WebSVN - shark - Blame - Rev 1625 - /advdemos/trunk/fsf/mpeg2/getvlc.c

Rev	Author	Line No.	Line
1624	giacomo	1	/* getvlc.c, variable length decoding */
		2
		3	/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
		4
		5	/*
		6	* Disclaimer of Warranty
		7	*
		8	* These software programs are available to the user without any license fee or
		9	* royalty on an "as is" basis. The MPEG Software Simulation Group disclaims
		10	* any and all warranties, whether express, implied, or statuary, including any
		11	* implied warranties or merchantability or of fitness for a particular
		12	* purpose. In no event shall the copyright-holder be liable for any
		13	* incidental, punitive, or consequential damages of any kind whatsoever
		14	* arising from the use of these programs.
		15	*
		16	* This disclaimer of warranty extends to the user of these programs and user's
		17	* customers, employees, agents, transferees, successors, and assigns.
		18	*
		19	* The MPEG Software Simulation Group does not represent or warrant that the
		20	* programs furnished hereunder are free of infringement of any third-party
		21	* patents.
		22	*
		23	* Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
		24	* are subject to royalty fees to patent holders. Many of these patents are
		25	* general enough such that they are unavoidable regardless of implementation
		26	* design.
		27	*
		28	*/
		29
		30	#include "config.h"
		31	#include "global.h"
		32	#include "getvlc.h"
		33
		34	/* private prototypes */
		35	/* generic picture macroblock type processing functions */
		36	static int Get_I_macroblock_type _ANSI_ARGS_((void));
		37	static int Get_P_macroblock_type _ANSI_ARGS_((void));
		38	static int Get_B_macroblock_type _ANSI_ARGS_((void));
		39	static int Get_D_macroblock_type _ANSI_ARGS_((void));
		40
		41	/* spatial picture macroblock type processing functions */
		42	static int Get_I_Spatial_macroblock_type _ANSI_ARGS_((void));
		43	static int Get_P_Spatial_macroblock_type _ANSI_ARGS_((void));
		44	static int Get_B_Spatial_macroblock_type _ANSI_ARGS_((void));
		45	static int Get_SNR_macroblock_type _ANSI_ARGS_((void));
		46
		47	int Get_macroblock_type()
		48	{
		49	int macroblock_type = 0;
		50
		51	if (ld->scalable_mode==SC_SNR)
		52	macroblock_type = Get_SNR_macroblock_type();
		53	else
		54	{
		55	switch (picture_coding_type)
		56	{
		57	case I_TYPE:
		58	macroblock_type = ld->pict_scal ? Get_I_Spatial_macroblock_type() : Get_I_macroblock_type();
		59	break;
		60	case P_TYPE:
		61	macroblock_type = ld->pict_scal ? Get_P_Spatial_macroblock_type() : Get_P_macroblock_type();
		62	break;
		63	case B_TYPE:
		64	macroblock_type = ld->pict_scal ? Get_B_Spatial_macroblock_type() : Get_B_macroblock_type();
		65	break;
		66	case D_TYPE:
		67	macroblock_type = Get_D_macroblock_type();
		68	break;
		69	default:
		70	cprintf("Get_macroblock_type(): unrecognized picture coding type\n");
		71	break;
		72	}
		73	}
		74
		75	return macroblock_type;
		76	}
		77
		78	static int Get_I_macroblock_type()
		79	{
		80	#ifdef TRACE
