utils.c

arm平台下的H264编码和解码源代码

int avcodec_encode_audio(AVCodecContext *avctx, uint8_t *buf, int buf_size, 
                         const short *samples)
{
    int ret;

    ret = avctx->codec->encode(avctx, buf, buf_size, (void *)samples);
    avctx->frame_number++;
    return ret;
}

int avcodec_encode_video(AVCodecContext *avctx, uint8_t *buf, int buf_size, 
                         const AVFrame *pict)
{
    int ret;

    ret = avctx->codec->encode(avctx, buf, buf_size, (void *)pict);
    
    emms_c(); //needed to avoid a emms_c() call before every return;

    avctx->frame_number++;
    return ret;
}

/** 
 * decode a frame. 
 * @param buf bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE larger then the actual read bytes
 * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
 * @param buf_size the size of the buffer in bytes
 * @param got_picture_ptr zero if no frame could be decompressed, Otherwise, it is non zero
 * @return -1 if error, otherwise return the number of
 * bytes used. 
 */
int avcodec_decode_video(AVCodecContext *avctx, AVFrame *picture, 
                         int *got_picture_ptr,
                         uint8_t *buf, int buf_size)
{
    int ret;
    
    ret = avctx->codec->decode(avctx, picture, got_picture_ptr, 
                               buf, buf_size);

    emms_c(); //needed to avoid a emms_c() call before every return;
    
    if (*got_picture_ptr)                           
        avctx->frame_number++;
    return ret;
}

/* decode an audio frame. return -1 if error, otherwise return the
   *number of bytes used. If no frame could be decompressed,
   *frame_size_ptr is zero. Otherwise, it is the decompressed frame
   *size in BYTES. */
int avcodec_decode_audio(AVCodecContext *avctx, int16_t *samples, 
                         int *frame_size_ptr,
                         uint8_t *buf, int buf_size)
{
    int ret;

    ret = avctx->codec->decode(avctx, samples, frame_size_ptr, 
                               buf, buf_size);
    avctx->frame_number++;
    return ret;
}

int avcodec_close(AVCodecContext *avctx)
{
    if (avctx->codec->close)
        avctx->codec->close(avctx);
    av_freep(&avctx->priv_data);
    avctx->codec = NULL;
    return 0;
}

AVCodec *avcodec_find_encoder(enum CodecID id)
{
    AVCodec *p;
    p = first_avcodec;
    while (p) {
        if (p->encode != NULL && p->id == id)
            return p;
        p = p->next;
    }
    return NULL;
}

AVCodec *avcodec_find_encoder_by_name(const char *name)
{
    AVCodec *p;
    p = first_avcodec;
    while (p) {
        if (p->encode != NULL && strcmp(name,p->name) == 0)
            return p;
        p = p->next;
    }
    return NULL;
}

AVCodec *avcodec_find_decoder(enum CodecID id)
{
    AVCodec *p;
    p = first_avcodec;
    while (p) {
        if (p->decode != NULL && p->id == id)
            return p;
        p = p->next;
    }
    return NULL;
}

AVCodec *avcodec_find_decoder_by_name(const char *name)
{
    AVCodec *p;
    p = first_avcodec;
    while (p) {
        if (p->decode != NULL && strcmp(name,p->name) == 0)
            return p;
        p = p->next;
    }
    return NULL;
}

AVCodec *avcodec_find(enum CodecID id)
{
    AVCodec *p;
    p = first_avcodec;
    while (p) {
        if (p->id == id)
            return p;
        p = p->next;
    }
    return NULL;
}

void avcodec_string(char *buf, int buf_size, AVCodecContext *enc, int encode)
{
    const char *codec_name;
    AVCodec *p;
    char buf1[32];
    char channels_str[100];
    int bitrate;

    if (encode)
        p = avcodec_find_encoder(enc->codec_id);
    else
        p = avcodec_find_decoder(enc->codec_id);

