aboutsummaryrefslogtreecommitdiffhomepage
path: root/divx4_vbr.c
blob: 467f77691016846de261f082e35fda0f5654fd6d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
/*
 *  divx4_vbr.c
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License. See the file COPYING in the main directory of the Linux
 *  distribution for more details.
 *
 *  2-pass code OpenDivX port:
 *  Copyright (C) 2001 Christoph Lampert <gruel@gmx.de> 
 *
 *  Large parts of this code were taken from VbrControl() from the OpenDivX
 *  project, (C) divxnetworks, written by Eugene Kuznetsov <ekuznetsov@divxnetworks.com>
 *  with the permission of Darrius "Junto" Thompson, Director DivX
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <math.h>
#include <inttypes.h>

#include "divx4_vbr.h"

#include "mp_msg.h"
#include "help_mp.h"

//#include "transcode.h"

#define FALSE 0
#define TRUE 1

/*  Absolute maximum and minimum quantizers used in VBR modes */
static const int min_quantizer=1;
static const int max_quantizer=31;

/*  Limits on frame-level deviation of quantizer ( higher values
	correspond to frames with more changes and vice versa ) */	
static const float min_quant_delta=-10.f;
static const float max_quant_delta=5.f;
/*  Limits on stream-level deviation of quantizer ( used to make
	overall bitrate of stream close to requested value ) */
static const float min_rc_quant_delta=.6f;
static const float max_rc_quant_delta=1.5f;

/*  Crispness parameter	controls threshold for decision whether
    to skip the frame or to code it. */
//static const float max_crispness=100.f;
/*	Maximum allowed number of skipped frames in a line. */
//static const int max_drops_line=0;					// CHL   We don't drop frames at the moment!


typedef struct entry_s
	/* max 28 bytes/frame or 5 Mb for 2-hour movie */
	{
		int quant;
		int text_bits;
		int motion_bits;
		int total_bits;
		float mult;
		short is_key_frame;
		short drop;
	} entry;

static int m_iCount;
static int m_iQuant;
/*static int m_iCrispness;*/
static short m_bDrop;
static float m_fQuant;

static int64_t m_lEncodedBits;
static int64_t m_lExpectedBits;

static FILE  *m_pFile;

static entry    vFrame;
static entry *m_vFrames;
static long	lFrameStart;

static int	iNumFrames;
static int	dummy;


void VbrControl_init_1pass_vbr(int quality, int crispness)
{
  m_fQuant=min_quantizer+((max_quantizer-min_quantizer)/6.)*(6-quality);
  m_iCount=0;
  m_bDrop=FALSE;
  VbrControl_update_1pass_vbr();
}

int VbrControl_init_2pass_vbr_analysis(const char *filename, int quality)
{
	m_pFile=fopen(filename, "wb");
	if(m_pFile==0)
		return -1;
	m_iCount=0;
	m_bDrop=FALSE;
	fprintf(m_pFile, "##version 1\n");
	fprintf(m_pFile, "quality %d\n", quality);
	return 0;
}

int VbrControl_init_2pass_vbr_encoding(const char *filename, int bitrate, double framerate, int crispness, int quality)
{
	int i;
	
	int64_t text_bits=0;
	int64_t total_bits=0;
	int64_t complexity=0;
	int64_t new_complexity=0;
	int64_t motion_bits=0;
	int64_t denominator=0;
	float qual_multiplier=1.;
	char head[20];

	int64_t desired_bits;
	int64_t non_text_bits;

	float average_complexity;

	m_pFile=fopen(filename, "rb");
	if(m_pFile==0)
		return -1;
	m_bDrop=FALSE;
	m_iCount=0;

	fread(head, 10, 1, m_pFile);
	if(!strncmp("##version ", head, 10))
	{
	    int version;
	    int iOldQual;
	    float old_qual, new_qual;
	    fscanf(m_pFile, "%d\n", &version);
	    fscanf(m_pFile, "quality %d\n", &iOldQual);
	    switch(iOldQual)
	    {
	    case 5:
		old_qual=1.f;
		break;
	    case 4:
		old_qual=1.1f;
		break;
	    case 3:
		old_qual=1.25f;
		break;
	    case 2:
		old_qual=1.4f;
		break;
	    case 1:
		old_qual=2.f;
		break;
	    }
	    switch(quality)
	    {
	    case 5:
		new_qual=1.f;
		break;
	    case 4:
		new_qual=1.1f;
		break;
	    case 3:
		new_qual=1.25f;
		break;
	    case 2:
		new_qual=1.4f;
		break;
	    case 1:
		new_qual=2.f;
		break;
	    }
	    qual_multiplier=new_qual/old_qual;	
	}
	else
	    fseek(m_pFile, 0, SEEK_SET);