		81	if (Trace_Flag)
		82	cprintf("macroblock_type(I) ");
		83	#endif /* TRACE */
		84
		85	if (Get_Bits1())
		86	{
		87	#ifdef TRACE
		88	if (Trace_Flag)
		89	cprintf("(1): Intra (1)\n");
		90	#endif /* TRACE */
		91	return 1;
		92	}
		93
		94	if (!Get_Bits1())
		95	{
		96	if (!Quiet_Flag)
		97	cprintf("Invalid macroblock_type code\n");
		98	Fault_Flag = 1;
		99	}
		100
		101	#ifdef TRACE
		102	if (Trace_Flag)
		103	cprintf("(01): Intra, Quant (17)\n");
		104	#endif /* TRACE */
		105
		106	return 17;
		107	}
		108
		109	static char *MBdescr[]={
		110	"", "Intra", "No MC, Coded", "",
		111	"Bwd, Not Coded", "", "Bwd, Coded", "",
		112	"Fwd, Not Coded", "", "Fwd, Coded", "",
		113	"Interp, Not Coded", "", "Interp, Coded", "",
		114	"", "Intra, Quant", "No MC, Coded, Quant", "",
		115	"", "", "Bwd, Coded, Quant", "",
		116	"", "", "Fwd, Coded, Quant", "",
		117	"", "", "Interp, Coded, Quant", ""
		118	};
		119
		120	static int Get_P_macroblock_type()
		121	{
		122	int code;
		123
		124	#ifdef TRACE
		125	if (Trace_Flag)
		126	cprintf("macroblock_type(P) (");
		127	#endif /* TRACE */
		128
		129	if ((code = Show_Bits(6))>=8)
		130	{
		131	code >>= 3;
		132	Flush_Buffer(PMBtab0[code].len);
		133	#ifdef TRACE
		134	if (Trace_Flag)
		135	{
		136	Print_Bits(code,3,PMBtab0[code].len);
		137	cprintf("): %s (%d)\n",MBdescr[(int)PMBtab0[code].val],PMBtab0[code].val);
		138	}
		139	#endif /* TRACE */
		140	return PMBtab0[code].val;
		141	}
		142
		143	if (code==0)
		144	{
		145	if (!Quiet_Flag)
		146	cprintf("Invalid macroblock_type code\n");
		147	Fault_Flag = 1;
		148	return 0;
		149	}
		150
		151	Flush_Buffer(PMBtab1[code].len);
		152
		153	#ifdef TRACE
		154	if (Trace_Flag)
		155	{
		156	Print_Bits(code,6,PMBtab1[code].len);
		157	cprintf("): %s (%d)\n",MBdescr[(int)PMBtab1[code].val],PMBtab1[code].val);
		158	}
		159	#endif /* TRACE */
		160
		161	return PMBtab1[code].val;
		162	}
		163
		164	static int Get_B_macroblock_type()
		165	{
		166	int code;
		167
		168	#ifdef TRACE
		169	if (Trace_Flag)
		170	cprintf("macroblock_type(B) (");
		171	#endif /* TRACE */
		172
		173	if ((code = Show_Bits(6))>=8)
		174	{
		175	code >>= 2;
		176	Flush_Buffer(BMBtab0[code].len);
		177
		178	#ifdef TRACE
		179	if (Trace_Flag)
		180	{
		181	Print_Bits(code,4,BMBtab0[code].len);
		182	cprintf("): %s (%d)\n",MBdescr[(int)BMBtab0[code].val],BMBtab0[code].val);
		183	}
		184	#endif /* TRACE */
		185
		186	return BMBtab0[code].val;
		187	}
		188
		189	if (code==0)
		190	{
		191	if (!Quiet_Flag)
		192	cprintf("Invalid macroblock_type code\n");
		193	Fault_Flag = 1;
		194	return 0;
		195	}
		196
		197	Flush_Buffer(BMBtab1[code].len);
		198
		199	#ifdef TRACE
		200	if (Trace_Flag)
		201	{
		202	Print_Bits(code,6,BMBtab1[code].len);
		203	cprintf("): %s (%d)\n",MBdescr[(int)BMBtab1[code].val],BMBtab1[code].val);
		204	}
		205	#endif /* TRACE */
		206
		207	return BMBtab1[code].val;
		208	}
		209
		210	static int Get_D_macroblock_type()
		211	{
		212	if (!Get_Bits1())
		213	{
		214	if (!Quiet_Flag)
