
@@ -2134,9 +2134,6 @@ bool FFmpegWriter::write_video_packet(std::shared_ptr<Frame> frame, AVFrame *fra
 			}
 		}
 
-        // Increment PTS (in frames and scaled to the codec's timebase)
-        video_timestamp += pkt.duration;
-
 		// Deallocate packet
 		AV_FREE_PACKET(&pkt);
 #if USE_HW_ACCEL
@@ -2149,6 +2146,9 @@ bool FFmpegWriter::write_video_packet(std::shared_ptr<Frame> frame, AVFrame *fra
 #endif // USE_HW_ACCEL
 	}
 
+    // Increment PTS (in frames and scaled to the codec's timebase)
+    video_timestamp += av_rescale_q(1, av_make_q(info.fps.den, info.fps.num), video_codec_ctx->time_base);
+
 	// Success
 	return true;
 }