utils.c

ffmpeg源码分析

{"mb_threshold", NULL, OFFSET(mb_threshold), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX},
{"dc", NULL, OFFSET(intra_dc_precision), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"nssew", "nsse weight", OFFSET(nsse_weight), FF_OPT_TYPE_INT, 8, INT_MIN, INT_MAX, V|E},
{"skip_top", NULL, OFFSET(skip_top), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|D},
{"skip_bottom", NULL, OFFSET(skip_bottom), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|D},
{"profile", NULL, OFFSET(profile), FF_OPT_TYPE_INT, FF_PROFILE_UNKNOWN, INT_MIN, INT_MAX, V|A|E, "profile"},
{"unknown", NULL, 0, FF_OPT_TYPE_CONST, FF_PROFILE_UNKNOWN, INT_MIN, INT_MAX, V|A|E, "profile"},
{"level", NULL, OFFSET(level), FF_OPT_TYPE_INT, FF_LEVEL_UNKNOWN, INT_MIN, INT_MAX, V|A|E, "level"},
{"unknown", NULL, 0, FF_OPT_TYPE_CONST, FF_LEVEL_UNKNOWN, INT_MIN, INT_MAX, V|A|E, "level"},
{"lowres", NULL, OFFSET(lowres), FF_OPT_TYPE_INT, 0, 0, INT_MAX, V|D},
{"frame_skip_threshold", NULL, OFFSET(frame_skip_threshold), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"frame_skip_factor", NULL, OFFSET(frame_skip_factor), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"frame_skip_exp", NULL, OFFSET(frame_skip_exp), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"skipcmp", "frame skip compare function", OFFSET(frame_skip_cmp), FF_OPT_TYPE_INT, FF_CMP_DCTMAX, INT_MIN, INT_MAX, V|E, "cmp_func"},
{"border_mask", NULL, OFFSET(border_masking), FF_OPT_TYPE_FLOAT, DEFAULT, FLT_MIN, FLT_MAX, V|E},
{"mb_lmin", NULL, OFFSET(mb_lmin), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"mb_lmax", NULL, OFFSET(mb_lmax), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"me_penalty_compensation", NULL, OFFSET(me_penalty_compensation), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"bidir_refine", NULL, OFFSET(bidir_refine), FF_OPT_TYPE_INT, DEFAULT, 0, 4, V|E},
{"brd_scale", NULL, OFFSET(brd_scale), FF_OPT_TYPE_INT, DEFAULT, 0, 10, V|E},
{"crf", NULL, OFFSET(crf), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"cqp", NULL, OFFSET(cqp), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"keyint_min", NULL, OFFSET(keyint_min), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"refs", NULL, OFFSET(refs), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"chromaoffset", NULL, OFFSET(chromaoffset), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"bframebias", NULL, OFFSET(bframebias), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"trellis", NULL, OFFSET(trellis), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"directpred", NULL, OFFSET(directpred), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"bpyramid", NULL, 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_BPYRAMID, INT_MIN, INT_MAX, V|E, "flags2"},
{"wpred", NULL, 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_WPRED, INT_MIN, INT_MAX, V|E, "flags2"},
{"mixed_refs", NULL, 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_MIXED_REFS, INT_MIN, INT_MAX, V|E, "flags2"},
{"8x8dct", NULL, 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_8X8DCT, INT_MIN, INT_MAX, V|E, "flags2"},
{"fastpskip", NULL, 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_FASTPSKIP, INT_MIN, INT_MAX, V|E, "flags2"},
{"aud", NULL, 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_AUD, INT_MIN, INT_MAX, V|E, "flags2"},
{"brdo", NULL, 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_BRDO, INT_MIN, INT_MAX, V|E, "flags2"},
{"complexityblur", NULL, OFFSET(complexityblur), FF_OPT_TYPE_FLOAT, DEFAULT, FLT_MIN, FLT_MAX, V|E},
{"deblockalpha", NULL, OFFSET(deblockalpha), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"deblockbeta", NULL, OFFSET(deblockbeta), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"partitions", NULL, OFFSET(partitions), FF_OPT_TYPE_FLAGS, DEFAULT, INT_MIN, INT_MAX, V|E, "partitions"},
{"parti4x4", NULL, 0, FF_OPT_TYPE_CONST, X264_PART_I4X4, INT_MIN, INT_MAX, V|E, "partitions"},
{"parti8x8", NULL, 0, FF_OPT_TYPE_CONST, X264_PART_I8X8, INT_MIN, INT_MAX, V|E, "partitions"},
{"partp4x4", NULL, 0, FF_OPT_TYPE_CONST, X264_PART_P4X4, INT_MIN, INT_MAX, V|E, "partitions"},
{"partp8x8", NULL, 0, FF_OPT_TYPE_CONST, X264_PART_P8X8, INT_MIN, INT_MAX, V|E, "partitions"},
{"partb8x8", NULL, 0, FF_OPT_TYPE_CONST, X264_PART_B8X8, INT_MIN, INT_MAX, V|E, "partitions"},
{"sc_factor", NULL, OFFSET(scenechange_factor), FF_OPT_TYPE_INT, 6, 0, INT_MAX, V|E},
{NULL},
};

