utils.c

ffmpeg移植到symbian的全部源代码

        }
    }

    /* we read the first packets to get the first PTS (not fully
       accurate, but it is enough now) */
    url_fseek(ic->pb, 0, SEEK_SET);
    read_size = 0;
    for(;;) {
        if (read_size >= DURATION_MAX_READ_SIZE)
            break;
        /* if all info is available, we can stop */
        for(i = 0;i < ic->nb_streams; i++) {
            st = ic->streams[i];
            if (st->start_time == AV_NOPTS_VALUE)
                break;
        }
        if (i == ic->nb_streams)
            break;

        ret = av_read_packet(ic, pkt);
        if (ret != 0)
            break;
        read_size += pkt->size;
        st = ic->streams[pkt->stream_index];
        if (pkt->pts != AV_NOPTS_VALUE) {
            if (st->start_time == AV_NOPTS_VALUE)
                st->start_time = pkt->pts;
        }
        av_free_packet(pkt);
    }

    /* estimate the end time (duration) */
    /* XXX: may need to support wrapping */
    filesize = ic->file_size;
    offset = filesize - DURATION_MAX_READ_SIZE;
    if (offset < 0)
        offset = 0;

    url_fseek(ic->pb, offset, SEEK_SET);
    read_size = 0;
    for(;;) {
        if (read_size >= DURATION_MAX_READ_SIZE)
            break;

        ret = av_read_packet(ic, pkt);
        if (ret != 0)
            break;
        read_size += pkt->size;
        st = ic->streams[pkt->stream_index];
        if (pkt->pts != AV_NOPTS_VALUE &&
            st->start_time != AV_NOPTS_VALUE) {
            end_time = pkt->pts;
            duration = end_time - st->start_time;
            if (duration > 0) {
                if (st->duration == AV_NOPTS_VALUE ||
                    st->duration < duration)
                    st->duration = duration;
            }
        }
        av_free_packet(pkt);
    }

    fill_all_stream_timings(ic);

    url_fseek(ic->pb, old_offset, SEEK_SET);
    for(i=0; i<ic->nb_streams; i++){
        st= ic->streams[i];
        st->cur_dts= st->first_dts;
        st->last_IP_pts = AV_NOPTS_VALUE;
    }
}

static void av_estimate_timings(AVFormatContext *ic, offset_t old_offset)
{
    int64_t file_size;

    /* get the file size, if possible */
    if (ic->iformat->flags & AVFMT_NOFILE) {
        file_size = 0;
    } else {
        file_size = url_fsize(ic->pb);
        if (file_size < 0)
            file_size = 0;
    }
    ic->file_size = file_size;

    if ((!strcmp(ic->iformat->name, "mpeg") ||
         !strcmp(ic->iformat->name, "mpegts")) &&
        file_size && !url_is_streamed(ic->pb)) {
        /* get accurate estimate from the PTSes */
        av_estimate_timings_from_pts(ic, old_offset);
    } else if (av_has_duration(ic)) {
        /* at least one component has timings - we use them for all
           the components */
        fill_all_stream_timings(ic);
    } else {
        /* less precise: use bitrate info */
        av_estimate_timings_from_bit_rate(ic);
    }
    av_update_stream_timings(ic);

#if 0
    {
        int i;
        AVStream *st;
        for(i = 0;i < ic->nb_streams; i++) {
            st = ic->streams[i];
        printf("%d: start_time: %0.3f duration: %0.3f\n",
               i, (double)st->start_time / AV_TIME_BASE,
               (double)st->duration / AV_TIME_BASE);
        }
        printf("stream: start_time: %0.3f duration: %0.3f bitrate=%d kb/s\n",
               (double)ic->start_time / AV_TIME_BASE,
               (double)ic->duration / AV_TIME_BASE,
               ic->bit_rate / 1000);
    }
#endif
}

static int has_codec_parameters(AVCodecContext *enc)
{
    int val;
    switch(enc->codec_type) {
    case CODEC_TYPE_AUDIO:
        val = enc->sample_rate && enc->channels;
        if(!enc->frame_size &&
           (enc->codec_id == CODEC_ID_VORBIS ||
            enc->codec_id == CODEC_ID_AAC))
            return 0;
        break;
    case CODEC_TYPE_VIDEO:
        val = enc->width && enc->pix_fmt != PIX_FMT_NONE;
        break;
    default:
        val = 1;
        break;
    }
    return enc->codec_id != CODEC_ID_NONE && val != 0;
}

static int try_decode_frame(AVStream *st, const uint8_t *data, int size)
{
    int16_t *samples;
    AVCodec *codec;
    int got_picture, data_size, ret=0;
    AVFrame picture;

  if(!st->codec->codec){
    codec = avcodec_find_decoder(st->codec->codec_id);
    if (!codec)
        return -1;
    ret = avcodec_open(st->codec, codec);
    if (ret < 0)
        return ret;
  }

