ffmpeg.c

ffmpeg源码分析

                    enc->coded_frame->quality/(float)FF_QP2LAMBDA);
        }
        if (!vid && enc->codec_type == CODEC_TYPE_VIDEO) {
            frame_number = ost->frame_number;
            snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "frame=%5d q=%3.1f ",
                    frame_number, enc->coded_frame ? enc->coded_frame->quality/(float)FF_QP2LAMBDA : -1);
            if(is_last_report)
                snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "L");
            if(qp_hist && enc->coded_frame){
                int j;
                int qp= lrintf(enc->coded_frame->quality/(float)FF_QP2LAMBDA);
                if(qp>=0 && qp<sizeof(qp_histogram)/sizeof(int))
                    qp_histogram[qp]++;
                for(j=0; j<32; j++)
                    snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "%X", (int)lrintf(log(qp_histogram[j]+1)/log(2)));
            }
            if (enc->flags&CODEC_FLAG_PSNR){
                int j;
                double error, error_sum=0;
                double scale, scale_sum=0;
                char type[3]= {'Y','U','V'};
                snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "PSNR=");
                for(j=0; j<3; j++){
                    if(is_last_report){
                        error= enc->error[j];
                        scale= enc->width*enc->height*255.0*255.0*frame_number;
                    }else{
                        error= enc->coded_frame->error[j];
                        scale= enc->width*enc->height*255.0*255.0;
                    }
                    if(j) scale/=4;
                    error_sum += error;
                    scale_sum += scale;
                    snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "%c:%2.2f ", type[j], psnr(error/scale));
                }
                snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "*:%2.2f ", psnr(error_sum/scale_sum));
            }
            vid = 1;
        }
        /* compute min output value */
        pts = (double)ost->st->pts.val * ost->st->time_base.num / ost->st->time_base.den;
        if ((pts < ti1) && (pts > 0))
            ti1 = pts;
    }
    if (ti1 < 0.01)
        ti1 = 0.01;

    if (verbose || is_last_report) {
        bitrate = (double)(total_size * 8) / ti1 / 1000.0;

        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
            "size=%8.0fkB time=%0.1f bitrate=%6.1fkbits/s",
            (double)total_size / 1024, ti1, bitrate);

        if (verbose > 1)
          snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), " dup=%d drop=%d",
                  nb_frames_dup, nb_frames_drop);

        if (verbose >= 0)
            fprintf(stderr, "%s    \r", buf);

        fflush(stderr);
    }

    if (is_last_report && verbose >= 0){
        int64_t raw= audio_size + video_size + extra_size;
        fprintf(stderr, "\n");
        fprintf(stderr, "video:%1.0fkB audio:%1.0fkB global headers:%1.0fkB muxing overhead %f%%\n",
                video_size/1024.0,
                audio_size/1024.0,
                extra_size/1024.0,
                100.0*(total_size - raw)/raw
        );
    }
}

/* pkt = NULL means EOF (needed to flush decoder buffers) */
static int output_packet(AVInputStream *ist, int ist_index,
                         AVOutputStream **ost_table, int nb_ostreams,
                         const AVPacket *pkt)
{
    AVFormatContext *os;
    AVOutputStream *ost;
    uint8_t *ptr;
    int len, ret, i;
    uint8_t *data_buf;
    int data_size, got_picture;
    AVFrame picture;
    void *buffer_to_free;
    static unsigned int samples_size= 0;
    static short *samples= NULL;
    AVSubtitle subtitle, *subtitle_to_free;
    int got_subtitle;

    if(!pkt){
        ist->pts= ist->next_pts; // needed for last packet if vsync=0
    } else if (pkt->dts != AV_NOPTS_VALUE) { //FIXME seems redundant, as libavformat does this too
        ist->next_pts = ist->pts = av_rescale_q(pkt->dts, ist->st->time_base, AV_TIME_BASE_Q);
    } else {
//        assert(ist->pts == ist->next_pts);
    }

    if (pkt == NULL) {
        /* EOF handling */
        ptr = NULL;
        len = 0;
        goto handle_eof;
    }