	lFrameStart=ftell(m_pFile);		// save current position	

/* removed C++ dependencies, now read file twice :-( */

	
		while(!feof(m_pFile)) 
      {  fscanf(m_pFile, "Frame %d: intra %hd, quant %d, texture %d, motion %d, total %d\n",
         &iNumFrames, &(vFrame.is_key_frame), &(vFrame.quant), &(vFrame.text_bits), &(vFrame.motion_bits), &(vFrame.total_bits));

                vFrame.total_bits+=vFrame.text_bits*(qual_multiplier-1);
                vFrame.text_bits*=qual_multiplier;
                text_bits +=(int64_t)vFrame.text_bits;
					 motion_bits += (int64_t)vFrame.motion_bits;
                total_bits +=(int64_t)vFrame.total_bits;
                complexity +=(int64_t)vFrame.text_bits*vFrame.quant;

//	printf("Frames %d, texture %d, motion %d, quant %d total %d ",
//		iNumFrames, vFrame.text_bits, vFrame.motion_bits, vFrame.quant, vFrame.total_bits);
//	printf("texture %d, total %d, complexity %lld \n",vFrame.text_bits,vFrame.total_bits, complexity);
	 	}
		iNumFrames++;
		average_complexity=complexity/iNumFrames;
		
//		if (verbose & TC_DEBUG)	{
//		    fprintf(stderr, "(%s) frames %d, texture %lld, motion %lld, total %lld, complexity %lld\n", __FILE__, iNumFrames, text_bits, motion_bits, total_bits, complexity);
//		}
		
		m_vFrames = (entry*)malloc(iNumFrames*sizeof(entry));
		if (!m_vFrames) 
		{	mp_msg(MSGT_FIXME, MSGL_FIXME,MSGTR_OutOfMemory);
			return -2; //TC_EXPORT_ERROR;
		}
			
	   fseek(m_pFile, lFrameStart, SEEK_SET);		// start again
		
		for (i=0;i<iNumFrames;i++)
		{  fscanf(m_pFile, "Frame %d: intra %hd, quant %d, texture %d, motion %d, total %d\n",
         &dummy, &(m_vFrames[i].is_key_frame), &(m_vFrames[i].quant), 
			&(m_vFrames[i].text_bits), &(m_vFrames[i].motion_bits), 
			&(m_vFrames[i].total_bits));

			m_vFrames[i].total_bits += m_vFrames[i].text_bits*(qual_multiplier-1);
         m_vFrames[i].text_bits  *= qual_multiplier;
	 	}

	if (m_pFile)
		{	fclose(m_pFile);
			m_pFile=NULL;
		}

	desired_bits=(int64_t)bitrate*(int64_t)iNumFrames/framerate;
	non_text_bits=total_bits-text_bits;

	if(desired_bits<=non_text_bits)
	{
/*		char s[200];*/
		mp_msg(MSGT_FIXME, MSGL_FIXME, MSGTR_OverridingTooLowBitrate,
				(float)(non_text_bits*framerate/(int64_t)iNumFrames));

		desired_bits=non_text_bits*3/2;
/*
		m_fQuant=max_quantizer;
		for(int i=0; i<iNumFrames; i++)
		{
			m_vFrames[i].drop=0;
			m_vFrames[i].mult=1;
		}
		VbrControl_set_quant(m_fQuant);
		return 0;
*/
  }

	desired_bits -= non_text_bits;
		/**
		BRIEF EXPLANATION OF WHAT'S GOING ON HERE.
		We assume that 
			text_bits=complexity / quantizer
			total_bits-text_bits = const(complexity)
		where 'complexity' is a characteristic of the frame
		and does not depend much on quantizer dynamics.
		Using this equation, we calculate 'average' quantizer
		to be used for encoding ( 1st order effect ).
		Having constant quantizer for the entire stream is not
		very convenient - reconstruction errors are
		more noticeable in low-motion scenes. To compensate 
		this effect, we multiply quantizer for each frame by
			(complexity/average_complexity)^k,
		( k - parameter of adjustment ). k=0 means 'no compensation'
		and k=1 is 'constant bitrate mode'. We choose something in
		between, like 0.5 ( 2nd order effect ).
		**/
		
	average_complexity=complexity/iNumFrames;

	for(i=0; i<iNumFrames; i++)
	{
		float mult;
		if(m_vFrames[i].is_key_frame)
		{
		    if((i+1<iNumFrames) && (m_vFrames[i+1].is_key_frame))
			mult=1.25;
		    else
			mult=.75;
		}
		else
		{
			mult=m_vFrames[i].text_bits*m_vFrames[i].quant;
			mult=(float)sqrt(mult/average_complexity);
			