		215	cprintf("Invalid macroblock_type code\n");
		216	Fault_Flag=1;
		217	}
		218
		219	return 1;
		220	}
		221
		222	/* macroblock_type for pictures with spatial scalability */
		223	static int Get_I_Spatial_macroblock_type()
		224	{
		225	int code;
		226
		227	#ifdef TRACE
		228	if (Trace_Flag)
		229	cprintf("macroblock_type(I,spat) (");
		230	#endif /* TRACE */
		231
		232	code = Show_Bits(4);
		233
		234	if (code==0)
		235	{
		236	if (!Quiet_Flag)
		237	cprintf("Invalid macroblock_type code\n");
		238	Fault_Flag = 1;
		239	return 0;
		240	}
		241
		242	#ifdef TRACE
		243	if (Trace_Flag)
		244	{
		245	Print_Bits(code,4,spIMBtab[code].len);
		246	cprintf("): %02x\n",spIMBtab[code].val);
		247	}
		248	#endif /* TRACE */
		249
		250	Flush_Buffer(spIMBtab[code].len);
		251	return spIMBtab[code].val;
		252	}
		253
		254	static int Get_P_Spatial_macroblock_type()
		255	{
		256	int code;
		257
		258	#ifdef TRACE
		259	if (Trace_Flag)
		260	cprintf("macroblock_type(P,spat) (");
		261	#endif /* TRACE */
		262
		263	code = Show_Bits(7);
		264
		265	if (code<2)
		266	{
		267	if (!Quiet_Flag)
		268	cprintf("Invalid macroblock_type code\n");
		269	Fault_Flag = 1;
		270	return 0;
		271	}
		272
		273	if (code>=16)
		274	{
		275	code >>= 3;
		276	Flush_Buffer(spPMBtab0[code].len);
		277
		278	#ifdef TRACE
		279	if (Trace_Flag)
		280	{
		281	Print_Bits(code,4,spPMBtab0[code].len);
		282	cprintf("): %02x\n",spPMBtab0[code].val);
		283	}
		284	#endif /* TRACE */
		285
		286	return spPMBtab0[code].val;
		287	}
		288
		289	Flush_Buffer(spPMBtab1[code].len);
		290
		291	#ifdef TRACE
		292	if (Trace_Flag)
		293	{
		294	Print_Bits(code,7,spPMBtab1[code].len);
		295	cprintf("): %02x\n",spPMBtab1[code].val);
		296	}
		297	#endif /* TRACE */
		298
		299	return spPMBtab1[code].val;
		300	}
		301
		302	static int Get_B_Spatial_macroblock_type()
		303	{
		304	int code;
		305	VLCtab *p;
		306
		307	#ifdef TRACE
		308	if (Trace_Flag)
		309	cprintf("macroblock_type(B,spat) (");
		310	#endif /* TRACE */
		311
		312	code = Show_Bits(9);
		313
		314	if (code>=64)
		315	p = &spBMBtab0[(code>>5)-2];
		316	else if (code>=16)
		317	p = &spBMBtab1[(code>>2)-4];
		318	else if (code>=8)
		319	p = &spBMBtab2[code-8];
		320	else
		321	{
		322	if (!Quiet_Flag)
		323	cprintf("Invalid macroblock_type code\n");
		324	Fault_Flag = 1;
		325	return 0;
		326	}
		327
		328	Flush_Buffer(p->len);
		329
		330	#ifdef TRACE
		331	if (Trace_Flag)
		332	{
		333	Print_Bits(code,9,p->len);
		334	printf("): %02x\n",p->val);
		335	}
		336	#endif /* TRACE */
		337
		338	return p->val;
		339	}
		340
		341	static int Get_SNR_macroblock_type()
		342	{
		343	int code;
		344
		345	#ifdef TRACE /* CH */
		346	if (Trace_Flag)
		347	cprintf("macroblock_type(SNR) (");
		348	#endif
		349
		350	code = Show_Bits(3);
		351
		352	if (code==0)
		353	{
		354	if (!Quiet_Flag)
		355	cprintf("Invalid macroblock_type code\n");
		356	Fault_Flag = 1;
		357	return 0;
		358	}
		359
		360	Flush_Buffer(SNRMBtab[code].len);
		361
		362	#ifdef TRACE /* CH */
		363	if (Trace_Flag)
		364	{
