path: root/fftools/ffmpeg_enc.c

/*
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <math.h>
#include <stdint.h>

#include "ffmpeg.h"

#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/avutil.h"
#include "libavutil/dict.h"
#include "libavutil/display.h"
#include "libavutil/eval.h"
#include "libavutil/frame.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/log.h"
#include "libavutil/mem.h"
#include "libavutil/pixdesc.h"
#include "libavutil/rational.h"
#include "libavutil/time.h"
#include "libavutil/timestamp.h"

#include "libavcodec/avcodec.h"

struct Encoder {
    const AVClass *class;
    void          *log_parent;
    char           log_name[32];

    // combined size of all the packets received from the encoder
    uint64_t data_size;

    // number of packets received from the encoder
    uint64_t packets_encoded;

    int opened;
    int attach_par;

    Scheduler      *sch;
    unsigned        sch_idx;
};

// data that is local to the decoder thread and not visible outside of it
typedef struct EncoderThread {
    AVFrame *frame;
    AVPacket  *pkt;
} EncoderThread;

void enc_free(Encoder **penc)
{
    Encoder *enc = *penc;

    if (!enc)
        return;

    av_freep(penc);
}

static const char *enc_item_name(void *obj)
{
    const Encoder *e = obj;

    return e->log_name;
}

static const AVClass enc_class = {
    .class_name                = "Encoder",
    .version                   = LIBAVUTIL_VERSION_INT,
    .parent_log_context_offset = offsetof(Encoder, log_parent),
    .item_name                 = enc_item_name,
};

int enc_alloc(Encoder **penc, const AVCodec *codec,
              Scheduler *sch, unsigned sch_idx, void *log_parent)
{
    Encoder *enc;

    *penc = NULL;

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

    enc->class      = &enc_class;
    enc->log_parent = log_parent;

    enc->sch     = sch;
    enc->sch_idx = sch_idx;

    snprintf(enc->log_name, sizeof(enc->log_name), "enc:%s", codec->name);

    *penc = enc;

    return 0;
}

static int hw_device_setup_for_encode(Encoder *e, AVCodecContext *enc_ctx,
                                      AVBufferRef *frames_ref)
{
    const AVCodecHWConfig *config;
    HWDevice *dev = NULL;

    if (frames_ref &&
        ((AVHWFramesContext*)frames_ref->data)->format ==
        enc_ctx->pix_fmt) {
        // Matching format, will try to use hw_frames_ctx.
    } else {
        frames_ref = NULL;
    }

    for (int i = 0;; i++) {
        config = avcodec_get_hw_config(enc_ctx->codec, i);
        if (!config)
            break;

        if (frames_ref &&
            config->methods & AV_CODEC_HW_CONFIG_METHOD_HW_FRAMES_CTX &&
            (config->pix_fmt == AV_PIX_FMT_NONE ||
             config->pix_fmt == enc_ctx->pix_fmt)) {
            av_log(e, AV_LOG_VERBOSE, "Using input "
                   "frames context (format %s) with %s encoder.\n",
                   av_get_pix_fmt_name(enc_ctx->pix_fmt),
                   enc_ctx->codec->name);
            enc_ctx->hw_frames_ctx = av_buffer_ref(frames_ref);
            if (!enc_ctx->hw_frames_ctx)
                return AVERROR(ENOMEM);
            return 0;
        }

        if (!dev &&
            config->methods & AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX)
            dev = hw_device_get_by_type(config->device_type);
    }

    if (dev) {
        av_log(e, AV_LOG_VERBOSE, "Using device %s "
               "(type %s) with %s encoder.\n", dev->name,
               av_hwdevice_get_type_name(dev->type), enc_ctx->codec->name);
        enc_ctx->hw_device_ctx = av_buffer_ref(dev->device_ref);
        if (!enc_ctx->hw_device_ctx)
            return AVERROR(ENOMEM);
    } else {
        // No device required, or no device available.
    }
    return 0;
}

int enc_open(void *opaque, const AVFrame *frame)
{
    OutputStream *ost = opaque;
    InputStream *ist = ost->ist;
    Encoder              *e = ost->enc;
    AVCodecContext *enc_ctx = ost->enc_ctx;
    Decoder            *dec = NULL;
    const AVCodec      *enc = enc_ctx->codec;
    OutputFile          *of = ost->file;
    FrameData *fd;
    int frame_samples = 0;
    int ret;

    if (e->opened)
        return 0;