    if (p) {
        codec_name = p->name;
        if (!encode && enc->codec_id == CODEC_ID_MP3) {
            if (enc->sub_id == 2)
                codec_name = "mp2";
            else if (enc->sub_id == 1)
                codec_name = "mp1";
        }
    } else if (enc->codec_id == CODEC_ID_MPEG2TS) {
        /* fake mpeg2 transport stream codec (currently not
           registered) */
        codec_name = "mpeg2ts";
    } else if (enc->codec_name[0] != '\0') {
        codec_name = enc->codec_name;
    } else {
        /* output avi tags */
        if (enc->codec_type == CODEC_TYPE_VIDEO) {
            snprintf(buf1, sizeof(buf1), "%c%c%c%c", 
                     enc->codec_tag & 0xff,
                     (enc->codec_tag >> 8) & 0xff,
                     (enc->codec_tag >> 16) & 0xff,
                     (enc->codec_tag >> 24) & 0xff);
        } else {
            snprintf(buf1, sizeof(buf1), "0x%04x", enc->codec_tag);
        }
        codec_name = buf1;
    }

    switch(enc->codec_type) {
    case CODEC_TYPE_VIDEO:
        snprintf(buf, buf_size,
                 "Video: %s%s",
                 codec_name, enc->mb_decision ? " (hq)" : "");
        if (enc->codec_id == CODEC_ID_RAWVIDEO) {
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", %s",
                     avcodec_get_pix_fmt_name(enc->pix_fmt));
        }
        if (enc->width) {
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", %dx%d, %0.2f fps",
                     enc->width, enc->height, 
                     (float)enc->frame_rate / enc->frame_rate_base);
        }
        if (encode) {
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", q=%d-%d", enc->qmin, enc->qmax);
        }
        bitrate = enc->bit_rate;
        break;
    case CODEC_TYPE_AUDIO:
        snprintf(buf, buf_size,
                 "Audio: %s",
                 codec_name);
        switch (enc->channels) {
            case 1:
                strcpy(channels_str, "mono");
                break;
            case 2:
                strcpy(channels_str, "stereo");
                break;
            case 6:
                strcpy(channels_str, "5:1");
                break;
            default:
                sprintf(channels_str, "%d channels", enc->channels);
                break;
        }
        if (enc->sample_rate) {
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", %d Hz, %s",
                     enc->sample_rate,
                     channels_str);
        }
        
        /* for PCM codecs, compute bitrate directly */
        switch(enc->codec_id) {
        case CODEC_ID_PCM_S16LE:
        case CODEC_ID_PCM_S16BE:
        case CODEC_ID_PCM_U16LE:
        case CODEC_ID_PCM_U16BE:
            bitrate = enc->sample_rate * enc->channels * 16;
            break;
        case CODEC_ID_PCM_S8:
        case CODEC_ID_PCM_U8:
        case CODEC_ID_PCM_ALAW:
        case CODEC_ID_PCM_MULAW:
            bitrate = enc->sample_rate * enc->channels * 8;
            break;
        default:
            bitrate = enc->bit_rate;
            break;
        }
        break;
    case CODEC_TYPE_DATA:
        snprintf(buf, buf_size, "Data: %s", codec_name);
        bitrate = enc->bit_rate;
        break;
    default:
        av_abort();
    }
    if (encode) {
        if (enc->flags & CODEC_FLAG_PASS1)
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", pass 1");
        if (enc->flags & CODEC_FLAG_PASS2)
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", pass 2");
    }
    if (bitrate != 0) {
        snprintf(buf + strlen(buf), buf_size - strlen(buf), 
                 ", %d kb/s", bitrate / 1000);
    }
}

unsigned avcodec_version( void )
{
  return LIBAVCODEC_VERSION_INT;
}

unsigned avcodec_build( void )
{
  return LIBAVCODEC_BUILD;
}

/* must be called before any other functions */
void avcodec_init(void)
{
    static int inited = 0;

    if (inited != 0)
	return;
    inited = 1;

    dsputil_static_init();
}

/**
 * Flush buffers, should be called when seeking or when swicthing to a different stream.
 */
void avcodec_flush_buffers(AVCodecContext *avctx)
{
    if(avctx->codec->flush)
        avctx->codec->flush(avctx);
}