		365	Print_Bits(code,3,SNRMBtab[code].len);
		366	cprintf("): %s (%d)\n",MBdescr[(int)SNRMBtab[code].val],SNRMBtab[code].val);
		367	}
		368	#endif
		369
		370
		371	return SNRMBtab[code].val;
		372	}
		373
		374	int Get_motion_code()
		375	{
		376	int code;
		377
		378	#ifdef TRACE
		379	if (Trace_Flag)
		380	cprintf("motion_code (");
		381	#endif /* TRACE */
		382
		383	if (Get_Bits1())
		384	{
		385	#ifdef TRACE
		386	if (Trace_Flag)
		387	cprintf("0): 0\n");
		388	#endif /* TRACE */
		389	return 0;
		390	}
		391
		392	if ((code = Show_Bits(9))>=64)
		393	{
		394	code >>= 6;
		395	Flush_Buffer(MVtab0[code].len);
		396
		397	#ifdef TRACE
		398	if (Trace_Flag)
		399	{
		400	Print_Bits(code,3,MVtab0[code].len);
		401	cprintf("%d): %d\n",
		402	Show_Bits(1),Show_Bits(1)?-MVtab0[code].val:MVtab0[code].val);
		403	}
		404	#endif /* TRACE */
		405
		406	return Get_Bits1()?-MVtab0[code].val:MVtab0[code].val;
		407	}
		408
		409	if (code>=24)
		410	{
		411	code >>= 3;
		412	Flush_Buffer(MVtab1[code].len);
		413
		414	#ifdef TRACE
		415	if (Trace_Flag)
		416	{
		417	Print_Bits(code,6,MVtab1[code].len);
		418	cprintf("%d): %d\n",
		419	Show_Bits(1),Show_Bits(1)?-MVtab1[code].val:MVtab1[code].val);
		420	}
		421	#endif /* TRACE */
		422
		423	return Get_Bits1()?-MVtab1[code].val:MVtab1[code].val;
		424	}
		425
		426	if ((code-=12)<0)
		427	{
		428	if (!Quiet_Flag)
		429	/* HACK */
		430	cprintf("Invalid motion_vector code (MBA %d, pic %d)\n", global_MBA, global_pic);
		431	Fault_Flag=1;
		432	return 0;
		433	}
		434
		435	Flush_Buffer(MVtab2[code].len);
		436
		437	#ifdef TRACE
		438	if (Trace_Flag)
		439	{
		440	Print_Bits(code+12,9,MVtab2[code].len);
		441	cprintf("%d): %d\n",
		442	Show_Bits(1),Show_Bits(1)?-MVtab2[code].val:MVtab2[code].val);
		443	}
		444	#endif /* TRACE */
		445
		446	return Get_Bits1() ? -MVtab2[code].val : MVtab2[code].val;
		447	}
		448
		449	/* get differential motion vector (for dual prime prediction) */
		450	int Get_dmvector()
		451	{
		452	#ifdef TRACE
		453	if (Trace_Flag)
		454	cprintf("dmvector (");
		455	#endif /* TRACE */
		456
		457	if (Get_Bits(1))
		458	{
		459	#ifdef TRACE
		460	if (Trace_Flag)
		461	cprintf(Show_Bits(1) ? "11): -1\n" : "10): 1\n");
		462	#endif /* TRACE */
		463	return Get_Bits(1) ? -1 : 1;
		464	}
		465	else
		466	{
		467	#ifdef TRACE
		468	if (Trace_Flag)
		469	cprintf("0): 0\n");
		470	#endif /* TRACE */
		471	return 0;
		472	}
		473	}
		474
		475	int Get_coded_block_pattern()
		476	{
		477	int code;
		478
		479	#ifdef TRACE
		480	if (Trace_Flag)
		481	cprintf("coded_block_pattern_420 (");
		482	#endif /* TRACE */
		483
		484	if ((code = Show_Bits(9))>=128)
		485	{
		486	code >>= 4;
		487	Flush_Buffer(CBPtab0[code].len);
		488
		489	#ifdef TRACE
		490	if (Trace_Flag)
		491	{
		492	Print_Bits(code,5,CBPtab0[code].len);
		493	cprintf("): ");
		494	Print_Bits(CBPtab0[code].val,6,6);
		495	cprintf(" (%d)\n",CBPtab0[code].val);
		496	}
		497	#endif /* TRACE */
		498
		499	return CBPtab0[code].val;
		500	}
		501
		502	if (code>=8)
		503	{
		504	code >>= 1;
