ffmpeg print_report說明： 一轉一

聲明：轉帖時請註明出處

版本：ffmpeg 3.0

ffmpeg version 3.0-static Copyright (c) 2000-2016 the FFmpeg developers

print_report代碼：

static void print_report(int is_last_report, int64_t timer_start, int64_t cur_time)
{
    char buf[1024];
    AVBPrint buf_script;
    OutputStream *ost;
    AVFormatContext *oc;
    int64_t total_size;
    AVCodecContext *enc;
    int frame_number, vid, i;
    double bitrate;
    double speed;
    int64_t pts = INT64_MIN + 1;
    static int64_t last_time = -1;
    static int qp_histogram[52];
    int hours, mins, secs, us;
    int ret;
    float t;

    if (!print_stats && !is_last_report && !progress_avio)
        return;

    if (!is_last_report) {
        if (last_time == -1) {
            last_time = cur_time;
            return;
        }
        if ((cur_time - last_time) < 500000)
            return;
        last_time = cur_time;
    }

    t = (cur_time-timer_start) / 1000000.0;


    oc = output_files[0]->ctx;

    total_size = avio_size(oc->pb);
    if (total_size <= 0) // FIXME improve avio_size() so it works with non seekable output too
        total_size = avio_tell(oc->pb);

    buf[0] = '\0';
    vid = 0;
    av_bprint_init(&buf_script, 0, 1);
    for (i = 0; i < nb_output_streams; i++) {
        float q = -1;
        ost = output_streams[i];
        enc = ost->enc_ctx;
        if (!ost->stream_copy)
            q = ost->quality / (float) FF_QP2LAMBDA;

        if (vid && enc->codec_type == AVMEDIA_TYPE_VIDEO) {
            snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "q=%2.1f ", q);
            av_bprintf(&buf_script, "stream_%d_%d_q=%.1f\n",
                       ost->file_index, ost->index, q);
        }
        if (!vid && enc->codec_type == AVMEDIA_TYPE_VIDEO) {
            float fps;

            frame_number = ost->frame_number;
            fps = t > 1 ? frame_number / t : 0;
            snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "frame=%5d fps=%3.*f q=%3.1f ",
                     frame_number, fps < 9.95, fps, q);
            av_bprintf(&buf_script, "frame=%d\n", frame_number);
            av_bprintf(&buf_script, "fps=%.1f\n", fps);
            av_bprintf(&buf_script, "stream_%d_%d_q=%.1f\n",
                       ost->file_index, ost->index, q);
            if (is_last_report)
                snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "L");
            if (qp_hist) {
                int j;
                int qp = lrintf(q);
                if (qp >= 0 && qp < FF_ARRAY_ELEMS(qp_histogram))
                    qp_histogram[qp]++;
                for (j = 0; j < 32; j++)
                    snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "%X", av_log2(qp_histogram[j] + 1));
            }

            if ((enc->flags & AV_CODEC_FLAG_PSNR) && (ost->pict_type != AV_PICTURE_TYPE_NONE || is_last_report)) {
                int j;
                double error, error_sum = 0;
                double scale, scale_sum = 0;
                double p;
                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 = ost->error[j];
                        scale = enc->width * enc->height * 255.0 * 255.0;
                    }
                    if (j)
                        scale /= 4;
                    error_sum += error;
                    scale_sum += scale;
                    p = psnr(error / scale);
                    snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "%c:%2.2f ", type[j], p);
                    av_bprintf(&buf_script, "stream_%d_%d_psnr_%c=%2.2f\n",
                               ost->file_index, ost->index, type[j] | 32, p);
                }
                p = psnr(error_sum / scale_sum);
                snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "*:%2.2f ", psnr(error_sum / scale_sum));
                av_bprintf(&buf_script, "stream_%d_%d_psnr_all=%2.2f\n",
                           ost->file_index, ost->index, p);
            }
            vid = 1;
        }
        /* compute min output value */
        if (av_stream_get_end_pts(ost->st) != AV_NOPTS_VALUE)
            pts = FFMAX(pts, av_rescale_q(av_stream_get_end_pts(ost->st),
                                          ost->st->time_base, AV_TIME_BASE_Q));
        if (is_last_report)
            nb_frames_drop += ost->last_dropped;
    }

    secs = FFABS(pts) / AV_TIME_BASE;
    us = FFABS(pts) % AV_TIME_BASE;
    mins = secs / 60;
    secs %= 60;
    hours = mins / 60;
    mins %= 60;

    bitrate = pts && total_size >= 0 ? total_size * 8 / (pts / 1000.0) : -1;
    speed = t != 0.0 ? (double)pts / AV_TIME_BASE / t : -1;

    if (total_size < 0) snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
                                 "size=N/A time=");
    else                snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
                                 "size=%8.0fkB time=", total_size / 1024.0);
    if (pts < 0)
        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "-");
    snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
             "%02d:%02d:%02d.%02d ", hours, mins, secs,
             (100 * us) / AV_TIME_BASE);

