utils.c

ffmpeg源码分析

/*
 * utils for libavcodec
 * Copyright (c) 2001 Fabrice Bellard.
 * Copyright (c) 2003 Michel Bardiaux for the av_log API
 * Copyright (c) 2002-2004 Michael Niedermayer <[e-mail]>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file utils.c
 * utils.
 */

#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"
#include "integer.h"
#include "opt.h"
#include "crc.h"
#include <stdarg.h>
#include <limits.h>
#include <float.h>
#ifdef CONFIG_WIN32
#include <fcntl.h>
#endif

const uint8_t ff_reverse[256]={
0x00,0x80,0x40,0xC0,0x20,0xA0,0x60,0xE0,0x10,0x90,0x50,0xD0,0x30,0xB0,0x70,0xF0,
0x08,0x88,0x48,0xC8,0x28,0xA8,0x68,0xE8,0x18,0x98,0x58,0xD8,0x38,0xB8,0x78,0xF8,
0x04,0x84,0x44,0xC4,0x24,0xA4,0x64,0xE4,0x14,0x94,0x54,0xD4,0x34,0xB4,0x74,0xF4,
0x0C,0x8C,0x4C,0xCC,0x2C,0xAC,0x6C,0xEC,0x1C,0x9C,0x5C,0xDC,0x3C,0xBC,0x7C,0xFC,
0x02,0x82,0x42,0xC2,0x22,0xA2,0x62,0xE2,0x12,0x92,0x52,0xD2,0x32,0xB2,0x72,0xF2,
0x0A,0x8A,0x4A,0xCA,0x2A,0xAA,0x6A,0xEA,0x1A,0x9A,0x5A,0xDA,0x3A,0xBA,0x7A,0xFA,
0x06,0x86,0x46,0xC6,0x26,0xA6,0x66,0xE6,0x16,0x96,0x56,0xD6,0x36,0xB6,0x76,0xF6,
0x0E,0x8E,0x4E,0xCE,0x2E,0xAE,0x6E,0xEE,0x1E,0x9E,0x5E,0xDE,0x3E,0xBE,0x7E,0xFE,
0x01,0x81,0x41,0xC1,0x21,0xA1,0x61,0xE1,0x11,0x91,0x51,0xD1,0x31,0xB1,0x71,0xF1,
0x09,0x89,0x49,0xC9,0x29,0xA9,0x69,0xE9,0x19,0x99,0x59,0xD9,0x39,0xB9,0x79,0xF9,
0x05,0x85,0x45,0xC5,0x25,0xA5,0x65,0xE5,0x15,0x95,0x55,0xD5,0x35,0xB5,0x75,0xF5,
0x0D,0x8D,0x4D,0xCD,0x2D,0xAD,0x6D,0xED,0x1D,0x9D,0x5D,0xDD,0x3D,0xBD,0x7D,0xFD,
0x03,0x83,0x43,0xC3,0x23,0xA3,0x63,0xE3,0x13,0x93,0x53,0xD3,0x33,0xB3,0x73,0xF3,
0x0B,0x8B,0x4B,0xCB,0x2B,0xAB,0x6B,0xEB,0x1B,0x9B,0x5B,0xDB,0x3B,0xBB,0x7B,0xFB,
0x07,0x87,0x47,0xC7,0x27,0xA7,0x67,0xE7,0x17,0x97,0x57,0xD7,0x37,0xB7,0x77,0xF7,
0x0F,0x8F,0x4F,0xCF,0x2F,0xAF,0x6F,0xEF,0x1F,0x9F,0x5F,0xDF,0x3F,0xBF,0x7F,0xFF,
};

static int volatile entangled_thread_counter=0;

void avcodec_default_free_buffers(AVCodecContext *s);

void *av_mallocz(unsigned int size)
{
    void *ptr;

    ptr = av_malloc(size);
    if (!ptr)
        return NULL;
    memset(ptr, 0, size);
    return ptr;
}

char *av_strdup(const char *s)
{
    char *ptr;
    int len;
    len = strlen(s) + 1;
    ptr = av_malloc(len);
    if (!ptr)
        return NULL;
    memcpy(ptr, s, len);
    return ptr;
}

