working on avi parsers

data/formats/avi/Demuxer.h

@@ -0,0 +1,158 @@
+#pragma once
+
+#include "structs.h"
+
+// https://docs.microsoft.com/en-us/previous-versions//ms779636(v=vs.85)?redirectedfrom=MSDN
+namespace AVI {
+
+	template <typename Source> class Demuxer {
+
+		Source& src;
+
+		bool valid = true;
+		AVITypeHeader riff;
+		AVITypeHeader hdrl;
+		AVICommonHeader avih;
+		AVIMainHeader main_hdr;
+
+		struct State {
+
+			AVIStreamHeader streamHeaders[2];
+
+			struct Video {
+				uint32_t streamID;
+				BitMapInfoHeader fmt;
+			} video;
+
+			struct Audio {
+				uint32_t streamID;
+				WaveFormat fmt;
+			} audio;
+
+			ChunkInfo moviInfo;
+			ChunkInfo idxlInfo;
+
+			uint32_t totalSec;
+
+		} state;
+
+	public:
+
+		Demuxer(Source& src) : src(src) {
+
+			read(riff);
+			if (memcmp(riff.fourcc, "RIFF", 4) != 0)	{valid = false; return;}
+
+			read(hdrl);
+			if (memcmp(hdrl.fourcc, "LIST", 4) != 0)	{valid = false; return;}
+			if (memcmp(hdrl.type,   "hdrl", 4) != 0)	{valid = false; return;}
+
+			read(avih);
+			if (memcmp(avih.fourcc, "avih", 4) != 0)	{valid = false; return;}
+			if (avih.length != sizeof(main_hdr))		{valid = false; return;}
+
+			read(main_hdr);
+
+			uint32_t posOfStreamStart = pos;
+
+			for (uint32_t i = 0; i < main_hdr.streams; ++i) {
+
+				bool curStreamIsVideo = false;
+
+				AVITypeHeader strl;
+				read(strl);
+				if (memcmp(strl.fourcc, "LIST", 4) != 0)	{valid = false; return;}
+				if (memcmp(strl.type,   "strl", 4) != 0)	{valid = false; return;}
+
+				AVICommonHeader strh;
+				read(strh);
+				if (memcmp(strh.fourcc,   "strh", 4) != 0)	{valid = false; return;}
+
+				AVIStreamHeader stream_hdr;
+				read(stream_hdr);
+				if			(memcmp(stream_hdr.type, "vids", 4) == 0) {
+					state.video.streamID = i;
+					state.streamHeaders[i] = stream_hdr;
+					curStreamIsVideo = true;
+				} else if	(memcmp(stream_hdr.type, "auds", 4) == 0) {
+					state.audio.streamID = i;
+					state.streamHeaders[i] = stream_hdr;
+				} else {
+					valid = false; return;
+				}
+
+				AVICommonHeader strf;
+				read(strf);
+				if (curStreamIsVideo) {
+					BitMapInfoHeader bmih;
+					read(bmih);
+					state.video.fmt = bmih;
+				} else {
+					WaveFormat wf;
+					read(state.audio.fmt);
+				}
+
+				// seek to the next stream
+				seek(posOfStreamStart + 8 + strl.length);
+
+			}
+
+			AVITypeHeader movi;
+			state.moviInfo.offset = pos;
+			read(movi);
+			state.moviInfo.entry_offset = pos;
+			state.moviInfo.size = movi.length - 4;
+
+			seek(state.moviInfo.offset + 8 + movi.length);
+
+			AVITypeHeader idxl;
+			state.idxlInfo.offset = pos;
+			read(idxl);
+			state.idxlInfo.entry_offset = pos;
+			state.idxlInfo.size = idxl.length - 4;
+
+			// total length in seconds based on the video stream
+			// normally scale is 1 and rate = FPS
+			// for non-integer FPS, scale and rate vary accordingly
+			AVIStreamHeader& videoStreamHeader = state.streamHeaders[state.video.streamID];
+			state.totalSec = videoStreamHeader.length * videoStreamHeader.scale / videoStreamHeader.rate;
+
+			printf("nn");
+			//	p->total_sec = avi_video_calc_seconds(avi_parser_get_video_header(p));
+			//	goto end;
+
+
+
+			//seek(state.streamHeaders[state.video.streamID].start);
+			AVICommonHeader chead;
+			read(chead);
+
+			printf("nn");
+
+		}
+
+		bool isValid() const {
+			return valid;
+		}
+
+	private:
+
+		uint32_t pos = 0;
+
+		void seek(uint32_t newPos) {
+			pos = newPos;
+		}
+
+		template <typename T> void read(T& dst) {
+			read(sizeof(T), &dst);
+		}
+
+		/** read x bytes from the input into dst */
+		template <typename T> void read(uint32_t size, T* dst) {
+			src.read(pos, size, (uint8_t*)dst);
+			pos += size;
+		}
+
+	};
+
+}