    // frame is always non-NULL for audio and video
    av_assert0(frame || (enc->type != AVMEDIA_TYPE_VIDEO && enc->type != AVMEDIA_TYPE_AUDIO));

    if (frame) {
        av_assert0(frame->opaque_ref);
        fd = (FrameData*)frame->opaque_ref->data;

        for (int i = 0; i < frame->nb_side_data; i++) {
            const AVSideDataDescriptor *desc = av_frame_side_data_desc(frame->side_data[i]->type);

            if (!(desc->props & AV_SIDE_DATA_PROP_GLOBAL))
                continue;

            ret = av_frame_side_data_clone(&enc_ctx->decoded_side_data,
                                           &enc_ctx->nb_decoded_side_data,
                                           frame->side_data[i],
                                           AV_FRAME_SIDE_DATA_FLAG_UNIQUE);
            if (ret < 0)
                return ret;
        }
    }

    if (ist)
        dec = ist->decoder;

    // the timebase is chosen by filtering code
    if (ost->type == AVMEDIA_TYPE_AUDIO || ost->type == AVMEDIA_TYPE_VIDEO) {
        enc_ctx->time_base      = frame->time_base;
        enc_ctx->framerate      = fd->frame_rate_filter;
    }

    switch (enc_ctx->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        av_assert0(frame->format != AV_SAMPLE_FMT_NONE &&
                   frame->sample_rate > 0 &&
                   frame->ch_layout.nb_channels > 0);
        enc_ctx->sample_fmt     = frame->format;
        enc_ctx->sample_rate    = frame->sample_rate;
        ret = av_channel_layout_copy(&enc_ctx->ch_layout, &frame->ch_layout);
        if (ret < 0)
            return ret;

        if (ost->bits_per_raw_sample)
            enc_ctx->bits_per_raw_sample = ost->bits_per_raw_sample;
        else
            enc_ctx->bits_per_raw_sample = FFMIN(fd->bits_per_raw_sample,
                                                 av_get_bytes_per_sample(enc_ctx->sample_fmt) << 3);
        break;

    case AVMEDIA_TYPE_VIDEO: {
        av_assert0(frame->format != AV_PIX_FMT_NONE &&
                   frame->width > 0 &&
                   frame->height > 0);
        enc_ctx->width  = frame->width;
        enc_ctx->height = frame->height;
        enc_ctx->sample_aspect_ratio =
            ost->frame_aspect_ratio.num ? // overridden by the -aspect cli option
            av_mul_q(ost->frame_aspect_ratio, (AVRational){ enc_ctx->height, enc_ctx->width }) :
            frame->sample_aspect_ratio;

        enc_ctx->pix_fmt = frame->format;

        if (ost->bits_per_raw_sample)
            enc_ctx->bits_per_raw_sample = ost->bits_per_raw_sample;
        else
            enc_ctx->bits_per_raw_sample = FFMIN(fd->bits_per_raw_sample,
                                                 av_pix_fmt_desc_get(enc_ctx->pix_fmt)->comp[0].depth);

        enc_ctx->color_range            = frame->color_range;
        enc_ctx->color_primaries        = frame->color_primaries;
        enc_ctx->color_trc              = frame->color_trc;
        enc_ctx->colorspace             = frame->colorspace;
        enc_ctx->chroma_sample_location = frame->chroma_location;

        if (enc_ctx->flags & (AV_CODEC_FLAG_INTERLACED_DCT | AV_CODEC_FLAG_INTERLACED_ME) ||
            (frame->flags & AV_FRAME_FLAG_INTERLACED)
#if FFMPEG_OPT_TOP
            || ost->top_field_first >= 0
#endif
            ) {
            int top_field_first =
#if FFMPEG_OPT_TOP
                ost->top_field_first >= 0 ?
                ost->top_field_first :
#endif
                !!(frame->flags & AV_FRAME_FLAG_TOP_FIELD_FIRST);

            if (enc->id == AV_CODEC_ID_MJPEG)
                enc_ctx->field_order = top_field_first ? AV_FIELD_TT : AV_FIELD_BB;
            else
                enc_ctx->field_order = top_field_first ? AV_FIELD_TB : AV_FIELD_BT;
        } else
            enc_ctx->field_order = AV_FIELD_PROGRESSIVE;

        break;
        }
    case AVMEDIA_TYPE_SUBTITLE:
        enc_ctx->time_base = AV_TIME_BASE_Q;