/**
 * realloc which does nothing if the block is large enough
 */
void *av_fast_realloc(void *ptr, unsigned int *size, unsigned int min_size)
{
    if(min_size < *size)
        return ptr;

    *size= FFMAX(17*min_size/16 + 32, min_size);

    return av_realloc(ptr, *size);
}


static unsigned int last_static = 0;
static unsigned int allocated_static = 0;
static void** array_static = NULL;

/**
 * allocation of static arrays - do not use for normal allocation.
 */
void *av_mallocz_static(unsigned int size)
{
    void *ptr = av_mallocz(size);

    if(ptr){
        array_static =av_fast_realloc(array_static, &allocated_static, sizeof(void*)*(last_static+1));
        if(!array_static)
            return NULL;
        array_static[last_static++] = ptr;
    }

    return ptr;
}

/**
 * same as above, but does realloc
 */

void *av_realloc_static(void *ptr, unsigned int size)
{
    int i;
    if(!ptr)
      return av_mallocz_static(size);
    /* Look for the old ptr */
    for(i = 0; i < last_static; i++) {
        if(array_static[i] == ptr) {
            array_static[i] = av_realloc(array_static[i], size);
            return array_static[i];
        }
    }
    return NULL;

}

/**
 * free all static arrays and reset pointers to 0.
 */
void av_free_static(void)
{
    while(last_static){
        av_freep(&array_static[--last_static]);
    }
    av_freep(&array_static);
}

/**
 * Call av_free_static automatically before it's too late
 */

static void do_free(void) __attribute__ ((destructor));

static void do_free(void)
{
    av_free_static();
}

/**
 * Frees memory and sets the pointer to NULL.
 * @param arg pointer to the pointer which should be freed
 */
void av_freep(void *arg)
{
    void **ptr= (void**)arg;
    av_free(*ptr);
    *ptr = NULL;
}

/* encoder management */
AVCodec *first_avcodec = NULL;

void register_avcodec(AVCodec *format)
{
    AVCodec **p;
    p = &first_avcodec;
    while (*p != NULL) p = &(*p)->next;
    *p = format;
    format->next = NULL;
}

void avcodec_set_dimensions(AVCodecContext *s, int width, int height){
    s->coded_width = width;
    s->coded_height= height;
    s->width = -((-width )>>s->lowres);
    s->height= -((-height)>>s->lowres);
}

typedef struct InternalBuffer{
    int last_pic_num;
    uint8_t *base[4];
    uint8_t *data[4];
    int linesize[4];
}InternalBuffer;

#define INTERNAL_BUFFER_SIZE 32

#define ALIGN(x, a) (((x)+(a)-1)&~((a)-1))

void avcodec_align_dimensions(AVCodecContext *s, int *width, int *height){
    int w_align= 1;
    int h_align= 1;

    switch(s->pix_fmt){
    case PIX_FMT_YUV420P:
    case PIX_FMT_YUV422:
    case PIX_FMT_UYVY422:
    case PIX_FMT_YUV422P:
    case PIX_FMT_YUV444P:
    case PIX_FMT_GRAY8:
    case PIX_FMT_YUVJ420P:
    case PIX_FMT_YUVJ422P:
    case PIX_FMT_YUVJ444P:
        w_align= 16; //FIXME check for non mpeg style codecs and use less alignment
        h_align= 16;
        break;
    case PIX_FMT_YUV411P:
    case PIX_FMT_UYVY411:
        w_align=32;
        h_align=8;
        break;
    case PIX_FMT_YUV410P:
        if(s->codec_id == CODEC_ID_SVQ1){
            w_align=64;
            h_align=64;
        }
    case PIX_FMT_RGB555:
        if(s->codec_id == CODEC_ID_RPZA){
            w_align=4;
            h_align=4;
        }
    case PIX_FMT_PAL8:
        if(s->codec_id == CODEC_ID_SMC){
            w_align=4;
            h_align=4;
        }
        break;
    case PIX_FMT_BGR24:
        if((s->codec_id == CODEC_ID_MSZH) || (s->codec_id == CODEC_ID_ZLIB)){
            w_align=4;
            h_align=4;
        }
        break;
    default:
        w_align= 1;
        h_align= 1;
        break;
    }