void avcodec_default_free_buffers(AVCodecContext *s){
    int i, j;

    if(s->internal_buffer==NULL) return;
    
    for(i=0; i<INTERNAL_BUFFER_SIZE; i++){
        InternalBuffer *buf= &((InternalBuffer*)s->internal_buffer)[i];
        for(j=0; j<4; j++){
            av_freep(&buf->base[j]);
            buf->data[j]= NULL;
        }
    }
    av_freep(&s->internal_buffer);
    
    s->internal_buffer_count=0;
}

char av_get_pict_type_char(int pict_type){
    switch(pict_type){
    case I_TYPE: return 'I'; 
    case P_TYPE: return 'P'; 
    case B_TYPE: return 'B'; 
    case S_TYPE: return 'S'; 
    case SI_TYPE:return 'i'; 
    case SP_TYPE:return 'p'; 
    default:     return '?';
    }
}

int av_reduce(int *dst_nom, int *dst_den, int64_t nom, int64_t den, int64_t max){
    int exact=1, sign=0;
    int64_t gcd;

#ifndef WINCE //assert
    assert(den != 0);
#endif

    if(den < 0){
        den= -den;
        nom= -nom;
    }
    
    if(nom < 0){
        nom= -nom;
        sign= 1;
    }
    
    gcd = ff_gcd(nom, den);
    nom /= gcd;
    den /= gcd;
    
    if(nom > max || den > max){
        AVRational a0={0,1}, a1={1,0};
        exact=0;

        for(;;){
            int64_t x= nom / den;
            int64_t a2n= x*a1.num + a0.num;
            int64_t a2d= x*a1.den + a0.den;

            if(a2n > max || a2d > max) break;

            nom %= den;
        
            a0= a1;
#ifdef WINCE //AVRational
            a1.num= a2n;
			a1.den= a2d;
#else
            a1= (AVRational){a2n, a2d};
#endif
            if(nom==0) break;
            x= nom; nom=den; den=x;
        }
        nom= a1.num;
        den= a1.den;
    }

#ifndef WINCE //assert
    assert(ff_gcd(nom, den) == 1);
#endif

    if(sign) nom= -nom;
    
    *dst_nom = nom;
    *dst_den = den;
    
    return exact;
}

int64_t av_rescale(int64_t a, int b, int c){
    uint64_t h, l;
#ifndef WINCE //assert
	assert(c > 0);
    assert(b >=0);
#endif
    if(a<0) return -av_rescale(-a, b, c);
    
    h= a>>32;
    if(h==0) return a*b/c;
    
    l= a&0xFFFFFFFF;
    l *= b;
    h *= b;

    l += (h%c)<<32;

    return ((h/c)<<32) + l/c;
}

/* av_log API */

static int av_log_level = AV_LOG_DEBUG;

static void av_log_default_callback(void* ptr, int level, const char* fmt, va_list vl)
{
    static int print_prefix=1;
    AVClass* avc= ptr ? *(AVClass**)ptr : NULL;
    if(level>av_log_level)
	return;
#undef fprintf
    if(print_prefix && avc) {
	    fprintf(stderr, "[%s @ %p]", avc->item_name(ptr), avc);
    }
#define fprintf please_use_av_log
        
    print_prefix= strstr(fmt, "\n") != NULL;
        
    vfprintf(stderr, fmt, vl);
}

static void (*av_log_callback)(void*, int, const char*, va_list) = av_log_default_callback;

void av_log(void* avcl, int level, const char *fmt, ...)
{
    va_list vl;
    va_start(vl, fmt);
    av_vlog(avcl, level, fmt, vl);
    va_end(vl);
}

void av_vlog(void* avcl, int level, const char *fmt, va_list vl)
{
    av_log_callback(avcl, level, fmt, vl);
}

int av_log_get_level(void)
{
    return av_log_level;
}

void av_log_set_level(int level)
{
    av_log_level = level;
}

void av_log_set_callback(void (*callback)(void*, int, const char*, va_list))
{
    av_log_callback = callback;
}