//			if(i && m_vFrames[i-1].is_key_frame)
//			    mult *= 0.75;
			if(mult<0.5)
			    mult=0.5;
			if(mult>1.5)
			    mult=1.5;
		}

		m_vFrames[i].mult=mult;
		m_vFrames[i].drop=FALSE;
		new_complexity+=m_vFrames[i].text_bits*m_vFrames[i].quant;

		denominator+=desired_bits*m_vFrames[i].mult/iNumFrames;
	}
	
	m_fQuant=((double)new_complexity)/(double)denominator;

	if(m_fQuant<min_quantizer) m_fQuant=min_quantizer;
	if(m_fQuant>max_quantizer) m_fQuant=max_quantizer;
	m_pFile=fopen("analyse.log", "wb");
	if(m_pFile)
	{
		fprintf(m_pFile, "Total frames: %d Avg quantizer: %f\n",
			iNumFrames, m_fQuant);
		fprintf(m_pFile, "Expecting %12lld bits\n", desired_bits+non_text_bits);
		fflush(m_pFile);
	}
	VbrControl_set_quant(m_fQuant*m_vFrames[0].mult);
	m_lEncodedBits=m_lExpectedBits=0;
	return 0;
}

int VbrControl_get_intra() 
{
	return m_vFrames[m_iCount].is_key_frame;
}

short VbrControl_get_drop() 
{
	return m_bDrop;
}

int VbrControl_get_quant() 
{
	return m_iQuant;
}

void VbrControl_set_quant(float quant)
{
	m_iQuant=quant;
	if((rand() % 10)<((quant-m_iQuant) * 10))
		m_iQuant++;
	if(m_iQuant<min_quantizer) m_iQuant=min_quantizer;
	if(m_iQuant>max_quantizer) m_iQuant=max_quantizer;
}

void VbrControl_update_1pass_vbr()
{
	VbrControl_set_quant(m_fQuant);
	m_iCount++;
}

void VbrControl_update_2pass_vbr_analysis(int is_key_frame, int motion_bits, int texture_bits, int total_bits, int quant)
{
	if(!m_pFile)
		return;
	fprintf(m_pFile, "Frame %d: intra %d, quant %d, texture %d, motion %d, total %d\n",
		m_iCount, is_key_frame, quant, texture_bits, motion_bits, total_bits);
	m_iCount++;
}

void VbrControl_update_2pass_vbr_encoding(int motion_bits, int texture_bits, int total_bits)
{
	double q;
	double dq;
		
	if(m_iCount>=iNumFrames)
		return;

	m_lExpectedBits+=(m_vFrames[m_iCount].total_bits-m_vFrames[m_iCount].text_bits)
		+ m_vFrames[m_iCount].text_bits*m_vFrames[m_iCount].quant/m_fQuant;
	m_lEncodedBits+=(int64_t)total_bits;

	if(m_pFile)
		fprintf(m_pFile, "Frame %d: PRESENT, complexity %d, quant multiplier %f, texture %d, total %d ",
				m_iCount, m_vFrames[m_iCount].text_bits*m_vFrames[m_iCount].quant,
					m_vFrames[m_iCount].mult, texture_bits, total_bits);

	m_iCount++;

	q = m_fQuant * m_vFrames[m_iCount].mult;
	if(q<m_fQuant+min_quant_delta) q=m_fQuant+min_quant_delta;
	if(q>m_fQuant+max_quant_delta) q=m_fQuant+max_quant_delta;

	dq = (double)m_lEncodedBits/(double)m_lExpectedBits;
	dq*=dq;
	if(dq<min_rc_quant_delta) 
		dq=min_rc_quant_delta;
	if(dq>max_rc_quant_delta) 
		dq=max_rc_quant_delta;
	if(m_iCount<20)					// no framerate corrections in first frames 
		dq=1;
	if(m_pFile)
		fprintf(m_pFile, "Progress: expected %12lld, achieved %12lld, dq %f",
			m_lExpectedBits, m_lEncodedBits, dq);
	q *= dq;
	VbrControl_set_quant(q);
	if(m_pFile)
		fprintf(m_pFile, ", new quant %d\n", m_iQuant);
}

void VbrControl_close()
{
	if(m_pFile)
	{
		fclose(m_pFile);
		m_pFile=NULL;
	}
	free(m_vFrames);
}