--- plugin_2pass2.c 2004/05/09 14:00:35 1.1.2.38 +++ plugin_2pass2.c 2004/03/22 22:36:24 1.2 @@ -25,7 +25,7 @@ * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * - * $Id: plugin_2pass2.c,v 1.1.2.38 2004/05/09 14:00:35 chl Exp $ + * $Id: plugin_2pass2.c,v 1.2 2004/03/22 22:36:24 edgomez Exp $ * *****************************************************************************/ @@ -177,7 +177,7 @@ twopass_stat_t * stats; /*---------------------------------- - * Hysteresis helpers + * Histerysis helpers *--------------------------------*/ /* This field holds the int2float conversion errors of each quant per @@ -270,11 +270,6 @@ static void first_pass_stats_prepare_data(rc_2pass2_t * rc); static void first_pass_scale_curve_internal(rc_2pass2_t *rc); static void scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc); -#ifdef VBV -static int check_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps); -static int scale_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps); -#endif - #if 0 static void stats_print(rc_2pass2_t * rc); #endif @@ -431,41 +426,6 @@ * shape the curve in the BEFORE/AFTER pair of functions */ scaled_curve_apply_advanced_parameters(rc); - -#ifdef VBV -/* Check curve for VBV compliancy and rescale if necessary */ - - -#ifdef VBV_FORCE - if (rc->param.vbvsize==0) - { - rc->param.vbvsize = 3145728; - rc->param.vbvinitial = 2359296; - rc->param.vbv_maxrate = 4000000; - rc->param.vbv_peakrate = 10000000; - } -#endif - - if (rc->param.vbvsize>0) /* vbvsize==0 switches VBV check off */ - { - const double fps = (double)create->fbase/(double)create->fincr; - int status = check_curve_for_vbv_compliancy(rc, fps); -#ifdef VBV_DEBUG - if (status) - fprintf(stderr,"underflow detected\n Scaling Curve for compliancy... "); -#endif - - status = scale_curve_for_vbv_compliancy(rc, fps); - -#ifdef VBV_DEBUG - if (status==0) - fprintf(stderr,"done.\n"); - else - fprintf(stderr,"impossible.\n"); -#endif - } -#endif - *handle = rc; return(0); } @@ -1420,307 +1380,6 @@ return; } - -#ifdef VBV - -/***************************************************************************** - * VBV compliancy check and scale - * MPEG-4 standard specifies certain restrictions for bitrate/framesize in VBR - * to enable playback on devices with limited readspeed and memory (and which - * aren't...) - * - * DivX profiles have 2 criteria: VBV as in MPEG standard - * a limit on peak bitrate for any 3 seconds - * - * But if VBV is fulfilled, peakrate is automatically fulfilled in any profile - * define so far, so we check for it (for completeness) but correct only VBV - * - *****************************************************************************/ - -#define VBV_COMPLIANT 0 -#define VBV_UNDERFLOW 1 /* video buffer runs empty */ -#define VBV_OVERFLOW 2 /* doesn't exist for VBR encoding */ -#define VBV_PEAKRATE 4 /* peak bitrate (within 3s) violated */ - -static int check_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps) -{ -/* We do all calculations in float, for higher accuracy, and bytes for convenience - - typical values from DivX Home Theater profile: - vbvsize= 384*1024 (384kB), vbvinitial= 288*1024 (75% fill) - maxrate= 4000000 (4MBps), peakrate= 10000000 (10MBps) - - PAL: offset3s = 75 (3 seconds of 25fps) - NTSC: offset3s = 90 (3 seconds of 29.97fps) or 72 (3 seconds of 23.976fps) -*/ - - const float vbvsize = (float)rc->param.vbvsize/8.f; - float vbvfill = (float)rc->param.vbvinitial/8.f; - - const float maxrate = (float)rc->param.vbv_maxrate; - const float peakrate = (float)rc->param.vbv_peakrate; - const float r0 = (int)(maxrate/fps+0.5)/8.f; - - int bytes3s = 0; - int offset3s = (int)(3.f*fps+0.5); - - int i; - for (i=0; inum_frames; i++) { -/* DivX 3s peak bitrate check */ - - bytes3s += rc->stats[i].scaled_length; - if (i>=offset3s) - bytes3s -= rc->stats[i-offset3s].scaled_length; - - if (8.f*bytes3s > 3*peakrate) - return VBV_PEAKRATE; - -/* update vbv fill level */ - - vbvfill += r0 - rc->stats[i].scaled_length; - -/* this check is _NOT_ an "overflow"! only reading from disk stops then */ - if (vbvfill > vbvsize) - vbvfill = vbvsize; - -/* but THIS would be an underflow. report it! */ - if (vbvfill < 0) - return VBV_UNDERFLOW; - } - - return VBV_COMPLIANT; -} -/* idea: min(vbvfill) could be stored to print "minimum buffer fill" */ - - - -static int scale_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps) -{ -/* correct any VBV violations. Peak bitrate violations disappears - by this automatically - - This implementation follows - - Westerink, Rajagopalan, Gonzales "Two-pass MPEG-2 variable-bitrate encoding" - IBM J. RES. DEVELOP. VOL 43, No. 4, July 1999, p.471--488 - - Thanks, guys! This paper rocks!!! -*/ - -/* - For each scene of len N, we have to check up to N^2 possible buffer fills. - This works well with