#undef A
#undef V

static AVClass av_codec_context_class = { "AVCodecContext", context_to_name, options };

void avcodec_get_context_defaults(AVCodecContext *s){
    memset(s, 0, sizeof(AVCodecContext));

    s->av_class= &av_codec_context_class;
    s->bit_rate= 800*1000;
    s->bit_rate_tolerance= s->bit_rate*10;
    s->qmin= 2;
    s->qmax= 31;
    s->mb_lmin= FF_QP2LAMBDA * 2;
    s->mb_lmax= FF_QP2LAMBDA * 31;
    s->rc_eq= "tex^qComp";
    s->cqp = -1;
    s->refs = 1;
    s->directpred = 2;
    s->qcompress= 0.5;
    s->complexityblur = 20.0;
    s->keyint_min = 25;
    s->flags2 = CODEC_FLAG2_FASTPSKIP;
    s->max_qdiff= 3;
    s->b_quant_factor=1.25;
    s->b_quant_offset=1.25;
    s->i_quant_factor=-0.8;
    s->i_quant_offset=0.0;
    s->error_concealment= 3;
    s->error_resilience= 1;
    s->workaround_bugs= FF_BUG_AUTODETECT;
    s->time_base= (AVRational){0,1};
    s->gop_size= 50;
    s->me_method= ME_EPZS;
    s->get_buffer= avcodec_default_get_buffer;
    s->release_buffer= avcodec_default_release_buffer;
    s->get_format= avcodec_default_get_format;
    s->execute= avcodec_default_execute;
    s->thread_count=1;
    s->me_subpel_quality=8;
    s->lmin= FF_QP2LAMBDA * s->qmin;
    s->lmax= FF_QP2LAMBDA * s->qmax;
    s->sample_aspect_ratio= (AVRational){0,1};
    s->ildct_cmp= FF_CMP_VSAD;
    s->profile= FF_PROFILE_UNKNOWN;
    s->level= FF_LEVEL_UNKNOWN;
    s->me_penalty_compensation= 256;
    s->pix_fmt= PIX_FMT_NONE;
    s->frame_skip_cmp= FF_CMP_DCTMAX;
    s->nsse_weight= 8;
    s->sample_fmt= SAMPLE_FMT_S16; // FIXME: set to NONE

    s->intra_quant_bias= FF_DEFAULT_QUANT_BIAS;
    s->inter_quant_bias= FF_DEFAULT_QUANT_BIAS;
    s->palctrl = NULL;
    s->reget_buffer= avcodec_default_reget_buffer;
}

/**
 * allocates a AVCodecContext and set it to defaults.
 * this can be deallocated by simply calling free()
 */
AVCodecContext *avcodec_alloc_context(void){
    AVCodecContext *avctx= av_malloc(sizeof(AVCodecContext));

    if(avctx==NULL) return NULL;

    avcodec_get_context_defaults(avctx);

    return avctx;
}

void avcodec_get_frame_defaults(AVFrame *pic){
    memset(pic, 0, sizeof(AVFrame));

    pic->pts= AV_NOPTS_VALUE;
    pic->key_frame= 1;
}

/**
 * allocates a AVPFrame and set it to defaults.
 * this can be deallocated by simply calling free()
 */
AVFrame *avcodec_alloc_frame(void){
    AVFrame *pic= av_malloc(sizeof(AVFrame));

    if(pic==NULL) return NULL;

    avcodec_get_frame_defaults(pic);

    return pic;
}

int avcodec_open(AVCodecContext *avctx, AVCodec *codec)
{
    int ret= -1;

    entangled_thread_counter++;
    if(entangled_thread_counter != 1){
        av_log(avctx, AV_LOG_ERROR, "insufficient thread locking around avcodec_open/close()\n");
        goto end;
    }

    if(avctx->codec)
        goto end;