    if (bitrate < 0) {
        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),"bitrate=N/A");
        av_bprintf(&buf_script, "bitrate=N/A\n");
    }else{
        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),"bitrate=%6.1fkbits/s", bitrate);
        av_bprintf(&buf_script, "bitrate=%6.1fkbits/s\n", bitrate);
    }

    if (total_size < 0) av_bprintf(&buf_script, "total_size=N/A\n");
    else                av_bprintf(&buf_script, "total_size=%"PRId64"\n", total_size);
    av_bprintf(&buf_script, "out_time_ms=%"PRId64"\n", pts);
    av_bprintf(&buf_script, "out_time=%02d:%02d:%02d.%06d\n",
               hours, mins, secs, us);

    if (nb_frames_dup || nb_frames_drop)
        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), " dup=%d drop=%d",
                nb_frames_dup, nb_frames_drop);
    av_bprintf(&buf_script, "dup_frames=%d\n", nb_frames_dup);
    av_bprintf(&buf_script, "drop_frames=%d\n", nb_frames_drop);

    if (speed < 0) {
        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf)," speed=N/A");
        av_bprintf(&buf_script, "speed=N/A\n");
    } else {
        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf)," speed=%4.3gx", speed);
        av_bprintf(&buf_script, "speed=%4.3gx\n", speed);
    }

    if (print_stats || is_last_report) {
        const char end = is_last_report ? '\n' : '\r';
        if (print_stats==1 && AV_LOG_INFO > av_log_get_level()) {
            fprintf(stderr, "%s    %c", buf, end);
        } else
            av_log(NULL, AV_LOG_INFO, "%s    %c", buf, end);

    fflush(stderr);
    }

    if (progress_avio) {
        av_bprintf(&buf_script, "progress=%s\n",
                   is_last_report ? "end" : "continue");
        avio_write(progress_avio, buf_script.str,
                   FFMIN(buf_script.len, buf_script.size - 1));
        avio_flush(progress_avio);
        av_bprint_finalize(&buf_script, NULL);
        if (is_last_report) {
            if ((ret = avio_closep(&progress_avio)) < 0)
                av_log(NULL, AV_LOG_ERROR,
                       "Error closing progress log, loss of information possible: %s\n", av_err2str(ret));
        }
    }

    if (is_last_report)
        print_final_stats(total_size);
}

 

一轉一日誌

例如：

./ffmpeg -i test_2.flv -vcodec libx264 -b:v 300000 -r 10 -report -y -f flv test_1out.flv

 

frame=   58 fps=0.0 q=26.0 size=      98kB time=00:00:05.61 bitrate= 142.9kbits/s dup=0 drop=27 speed=11.2x

... ...

frame=   85 fps= 84 q=25.0 size=     222kB time=00:00:08.30 bitrate= 218.7kbits/s dup=0 drop=41 speed=8.25x

... ...

[libx264 @ 0x3a7c540] frame= 103 QP=24.06 NAL=2 Slice:P Poc:4   I:1    P:58   SKIP:1005 size=216 bytes

frame=  104 fps= 57 q=26.0 Lsize=     566kB time=00:00:10.30 bitrate= 450.5kbits/s dup=0 drop=50 speed=5.68x

video:397kB audio:160kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.571039%
Input file #0 (test_2.flv):
  Input stream #0:0 (video): 156 packets read (684497 bytes); 155 frames decoded;
  Input stream #0:1 (audio): 443 packets read (82827 bytes); 442 frames decoded (452608 samples);
  Total: 599 packets (767324 bytes) demuxed
Output file #0 (test_1out.flv):
  Output stream #0:0 (video): 104 frames encoded; 104 packets muxed (406830 bytes);
  Output stream #0:1 (audio): 392 frames encoded (451584 samples); 393 packets muxed (164257 bytes);
  Total: 497 packets (571087 bytes) muxed
597 frames successfully decoded, 0 decoding errors

 

其中打印信息，每項含義

frame=  104 fps= 57 q=26.0 Lsize=     566kB time=00:00:10.30 bitrate= 450.5kbits/s dup=0 drop=50 speed=5.68x

frame: 編碼的幀數量

fps：每秒編碼的幀數

q：質量因子

size：視頻和音頻編碼後的大小(我的理解)，即 Lsize=     566kB ，基本等於 video:397kB 和audio:160kB 之和

time：輸出幀的顯示時間

bitrate：輸出視頻的幀率

dup：輸入幀dupliate的數量

drop：輸入幀drop的個數

speed：編碼速度

由於源流的輸入幀率爲15，輸出幀率爲10。因此輸入幀數和輸出幀數的比例爲1.5:1.

從日誌看出輸入解碼幀爲155，輸出編碼幀104，即丟棄51幀，因此比例基本爲1.5:1。

其中系統每500ms打印一次，即

if (!is_last_report) {
        if (last_time == -1) {
            last_time = cur_time;
            return;
        }
        if ((cur_time - last_time) < 500000)
            return;
        last_time = cur_time;
    }

其中q的計算過程：

float q = -1;
        ost = output_streams[i];
        enc = ost->enc_ctx;
        if (!ost->stream_copy)
            q = ost->quality / (float) FF_QP2LAMBDA;