參考文件ISO13181-1.pdf

解析TS流的第一個步驟就是解析出TS的包長與開始位置資訊。包的長度有188位元組和204位元組之分，而每一個packet的開頭都是0x47。

下圖是packet的結構體：

packet結構體解析，解packet長度是解析TS流的開始，不需要知道其他結構體成員的介紹。（本人只做了關鍵點的標誌）：

1：sync_byte –The sync_byte is a fixed 8-bit field whose value is '0100 0111' (0x47). Sync_byte emulation in the choice
of values for other regularly occurring fields, such as PID, should be avoided.

那麼當我們fopen開啟TS檔案時，如何確定當前TS的包長以及第一個有效包的位置資訊呢？由結構體資訊我們知道packet的首位元組必定是0x47，所有當我們讀取到資料是0x47時就有兩種情況，要麼這個0x47是包的同步位元組要麼不是。假如是包的同步位元組，當我們偏移包長（188或者204）之後再取值資料應該還是0x47。所有我們往後判斷十次，如果每一次偏移之後取得的值都是0x47的話說明這個位置就是第一個有效包的位置。

程式有不足之處，希望大家能夠指正出來。

int main(int argc, char *argv[])
{	
	errno_t err;
	FILE *pfTsFile = NULL;
	err = fopen_s(&pfTsFile, argv[1], "rb");
	if (err != 0)
	{
		perror("fopen .ts error!");
		return -1;
	}

	int iReturn = ParseTs(pfTsFile);

	fclose(pfTsFile);
	return iReturn;
}

int ParseTs(FILE *pfTsFile)
{
	int iTsLength = 0;
	int iTsPosition = 0;
	int iReturn = 0;

	iTsLength = ParseTsLength(pfTsFile, &iTsPosition);	
	printf("\nThe transport stream packet length is: %d\n", iTsLength);
	printf("and the first packet position is: %d\n\n", iTsPosition);

	return iReturn;
}

int ParseTsLength(FILE *pfTsFile, int *piTsPosition)
{
	char cPacketByte = 0;
	int uiPacketLength = 0;

	while ((cPacketByte = fgetc(pfTsFile)) != EOF)
	{
		if (cPacketByte == 0x47)
		{
			//printf("\nfind first ox47 in position: %d, whether the length is 188?\n",*piTsPosition);
			if (JudgmentPacketLength(pfTsFile, *piTsPosition, 188) == 188)
			{
				uiPacketLength = 188;
				goto Ret;
			}

			//printf("nfind length is no 188, whether the length is 204?\n");
			if (JudgmentPacketLength(pfTsFile, *piTsPosition, 204) == 204)
			{
				uiPacketLength = 204;
				goto Ret;
			}
		}

		//Move the cursor to the next one
		(*piTsPosition)++;
		if (fseek(pfTsFile, *piTsPosition, SEEK_SET) == -1)
		{
			perror("fseek error");
			uiPacketLength = -1;
			goto Ret;
		}
	}

	printf("This .ts file have no the transport stream.\n");
	uiPacketLength = -1;

Ret:
	return uiPacketLength;
}

static int JudgmentPacketLength(FILE *pfTsFile, int iTsPosition, int iLength)
{
	int iTime = 0;
	int iPacketByte = 0;

	if (fseek(pfTsFile, iTsPosition + 1, SEEK_SET) == -1)
	{
		printf("fseek in %d error\n", iTsPosition + 1);
		iLength = -1;
		goto Ret;
	}

	for (iTime = 0; iTime<10; iTime++)
	{
		if (fseek(pfTsFile, iLength - 1, SEEK_CUR) == -1)
		{
			printf("fseek %d error\n", iLength);
			iLength = -1;
			goto Ret;
		}
		
		if ((iPacketByte = fgetc(pfTsFile)) == EOF)
		{
			printf("after fseek %d feof\n", iLength);
			iLength = -1;
			goto Ret;
		}

		if (iPacketByte != 0x47)
		{
			//printf("Is no transport stream packet.\n");
			iLength = -1;
			goto Ret;
		}
	}

Ret:
	return iLength;
}
 

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