  if(!has_codec_parameters(st->codec)){
    switch(st->codec->codec_type) {
    case CODEC_TYPE_VIDEO:
        ret = avcodec_decode_video(st->codec, &picture,
                                   &got_picture, data, size);
        break;
    case CODEC_TYPE_AUDIO:
        data_size = FFMAX(size, AVCODEC_MAX_AUDIO_FRAME_SIZE);
        samples = av_malloc(data_size);
        if (!samples)
            goto fail;
        ret = avcodec_decode_audio2(st->codec, samples,
                                    &data_size, data, size);
        av_free(samples);
        break;
    default:
        break;
    }
  }
 fail:
    return ret;
}

unsigned int codec_get_tag(const AVCodecTag *tags, int id)
{
    while (tags->id != CODEC_ID_NONE) {
        if (tags->id == id)
            return tags->tag;
        tags++;
    }
    return 0;
}

enum CodecID codec_get_id(const AVCodecTag *tags, unsigned int tag)
{
    int i;
    for(i=0; tags[i].id != CODEC_ID_NONE;i++) {
        if(tag == tags[i].tag)
            return tags[i].id;
    }
    for(i=0; tags[i].id != CODEC_ID_NONE; i++) {
        if(   toupper((tag >> 0)&0xFF) == toupper((tags[i].tag >> 0)&0xFF)
           && toupper((tag >> 8)&0xFF) == toupper((tags[i].tag >> 8)&0xFF)
           && toupper((tag >>16)&0xFF) == toupper((tags[i].tag >>16)&0xFF)
           && toupper((tag >>24)&0xFF) == toupper((tags[i].tag >>24)&0xFF))
            return tags[i].id;
    }
    return CODEC_ID_NONE;
}

unsigned int av_codec_get_tag(const AVCodecTag *tags[4], enum CodecID id)
{
    int i;
    for(i=0; tags && tags[i]; i++){
        int tag= codec_get_tag(tags[i], id);
        if(tag) return tag;
    }
    return 0;
}

enum CodecID av_codec_get_id(const AVCodecTag *tags[4], unsigned int tag)
{
    int i;
    for(i=0; tags && tags[i]; i++){
        enum CodecID id= codec_get_id(tags[i], tag);
        if(id!=CODEC_ID_NONE) return id;
    }
    return CODEC_ID_NONE;
}

static void compute_chapters_end(AVFormatContext *s)
{
    unsigned int i;

    for (i=0; i+1<s->nb_chapters; i++)
        if (s->chapters[i]->end == AV_NOPTS_VALUE) {
            assert(s->chapters[i]->start <= s->chapters[i+1]->start);
            assert(!av_cmp_q(s->chapters[i]->time_base, s->chapters[i+1]->time_base));
            s->chapters[i]->end = s->chapters[i+1]->start;
        }

    if (s->nb_chapters && s->chapters[i]->end == AV_NOPTS_VALUE) {
        assert(s->start_time != AV_NOPTS_VALUE);
        assert(s->duration > 0);
        s->chapters[i]->end = av_rescale_q(s->start_time + s->duration,
                                           AV_TIME_BASE_Q,
                                           s->chapters[i]->time_base);
    }
}

/* absolute maximum size we read until we abort */
#define MAX_READ_SIZE        5000000

#define MAX_STD_TIMEBASES (60*12+5)
static int get_std_framerate(int i){
#ifndef __CW32__
    if(i<60*12) return i*1001;
    else        return ((int[]){24,30,60,12,15})[i-60*12]*1000*12;
#else
	const int t[] = {24,30,60,12,15};
    if(i<60*12) return i*1001;
    else        return t[i-60*12]*1000*12;
#endif
}

/*
 * Is the time base unreliable.
 * This is a heuristic to balance between quick acceptance of the values in
 * the headers vs. some extra checks.
 * Old DivX and Xvid often have nonsense timebases like 1fps or 2fps.
 * MPEG-2 commonly misuses field repeat flags to store different framerates.
 * And there are "variable" fps files this needs to detect as well.
 */
static int tb_unreliable(AVCodecContext *c){
    if(   c->time_base.den >= 101L*c->time_base.num
       || c->time_base.den <    5L*c->time_base.num
/*       || c->codec_tag == ff_get_fourcc("DIVX")
       || c->codec_tag == ff_get_fourcc("XVID")*/
       || c->codec_id == CODEC_ID_MPEG2VIDEO)
        return 1;
    return 0;
}

int av_find_stream_info(AVFormatContext *ic)
{
    int i, count, ret, read_size, j;
    AVStream *st;
    AVPacket pkt1, *pkt;
    int64_t last_dts[MAX_STREAMS];
    int duration_count[MAX_STREAMS]={0};
    double (*duration_error)[MAX_STD_TIMEBASES];
    offset_t old_offset = url_ftell(ic->pb);
    int64_t codec_info_duration[MAX_STREAMS]={0};
    int codec_info_nb_frames[MAX_STREAMS]={0};