        if (!enc_ctx->width) {
            enc_ctx->width     = ost->ist->par->width;
            enc_ctx->height    = ost->ist->par->height;
        }

        av_assert0(dec);
        if (dec->subtitle_header) {
            /* ASS code assumes this buffer is null terminated so add extra byte. */
            enc_ctx->subtitle_header = av_mallocz(dec->subtitle_header_size + 1);
            if (!enc_ctx->subtitle_header)
                return AVERROR(ENOMEM);
            memcpy(enc_ctx->subtitle_header, dec->subtitle_header,
                   dec->subtitle_header_size);
            enc_ctx->subtitle_header_size = dec->subtitle_header_size;
        }

        break;
    default:
        av_assert0(0);
        break;
    }

    if (ost->bitexact)
        enc_ctx->flags |= AV_CODEC_FLAG_BITEXACT;

    if (enc->capabilities & AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE)
        enc_ctx->flags |= AV_CODEC_FLAG_COPY_OPAQUE;

    enc_ctx->flags |= AV_CODEC_FLAG_FRAME_DURATION;

    ret = hw_device_setup_for_encode(e, enc_ctx, frame ? frame->hw_frames_ctx : NULL);
    if (ret < 0) {
        av_log(e, AV_LOG_ERROR,
               "Encoding hardware device setup failed: %s\n", av_err2str(ret));
        return ret;
    }

    if ((ret = avcodec_open2(enc_ctx, enc, NULL)) < 0) {
        if (ret != AVERROR_EXPERIMENTAL)
            av_log(e, AV_LOG_ERROR, "Error while opening encoder - maybe "
                   "incorrect parameters such as bit_rate, rate, width or height.\n");
        return ret;
    }

    e->opened = 1;

    if (enc_ctx->frame_size)
        frame_samples = enc_ctx->frame_size;

    if (enc_ctx->bit_rate && enc_ctx->bit_rate < 1000 &&
        enc_ctx->codec_id != AV_CODEC_ID_CODEC2 /* don't complain about 700 bit/s modes */)
        av_log(e, AV_LOG_WARNING, "The bitrate parameter is set too low."
                                    " It takes bits/s as argument, not kbits/s\n");

    ret = of_stream_init(of, ost, enc_ctx);
    if (ret < 0)
        return ret;

    return frame_samples;
}

static int check_recording_time(OutputStream *ost, int64_t ts, AVRational tb)
{
    OutputFile *of = ost->file;

    if (of->recording_time != INT64_MAX &&
        av_compare_ts(ts, tb, of->recording_time, AV_TIME_BASE_Q) >= 0) {
        return 0;
    }
    return 1;
}

static int do_subtitle_out(OutputFile *of, OutputStream *ost, const AVSubtitle *sub,
                           AVPacket *pkt)
{
    Encoder *e = ost->enc;
    int subtitle_out_max_size = 1024 * 1024;
    int subtitle_out_size, nb, i, ret;
    AVCodecContext *enc;
    int64_t pts;

    if (sub->pts == AV_NOPTS_VALUE) {
        av_log(e, AV_LOG_ERROR, "Subtitle packets must have a pts\n");
        return exit_on_error ? AVERROR(EINVAL) : 0;
    }
    if ((of->start_time != AV_NOPTS_VALUE && sub->pts < of->start_time))
        return 0;

    enc = ost->enc_ctx;

    /* Note: DVB subtitle need one packet to draw them and one other
       packet to clear them */
    /* XXX: signal it in the codec context ? */
    if (enc->codec_id == AV_CODEC_ID_DVB_SUBTITLE)
        nb = 2;
    else if (enc->codec_id == AV_CODEC_ID_ASS)
        nb = FFMAX(sub->num_rects, 1);
    else
        nb = 1;

    /* shift timestamp to honor -ss and make check_recording_time() work with -t */
    pts = sub->pts;
    if (of->start_time != AV_NOPTS_VALUE)
        pts -= of->start_time;
    for (i = 0; i < nb; i++) {
        AVSubtitle local_sub = *sub;

        if (!check_recording_time(ost, pts, AV_TIME_BASE_Q))
            return AVERROR_EOF;

        ret = av_new_packet(pkt, subtitle_out_max_size);
        if (ret < 0)
            return AVERROR(ENOMEM);

        local_sub.pts = pts;
        // start_display_time is required to be 0
        local_sub.pts               += av_rescale_q(sub->start_display_time, (AVRational){ 1, 1000 }, AV_TIME_BASE_Q);
        local_sub.end_display_time  -= sub->start_display_time;
        local_sub.start_display_time = 0;