    len = pkt->size;
    ptr = pkt->data;
    while (len > 0) {
    handle_eof:
        /* decode the packet if needed */
        data_buf = NULL; /* fail safe */
        data_size = 0;
        subtitle_to_free = NULL;
        if (ist->decoding_needed) {
            switch(ist->st->codec->codec_type) {
            case CODEC_TYPE_AUDIO:{
                if(pkt)
                    samples= av_fast_realloc(samples, &samples_size, FFMAX(pkt->size, AVCODEC_MAX_AUDIO_FRAME_SIZE));
                    /* XXX: could avoid copy if PCM 16 bits with same
                       endianness as CPU */
                ret = avcodec_decode_audio(ist->st->codec, samples, &data_size,
                                           ptr, len);
                if (ret < 0)
                    goto fail_decode;
                ptr += ret;
                len -= ret;
                /* Some bug in mpeg audio decoder gives */
                /* data_size < 0, it seems they are overflows */
                if (data_size <= 0) {
                    /* no audio frame */
                    continue;
                }
                data_buf = (uint8_t *)samples;
                ist->next_pts += ((int64_t)AV_TIME_BASE/2 * data_size) /
                    (ist->st->codec->sample_rate * ist->st->codec->channels);
                break;}
            case CODEC_TYPE_VIDEO:
                    data_size = (ist->st->codec->width * ist->st->codec->height * 3) / 2;
                    /* XXX: allocate picture correctly */
                    avcodec_get_frame_defaults(&picture);

                    ret = avcodec_decode_video(ist->st->codec,
                                               &picture, &got_picture, ptr, len);
                    ist->st->quality= picture.quality;
                    if (ret < 0)
                        goto fail_decode;
                    if (!got_picture) {
                        /* no picture yet */
                        goto discard_packet;
                    }
                    if (ist->st->codec->time_base.num != 0) {
                        ist->next_pts += ((int64_t)AV_TIME_BASE *
                                          ist->st->codec->time_base.num) /
                            ist->st->codec->time_base.den;
                    }
                    len = 0;
                    break;
            case CODEC_TYPE_SUBTITLE:
                ret = avcodec_decode_subtitle(ist->st->codec,
                                              &subtitle, &got_subtitle, ptr, len);
                if (ret < 0)
                    goto fail_decode;
                if (!got_subtitle) {
                    goto discard_packet;
                }
                subtitle_to_free = &subtitle;
                len = 0;
                break;
            default:
                goto fail_decode;
            }
        } else {
                switch(ist->st->codec->codec_type) {
                case CODEC_TYPE_AUDIO:
                    ist->next_pts += ((int64_t)AV_TIME_BASE * ist->st->codec->frame_size) /
                        (ist->st->codec->sample_rate * ist->st->codec->channels);
                    break;
                case CODEC_TYPE_VIDEO:
                    if (ist->st->codec->time_base.num != 0) {
                        ist->next_pts += ((int64_t)AV_TIME_BASE *
                                          ist->st->codec->time_base.num) /
                            ist->st->codec->time_base.den;
                    }
                    break;
                }
                data_buf = ptr;
                data_size = len;
                ret = len;
                len = 0;
            }

            buffer_to_free = NULL;
            if (ist->st->codec->codec_type == CODEC_TYPE_VIDEO) {
                pre_process_video_frame(ist, (AVPicture *)&picture,
                                        &buffer_to_free);
            }

            // preprocess audio (volume)
            if (ist->st->codec->codec_type == CODEC_TYPE_AUDIO) {
                if (audio_volume != 256) {
                    short *volp;
                    volp = samples;
                    for(i=0;i<(data_size / sizeof(short));i++) {
                        int v = ((*volp) * audio_volume + 128) >> 8;
                        if (v < -32768) v = -32768;
                        if (v >  32767) v = 32767;
                        *volp++ = v;
                    }
                }
            }

            /* frame rate emulation */
            if (ist->st->codec->rate_emu) {
                int64_t pts = av_rescale((int64_t) ist->frame * ist->st->codec->time_base.num, 1000000, ist->st->codec->time_base.den);
                int64_t now = av_gettime() - ist->start;
                if (pts > now)
                    usleep(pts - now);

                ist->frame++;
            }

#if 0
            /* mpeg PTS deordering : if it is a P or I frame, the PTS
               is the one of the next displayed one */
            /* XXX: add mpeg4 too ? */
            if (ist->st->codec->codec_id == CODEC_ID_MPEG1VIDEO) {
                if (ist->st->codec->pict_type != B_TYPE) {
                    int64_t tmp;
                    tmp = ist->last_ip_pts;
                    ist->last_ip_pts  = ist->frac_pts.val;
                    ist->frac_pts.val = tmp;
                }
            }
#endif
            /* if output time reached then transcode raw format,
               encode packets and output them */
            if (start_time == 0 || ist->pts >= start_time)
                for(i=0;i<nb_ostreams;i++) {
                    int frame_size;

                    ost = ost_table[i];
                    if (ost->source_index == ist_index) {
                        os = output_files[ost->file_index];