    *width = ALIGN(*width , w_align);
    *height= ALIGN(*height, h_align);
}

int avcodec_check_dimensions(void *av_log_ctx, unsigned int w, unsigned int h){
    if((int)w>0 && (int)h>0 && (w+128)*(uint64_t)(h+128) < INT_MAX/4)
        return 0;

    av_log(av_log_ctx, AV_LOG_ERROR, "picture size invalid (%ux%u)\n", w, h);
    return -1;
}

int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic){
    int i;
    int w= s->width;
    int h= s->height;
    InternalBuffer *buf;
    int *picture_number;

    assert(pic->data[0]==NULL);
    assert(INTERNAL_BUFFER_SIZE > s->internal_buffer_count);

    if(avcodec_check_dimensions(s,w,h))
        return -1;

    if(s->internal_buffer==NULL){
        s->internal_buffer= av_mallocz(INTERNAL_BUFFER_SIZE*sizeof(InternalBuffer));
    }
#if 0
    s->internal_buffer= av_fast_realloc(
        s->internal_buffer,
        &s->internal_buffer_size,
        sizeof(InternalBuffer)*FFMAX(99,  s->internal_buffer_count+1)/*FIXME*/
        );
#endif

    buf= &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
    picture_number= &(((InternalBuffer*)s->internal_buffer)[INTERNAL_BUFFER_SIZE-1]).last_pic_num; //FIXME ugly hack
    (*picture_number)++;

    if(buf->base[0]){
        pic->age= *picture_number - buf->last_pic_num;
        buf->last_pic_num= *picture_number;
    }else{
        int h_chroma_shift, v_chroma_shift;
        int pixel_size, size[3];
        AVPicture picture;

        avcodec_get_chroma_sub_sample(s->pix_fmt, &h_chroma_shift, &v_chroma_shift);

        avcodec_align_dimensions(s, &w, &h);

        if(!(s->flags&CODEC_FLAG_EMU_EDGE)){
            w+= EDGE_WIDTH*2;
            h+= EDGE_WIDTH*2;
        }
        avpicture_fill(&picture, NULL, s->pix_fmt, w, h);
        pixel_size= picture.linesize[0]*8 / w;
//av_log(NULL, AV_LOG_ERROR, "%d %d %d %d\n", (int)picture.data[1], w, h, s->pix_fmt);
        assert(pixel_size>=1);
            //FIXME next ensures that linesize= 2^x uvlinesize, thats needed because some MC code assumes it
        if(pixel_size == 3*8)
            w= ALIGN(w, STRIDE_ALIGN<<h_chroma_shift);
        else
            w= ALIGN(pixel_size*w, STRIDE_ALIGN<<(h_chroma_shift+3)) / pixel_size;
        size[1] = avpicture_fill(&picture, NULL, s->pix_fmt, w, h);
        size[0] = picture.linesize[0] * h;
        size[1] -= size[0];
        if(picture.data[2])
            size[1]= size[2]= size[1]/2;
        else
            size[2]= 0;

        buf->last_pic_num= -256*256*256*64;
        memset(buf->base, 0, sizeof(buf->base));
        memset(buf->data, 0, sizeof(buf->data));

        for(i=0; i<3 && size[i]; i++){
            const int h_shift= i==0 ? 0 : h_chroma_shift;
            const int v_shift= i==0 ? 0 : v_chroma_shift;

            buf->linesize[i]= picture.linesize[i];

            buf->base[i]= av_malloc(size[i]+16); //FIXME 16
            if(buf->base[i]==NULL) return -1;
            memset(buf->base[i], 128, size[i]);

            // no edge if EDEG EMU or not planar YUV, we check for PAL8 redundantly to protect against a exploitable bug regression ...
            if((s->flags&CODEC_FLAG_EMU_EDGE) || (s->pix_fmt == PIX_FMT_PAL8) || !size[2])
                buf->data[i] = buf->base[i];
            else
                buf->data[i] = buf->base[i] + ALIGN((buf->linesize[i]*EDGE_WIDTH>>v_shift) + (EDGE_WIDTH>>h_shift), STRIDE_ALIGN);
        }
        pic->age= 256*256*256*64;
    }