MPEG-2 where N==12 or so, but for MPEG-4 it's a - little slow... -*/ - const float vbvsize = (float)rc->param.vbvsize/8.f; - const float vbvinitial = (float)rc->param.vbvinitial/8.f; - - const float maxrate = 0.9*rc->param.vbv_maxrate; - const float vbvlow = 0.10f*vbvsize; - const float r0 = (int)(maxrate/fps+0.5)/8.f; - - int i,k,l,n,violation = 0; - float *scenefactor; - int *scenestart; - int *scenelength; - -/* first step: determine how many "scenes" there are and store their boundaries - we could get all this from existing keyframe_positions, somehow, but there we - don't have a min_scenelength, and it's no big deal to get it again. */ - - const int min_scenelength = 50; - int num_scenes = 0; - int last_scene = -999; - for (i=0; inum_frames; i++) { - if ( (rc->stats[i].type == XVID_TYPE_IVOP) && (i-last_scene>min_scenelength) ) - { - last_scene = i; - num_scenes++; - } - } - - scenefactor = (float*)malloc( num_scenes*sizeof(float) ); - scenestart = (int*)malloc( num_scenes*sizeof(int) ); - scenelength = (int*)malloc( num_scenes*sizeof(int) ); - - if ((!scenefactor) || (!scenestart) || (!scenelength) ) - { - free(scenefactor); - free(scenestart); - free(scenelength); - /* remember: free(0) is valid and does exactly nothing. */ - return -1; - } - -/* count again and safe the length/position */ - - num_scenes = 0; - last_scene = -999; - for (i=0; inum_frames; i++) { - if ( (rc->stats[i].type == XVID_TYPE_IVOP) && (i-last_scene>min_scenelength) ) - { - if (num_scenes>0) - scenelength[num_scenes-1]=i-last_scene; - scenestart[num_scenes]=i; - num_scenes++; - last_scene = i; - } - } - scenelength[num_scenes-1]=i-last_scene; - -/* second step: check for each scene, how much we can scale its frames up or down - such that the VBV restriction is just fulfilled -*/ - - -#define R(k,n) (((n)+1-(k))*r0) /* how much enters the buffer between frame k and n */ - for (l=0; lstats[start]; - - float S0n,Skn; - float f,minf = 99999.f; - - S0n=0.; - for (n=0;n<=length-1;n++) - { - S0n += frames[n].scaled_length; - - k=0; - Skn = S0n; - f = (R(k,n-1) + (vbvinitial - vbvlow)) / Skn; - if (f < minf) - minf = f; - - for (k=1;k<=n;k++) - { - Skn -= frames[k].scaled_length; - - f = (R(k,n-1) + (vbvsize - vbvlow)) / Skn; - if (f < minf) - minf = f; - } - } - - /* special case: at the end, fill buffer up to vbvinitial again - TODO: Allow other values for buffer fill between scenes - e.g. if n=N is smallest f-value, then check for better value */ - - n=length; - k=0; - Skn = S0n; - f = R(k,n-1)/Skn; - if (f < minf) - minf = f; - - for (k=1;k<=n-1;k++) - { - Skn -= frames[k].scaled_length; - - f = (R(k,n-1) + (vbvinitial - vbvlow)) / Skn; - if (f < minf) - minf = f; - } - -#ifdef VBV_DEBUG - printf("Scene %d (Frames %d-%d): VBVfactor %f\n", l, start, start+length-1 , minf); -#endif - - scenefactor[l] = minf; - } -#undef R - -/* last step: now we know of any scene how much it can be scaled up or down without - violating VBV. Next, distribute bits from the evil scenes to the good ones */ - - do - { - float S_red = 0.f; /* how much to redistribute */ - float S_elig = 0.f; /* sum of bit for those scenes you can still swallow something*/ - int l; - - for (l=0;lstats[start]; - - if (scenefactor[l] == 1.) /* exactly 1 means "don't touch this anymore!" */ - continue; - - if (scenefactor[l] > 1.) /* within limits */ - { - for (n= 0; n < length; n++) - S_elig += frames[n].scaled_length; - } - else /* underflowing segment */ - { - for (n= 0; n < length; n++) - { - float newbytes = (float)frames[n].scaled_length * scenefactor[l]; - S_red += (float)frames[n].scaled_length - (float)newbytes; - frames[n].scaled_length =(int)newbytes; - } - scenefactor[l] = 1.f; - } - } - - if (S_red < 1.f) /* no more underflows */ - break; - - if (S_elig < 1.f) - { -#ifdef VBV_DEBUG - fprintf(stderr,"Everything underflowing. \n"); -#endif - free(scenefactor); - free(scenestart); - free(scenelength); - return -2; - } - - const float f_red = (1.f + S_red/S_elig); - -#ifdef VBV_DEBUG - printf("Moving %.0f kB to avoid buffer underflow, correction factor: %.5f\n",S_red/1024.f,f_red); -#endif - - violation=0; - for (l=0; lstats[start]; - - if (scenefactor[l] == 1.) - continue; - - /* there shouldn't be any segments with factor<1 left, so all the rest is >1 */ - - for (n= 0; n < length; n++) - { - frames[n].scaled_length = (int)(frames[n].scaled_length * f_red + 0.5); - } - - scenefactor[l] /= f_red; - if (scenefactor[l] < 1.f) - violation=1; - } - - } while (violation); - - free(scenefactor); - free(scenestart); - free(scenelength); - return 0; -} - - -#endif - - /***************************************************************************** * Still more low level stuff (nothing to do with stats treatment) ****************************************************************************/