		505	Flush_Buffer(CBPtab1[code].len);
		506
		507	#ifdef TRACE
		508	if (Trace_Flag)
		509	{
		510	Print_Bits(code,8,CBPtab1[code].len);
		511	cprintf("): ");
		512	Print_Bits(CBPtab1[code].val,6,6);
		513	cprintf(" (%d)\n",CBPtab1[code].val);
		514	}
		515	#endif /* TRACE */
		516
		517	return CBPtab1[code].val;
		518	}
		519
		520	if (code<1)
		521	{
		522	if (!Quiet_Flag)
		523	cprintf("Invalid coded_block_pattern code\n");
		524	Fault_Flag = 1;
		525	return 0;
		526	}
		527
		528	Flush_Buffer(CBPtab2[code].len);
		529
		530	#ifdef TRACE
		531	if (Trace_Flag)
		532	{
		533	Print_Bits(code,9,CBPtab2[code].len);
		534	cprintf("): ");
		535	Print_Bits(CBPtab2[code].val,6,6);
		536	cprintf(" (%d)\n",CBPtab2[code].val);
		537	}
		538	#endif /* TRACE */
		539
		540	return CBPtab2[code].val;
		541	}
		542
		543	int Get_macroblock_address_increment()
		544	{
		545	int code, val;
		546
		547	#ifdef TRACE
		548	if (Trace_Flag)
		549	cprintf("macroblock_address_increment (");
		550	#endif /* TRACE */
		551
		552	val = 0;
		553
		554	while ((code = Show_Bits(11))<24)
		555	{
		556	if (code!=15) /* if not macroblock_stuffing */
		557	{
		558	if (code==8) /* if macroblock_escape */
		559	{
		560	#ifdef TRACE
		561	if (Trace_Flag)
		562	cprintf("00000001000 ");
		563	#endif /* TRACE */
		564
		565	val+= 33;
		566	}
		567	else
		568	{
		569	if (!Quiet_Flag)
		570	cprintf("Invalid macroblock_address_increment code\n");
		571
		572	Fault_Flag = 1;
		573	return 1;
		574	}
		575	}
		576	else /* macroblock suffing */
		577	{
		578	#ifdef TRACE
		579	if (Trace_Flag)
		580	cprintf("00000001111 ");
		581	#endif /* TRACE */
		582	}
		583
		584	Flush_Buffer(11);
		585	}
		586
		587	/* macroblock_address_increment == 1 */
		588	/* ('1' is in the MSB position of the lookahead) */
		589	if (code>=1024)
		590	{
		591	Flush_Buffer(1);
		592	#ifdef TRACE
		593	if (Trace_Flag)
		594	cprintf("1): %d\n",val+1);
		595	#endif /* TRACE */
		596	return val + 1;
		597	}
		598
		599	/* codes 00010 ... 011xx */
		600	if (code>=128)
		601	{
		602	/* remove leading zeros */
		603	code >>= 6;
		604	Flush_Buffer(MBAtab1[code].len);
		605
		606	#ifdef TRACE
		607	if (Trace_Flag)
		608	{
		609	Print_Bits(code,5,MBAtab1[code].len);
		610	printf("): %d\n",val+MBAtab1[code].val);
		611	}
		612	#endif /* TRACE */
		613
		614
		615	return val + MBAtab1[code].val;
		616	}
		617
		618	/* codes 00000011000 ... 0000111xxxx */
		619	code-= 24; /* remove common base */
		620	Flush_Buffer(MBAtab2[code].len);
		621
		622	#ifdef TRACE
		623	if (Trace_Flag)
		624	{
		625	Print_Bits(code+24,11,MBAtab2[code].len);
		626	cprintf("): %d\n",val+MBAtab2[code].val);
		627	}
		628	#endif /* TRACE */
		629
		630	return val + MBAtab2[code].val;
		631	}
		632
		633	/* combined MPEG-1 and MPEG-2 stage. parse VLC and
		634	perform dct_diff arithmetic.
		635
		636	MPEG-1: ISO/IEC 11172-2 section
		637	MPEG-2: ISO/IEC 13818-2 section 7.2.1
		638
		639	Note: the arithmetic here is presented more elegantly than
		640	the spec, yet the results, dct_diff, are the same.