    duration_error = av_mallocz(MAX_STREAMS * sizeof(*duration_error));
    if (!duration_error) return AVERROR(ENOMEM);

    for(i=0;i<ic->nb_streams;i++) {
        st = ic->streams[i];
        if(st->codec->codec_type == CODEC_TYPE_VIDEO){
/*            if(!st->time_base.num)
                st->time_base= */
            if(!st->codec->time_base.num)
                st->codec->time_base= st->time_base;
        }
        //only for the split stuff
        if (!st->parser) {
            st->parser = av_parser_init(st->codec->codec_id);
            if(st->need_parsing == AVSTREAM_PARSE_HEADERS && st->parser){
                st->parser->flags |= PARSER_FLAG_COMPLETE_FRAMES;
            }
        }
    }

    for(i=0;i<MAX_STREAMS;i++){
        last_dts[i]= AV_NOPTS_VALUE;
    }

    count = 0;
    read_size = 0;
    for(;;) {
        /* check if one codec still needs to be handled */
        for(i=0;i<ic->nb_streams;i++) {
            st = ic->streams[i];
            if (!has_codec_parameters(st->codec))
                break;
            /* variable fps and no guess at the real fps */
            if(   tb_unreliable(st->codec)
               && duration_count[i]<20 && st->codec->codec_type == CODEC_TYPE_VIDEO)
                break;
            if(st->parser && st->parser->parser->split && !st->codec->extradata)
                break;
            if(st->first_dts == AV_NOPTS_VALUE)
                break;
        }
        if (i == ic->nb_streams) {
            /* NOTE: if the format has no header, then we need to read
               some packets to get most of the streams, so we cannot
               stop here */
            if (!(ic->ctx_flags & AVFMTCTX_NOHEADER)) {
                /* if we found the info for all the codecs, we can stop */
                ret = count;
                break;
            }
        }
        /* we did not get all the codec info, but we read too much data */
        if (read_size >= MAX_READ_SIZE) {
            ret = count;
            break;
        }

        /* NOTE: a new stream can be added there if no header in file
           (AVFMTCTX_NOHEADER) */
        ret = av_read_frame_internal(ic, &pkt1);
        if (ret < 0) {
            /* EOF or error */
            ret = -1; /* we could not have all the codec parameters before EOF */
            for(i=0;i<ic->nb_streams;i++) {
                st = ic->streams[i];
                if (!has_codec_parameters(st->codec)){
                    char buf[256];
                    avcodec_string(buf, sizeof(buf), st->codec, 0);
                    av_log(ic, AV_LOG_INFO, "Could not find codec parameters (%s)\n", buf);
                } else {
                    ret = 0;
                }
            }
            break;
        }

        pkt= add_to_pktbuf(&ic->packet_buffer, &pkt1);
        if(av_dup_packet(pkt) < 0)
            return AVERROR(ENOMEM);

        read_size += pkt->size;

        st = ic->streams[pkt->stream_index];
        if(codec_info_nb_frames[st->index]>1)
            codec_info_duration[st->index] += pkt->duration;
        if (pkt->duration != 0)
            codec_info_nb_frames[st->index]++;

        {
            int index= pkt->stream_index;
            int64_t last= last_dts[index];
            int64_t duration= pkt->dts - last;

            if(pkt->dts != AV_NOPTS_VALUE && last != AV_NOPTS_VALUE && duration>0){
                double dur= duration * av_q2d(st->time_base);

//                if(st->codec->codec_type == CODEC_TYPE_VIDEO)
//                    av_log(NULL, AV_LOG_ERROR, "%f\n", dur);
                if(duration_count[index] < 2)
                    memset(duration_error[index], 0, sizeof(*duration_error));
                for(i=1; i<MAX_STD_TIMEBASES; i++){
                    int framerate= get_std_framerate(i);
                    int ticks= lrintf(dur*framerate/(1001*12));
                    double error= dur - ticks*1001*12/(double)framerate;
                    duration_error[index][i] += error*error;
                }
                duration_count[index]++;
            }
            if(last == AV_NOPTS_VALUE || duration_count[index]<=1)
                last_dts[pkt->stream_index]= pkt->dts;
        }
        if(st->parser && st->parser->parser->split && !st->codec->extradata){
            int i= st->parser->parser->split(st->codec, pkt->data, pkt->size);
            if(i){
                st->codec->extradata_size= i;
                st->codec->extradata= av_malloc(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
                memcpy(st->codec->extradata, pkt->data, st->codec->extradata_size);
                memset(st->codec->extradata + i, 0, FF_INPUT_BUFFER_PADDING_SIZE);
            }
        }

        /* if still no information, we try to open the codec and to
           decompress the frame. We try to avoid that in most case