    if (codec->priv_data_size > 0) {
        avctx->priv_data = av_mallocz(codec->priv_data_size);
        if (!avctx->priv_data)
            goto end;
    } else {
        avctx->priv_data = NULL;
    }

    if(avctx->coded_width && avctx->coded_height)
        avcodec_set_dimensions(avctx, avctx->coded_width, avctx->coded_height);
    else if(avctx->width && avctx->height)
        avcodec_set_dimensions(avctx, avctx->width, avctx->height);

    if((avctx->coded_width||avctx->coded_height) && avcodec_check_dimensions(avctx,avctx->coded_width,avctx->coded_height)){
        av_freep(&avctx->priv_data);
        goto end;
    }

    avctx->codec = codec;
    avctx->codec_id = codec->id;
    avctx->frame_number = 0;
    ret = avctx->codec->init(avctx);
    if (ret < 0) {
        av_freep(&avctx->priv_data);
        avctx->codec= NULL;
        goto end;
    }
    ret=0;
end:
    entangled_thread_counter--;
    return ret;
}

int avcodec_encode_audio(AVCodecContext *avctx, uint8_t *buf, int buf_size,
                         const short *samples)
{
    if(buf_size < FF_MIN_BUFFER_SIZE && 0){
        av_log(avctx, AV_LOG_ERROR, "buffer smaller then minimum size\n");
        return -1;
    }
    if((avctx->codec->capabilities & CODEC_CAP_DELAY) || samples){
        int ret = avctx->codec->encode(avctx, buf, buf_size, (void *)samples);
        avctx->frame_number++;
        return ret;
    }else
        return 0;
}

int avcodec_encode_video(AVCodecContext *avctx, uint8_t *buf, int buf_size,
                         const AVFrame *pict)
{
    if(buf_size < FF_MIN_BUFFER_SIZE){
        av_log(avctx, AV_LOG_ERROR, "buffer smaller then minimum size\n");
        return -1;
    }
    if(avcodec_check_dimensions(avctx,avctx->width,avctx->height))
        return -1;
    if((avctx->codec->capabilities & CODEC_CAP_DELAY) || pict){
        int ret = avctx->codec->encode(avctx, buf, buf_size, (void *)pict);
        avctx->frame_number++;
        emms_c(); //needed to avoid an emms_c() call before every return;

        return ret;
    }else
        return 0;
}

int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
                            const AVSubtitle *sub)
{
    int ret;
    ret = avctx->codec->encode(avctx, buf, buf_size, (void *)sub);
    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;

    *got_picture_ptr= 0;
    if((avctx->coded_width||avctx->coded_height) && avcodec_check_dimensions(avctx,avctx->coded_width,avctx->coded_height))
        return -1;
    if((avctx->codec->capabilities & CODEC_CAP_DELAY) || buf_size){
        ret = avctx->codec->decode(avctx, picture, got_picture_ptr,
                                buf, buf_size);

        emms_c(); //needed to avoid an emms_c() call before every return;

        if (*got_picture_ptr)
            avctx->frame_number++;
    }else
        ret= 0;

    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;

    *frame_size_ptr= 0;
    if((avctx->codec->capabilities & CODEC_CAP_DELAY) || buf_size){
        ret = avctx->codec->decode(avctx, samples, frame_size_ptr,
                                buf, buf_size);
        avctx->frame_number++;
    }else
        ret= 0;
    return ret;
}

/* decode a subtitle message. return -1 if error, otherwise return the
   *number of bytes used. If no subtitle could be decompressed,
   *got_sub_ptr is zero. Otherwise, the subtitle is stored in *sub. */
int avcodec_decode_subtitle(AVCodecContext *avctx, AVSubtitle *sub,
                            int *got_sub_ptr,
                            const uint8_t *buf, int buf_size)
{
    int ret;

    *got_sub_ptr = 0;
    ret = avctx->codec->decode(avctx, sub, got_sub_ptr,
                               (uint8_t *)buf, buf_size);
    if (*got_sub_ptr)
        avctx->frame_number++;
    return ret;
}

int avcodec_close(AVCodecContext *avctx)
{
    entangled_thread_counter++;
    if(entangled_thread_counter != 1){
        av_log(avctx, AV_LOG_ERROR, "insufficient thread locking around avcodec_open/close()\n");
        entangled_thread_counter--;
        return -1;
    }

    if (avctx->codec->close)
        avctx->codec->close(avctx);
    avcodec_default_free_buffers(avctx);
    av_freep(&avctx->priv_data);
    avctx->codec = NULL;
    entangled_thread_counter--;
    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;