#if 0
                        printf("%d: got pts=%0.3f %0.3f\n", i,
                               (double)pkt->pts / AV_TIME_BASE,
                               ((double)ist->pts / AV_TIME_BASE) -
                               ((double)ost->st->pts.val * ost->st->time_base.num / ost->st->time_base.den));
#endif
                        /* set the input output pts pairs */
                        //ost->sync_ipts = (double)(ist->pts + input_files_ts_offset[ist->file_index] - start_time)/ AV_TIME_BASE;

                        if (ost->encoding_needed) {
                            switch(ost->st->codec->codec_type) {
                            case CODEC_TYPE_AUDIO:
                                do_audio_out(os, ost, ist, data_buf, data_size);
                                break;
                            case CODEC_TYPE_VIDEO:
                                    do_video_out(os, ost, ist, &picture, &frame_size);
                                    video_size += frame_size;
                                    if (do_vstats && frame_size)
                                        do_video_stats(os, ost, frame_size);
                                break;
                            case CODEC_TYPE_SUBTITLE:
                                do_subtitle_out(os, ost, ist, &subtitle,
                                                pkt->pts);
                                break;
                            default:
                                av_abort();
                            }
                        } else {
                            AVFrame avframe; //FIXME/XXX remove this
                            AVPacket opkt;
                            av_init_packet(&opkt);

                            /* no reencoding needed : output the packet directly */
                            /* force the input stream PTS */

                            avcodec_get_frame_defaults(&avframe);
                            ost->st->codec->coded_frame= &avframe;
                            avframe.key_frame = pkt->flags & PKT_FLAG_KEY;

                            if(ost->st->codec->codec_type == CODEC_TYPE_AUDIO)
                                audio_size += data_size;
                            else if (ost->st->codec->codec_type == CODEC_TYPE_VIDEO) {
                                video_size += data_size;
                                ost->sync_opts++;
                            }

                            opkt.stream_index= ost->index;
                            if(pkt->pts != AV_NOPTS_VALUE)
                                opkt.pts= av_rescale_q(av_rescale_q(pkt->pts, ist->st->time_base, AV_TIME_BASE_Q) + input_files_ts_offset[ist->file_index], AV_TIME_BASE_Q,  ost->st->time_base);
                            else
                                opkt.pts= AV_NOPTS_VALUE;

                            {
                                int64_t dts;
                                if (pkt->dts == AV_NOPTS_VALUE)
                                    dts = ist->next_pts;
                                else
                                    dts= av_rescale_q(pkt->dts, ist->st->time_base, AV_TIME_BASE_Q);
                                opkt.dts= av_rescale_q(dts + input_files_ts_offset[ist->file_index], AV_TIME_BASE_Q,  ost->st->time_base);
                            }
                            opkt.flags= pkt->flags;
                            if(av_parser_change(ist->st->parser, ost->st->codec, &opkt.data, &opkt.size, data_buf, data_size, pkt->flags & PKT_FLAG_KEY))
                                opkt.destruct= av_destruct_packet;
                            av_interleaved_write_frame(os, &opkt);
                            ost->st->codec->frame_number++;
                            ost->frame_number++;
                            av_free_packet(&opkt);
                        }
                    }
                }
            av_free(buffer_to_free);
            /* XXX: allocate the subtitles in the codec ? */
            if (subtitle_to_free) {
                if (subtitle_to_free->rects != NULL) {
                    for (i = 0; i < subtitle_to_free->num_rects; i++) {
                        av_free(subtitle_to_free->rects[i].bitmap);
                        av_free(subtitle_to_free->rects[i].rgba_palette);
                    }
                    av_freep(&subtitle_to_free->rects);
                }
                subtitle_to_free->num_rects = 0;
                subtitle_to_free = NULL;
            }
        }
 discard_packet:
    if (pkt == NULL) {
        /* EOF handling */

        for(i=0;i<nb_ostreams;i++) {
            ost = ost_table[i];
            if (ost->source_index == ist_index) {
                AVCodecContext *enc= ost->st->codec;
                os = output_files[ost->file_index];

                if(ost->st->codec->codec_type == CODEC_TYPE_AUDIO && enc->frame_size <=1)
                    continue;
                if(ost->st->codec->codec_type == CODEC_TYPE_VIDEO && (os->oformat->flags & AVFMT_RAWPICTURE))
                    continue;

                if (ost->encoding_needed) {
                    for(;;) {
                        AVPacket pkt;
                        av_init_packet(&pkt);
                        pkt.stream_index= ost->index;

                        switch(ost->st->codec->codec_type) {
                        case CODEC_TYPE_AUDIO:
                            ret = avcodec_encode_audio(enc, bit_buffer, bit_buffer_size, NULL);
                            audio_size += ret;
                            pkt.flags |= PKT_FLAG_KEY;