		641	*/
		642
		643	int Get_Luma_DC_dct_diff()
		644	{
		645	int code, size, dct_diff;
		646
		647	#ifdef TRACE
		648	/*
		649	if (Trace_Flag)
		650	printf("dct_dc_size_luminance: (");
		651	*/
		652	#endif /* TRACE */
		653
		654	/* decode length */
		655	code = Show_Bits(5);
		656
		657	if (code<31)
		658	{
		659	size = DClumtab0[code].val;
		660	Flush_Buffer(DClumtab0[code].len);
		661	#ifdef TRACE
		662	/*
		663	if (Trace_Flag)
		664	{
		665	Print_Bits(code,5,DClumtab0[code].len);
		666	printf("): %d",size);
		667	}
		668	*/
		669	#endif /* TRACE */
		670	}
		671	else
		672	{
		673	code = Show_Bits(9) - 0x1f0;
		674	size = DClumtab1[code].val;
		675	Flush_Buffer(DClumtab1[code].len);
		676
		677	#ifdef TRACE
		678	/*
		679	if (Trace_Flag)
		680	{
		681	Print_Bits(code+0x1f0,9,DClumtab1[code].len);
		682	printf("): %d",size);
		683	}
		684	*/
		685	#endif /* TRACE */
		686	}
		687
		688	#ifdef TRACE
		689	/*
		690	if (Trace_Flag)
		691	printf(", dct_dc_differential (");
		692	*/
		693	#endif /* TRACE */
		694
		695	if (size==0)
		696	dct_diff = 0;
		697	else
		698	{
		699	dct_diff = Get_Bits(size);
		700	#ifdef TRACE
		701	/*
		702	if (Trace_Flag)
		703	Print_Bits(dct_diff,size,size);
		704	*/
		705	#endif /* TRACE */
		706	if ((dct_diff & (1<<(size-1)))==0)
		707	dct_diff-= (1<<size) - 1;
		708	}
		709
		710	#ifdef TRACE
		711	/*
		712	if (Trace_Flag)
		713	printf("): %d\n",dct_diff);
		714	*/
		715	#endif /* TRACE */
		716
		717	return dct_diff;
		718	}
		719
		720
		721	int Get_Chroma_DC_dct_diff()
		722	{
		723	int code, size, dct_diff;
		724
		725	#ifdef TRACE
		726	/*
		727	if (Trace_Flag)
		728	printf("dct_dc_size_chrominance: (");
		729	*/
		730	#endif /* TRACE */
		731
		732	/* decode length */
		733	code = Show_Bits(5);
		734
		735	if (code<31)
		736	{
		737	size = DCchromtab0[code].val;
		738	Flush_Buffer(DCchromtab0[code].len);
		739
		740	#ifdef TRACE
		741	/*
		742	if (Trace_Flag)
		743	{
		744	Print_Bits(code,5,DCchromtab0[code].len);
		745	printf("): %d",size);
		746	}
		747	*/
		748	#endif /* TRACE */
		749	}
		750	else
		751	{
		752	code = Show_Bits(10) - 0x3e0;
		753	size = DCchromtab1[code].val;
		754	Flush_Buffer(DCchromtab1[code].len);
		755
		756	#ifdef TRACE
		757	/*
		758	if (Trace_Flag)
		759	{
		760	Print_Bits(code+0x3e0,10,DCchromtab1[code].len);
		761	printf("): %d",size);
		762	}
		763	*/
		764	#endif /* TRACE */
		765	}
		766
		767	#ifdef TRACE
		768	/*
		769	if (Trace_Flag)
		770	printf(", dct_dc_differential (");
		771	*/
		772	#endif /* TRACE */
		773
		774	if (size==0)
		775	dct_diff = 0;
		776	else
		777	{
		778	dct_diff = Get_Bits(size);
		779	#ifdef TRACE
		780	/*
		781	if (Trace_Flag)
		782	Print_Bits(dct_diff,size,size);
		783	*/
		784	#endif /* TRACE */
		785	if ((dct_diff & (1<<(size-1)))==0)
		786	dct_diff-= (1<<size) - 1;
		787	}
		788
		789	#ifdef TRACE
		790	/*
		791	if (Trace_Flag)
		792	printf("): %d\n",dct_diff);
		793	*/
		794	#endif /* TRACE */
		795
		796	return dct_diff;
		797	}

Subversion Repositories shark

(root)/advdemos/trunk/fsf/mpeg2/getvlc.c - Rev 1625