        if (enc->codec_id == AV_CODEC_ID_DVB_SUBTITLE && i == 1)
            local_sub.num_rects = 0;
        else if (enc->codec_id == AV_CODEC_ID_ASS && sub->num_rects > 0) {
            local_sub.num_rects = 1;
            local_sub.rects += i;
        }

        ost->frames_encoded++;

        subtitle_out_size = avcodec_encode_subtitle(enc, pkt->data, pkt->size, &local_sub);
        if (subtitle_out_size < 0) {
            av_log(e, AV_LOG_FATAL, "Subtitle encoding failed\n");
            return subtitle_out_size;
        }

        av_shrink_packet(pkt, subtitle_out_size);
        pkt->time_base = AV_TIME_BASE_Q;
        pkt->pts       = sub->pts;
        pkt->duration = av_rescale_q(sub->end_display_time, (AVRational){ 1, 1000 }, pkt->time_base);
        if (enc->codec_id == AV_CODEC_ID_DVB_SUBTITLE) {
            /* XXX: the pts correction is handled here. Maybe handling
               it in the codec would be better */
            if (i == 0)
                pkt->pts += av_rescale_q(sub->start_display_time, (AVRational){ 1, 1000 }, pkt->time_base);
            else
                pkt->pts += av_rescale_q(sub->end_display_time, (AVRational){ 1, 1000 }, pkt->time_base);
        }
        pkt->dts = pkt->pts;

        ret = sch_enc_send(e->sch, e->sch_idx, pkt);
        if (ret < 0) {
            av_packet_unref(pkt);
            return ret;
        }
    }

    return 0;
}

void enc_stats_write(OutputStream *ost, EncStats *es,
                     const AVFrame *frame, const AVPacket *pkt,
                     uint64_t frame_num)
{
    Encoder      *e = ost->enc;
    AVIOContext *io = es->io;
    AVRational   tb = frame ? frame->time_base : pkt->time_base;
    int64_t     pts = frame ? frame->pts : pkt->pts;

    AVRational  tbi = (AVRational){ 0, 1};
    int64_t    ptsi = INT64_MAX;

    const FrameData *fd = NULL;

    if (frame ? frame->opaque_ref : pkt->opaque_ref) {
        fd   = (const FrameData*)(frame ? frame->opaque_ref->data : pkt->opaque_ref->data);
        tbi  = fd->dec.tb;
        ptsi = fd->dec.pts;
    }

    pthread_mutex_lock(&es->lock);

    for (size_t i = 0; i < es->nb_components; i++) {
        const EncStatsComponent *c = &es->components[i];

        switch (c->type) {
        case ENC_STATS_LITERAL:         avio_write (io, c->str,     c->str_len);                    continue;
        case ENC_STATS_FILE_IDX:        avio_printf(io, "%d",       ost->file->index);              continue;
        case ENC_STATS_STREAM_IDX:      avio_printf(io, "%d",       ost->index);                    continue;
        case ENC_STATS_TIMEBASE:        avio_printf(io, "%d/%d",    tb.num, tb.den);                continue;
        case ENC_STATS_TIMEBASE_IN:     avio_printf(io, "%d/%d",    tbi.num, tbi.den);              continue;
        case ENC_STATS_PTS:             avio_printf(io, "%"PRId64,  pts);                           continue;
        case ENC_STATS_PTS_IN:          avio_printf(io, "%"PRId64,  ptsi);                          continue;
        case ENC_STATS_PTS_TIME:        avio_printf(io, "%g",       pts * av_q2d(tb));              continue;
        case ENC_STATS_PTS_TIME_IN:     avio_printf(io, "%g",       ptsi == INT64_MAX ?
                                                                    INFINITY : ptsi * av_q2d(tbi)); continue;
        case ENC_STATS_FRAME_NUM:       avio_printf(io, "%"PRIu64,  frame_num);                     continue;
        case ENC_STATS_FRAME_NUM_IN:    avio_printf(io, "%"PRIu64,  fd ? fd->dec.frame_num : -1);   continue;
        }

        if (frame) {
            switch (c->type) {
            case ENC_STATS_SAMPLE_NUM:  avio_printf(io, "%"PRIu64,  ost->samples_encoded);          continue;
            case ENC_STATS_NB_SAMPLES:  avio_printf(io, "%d",       frame->nb_samples);             continue;
            default: av_assert0(0);
            }
        } else {
            switch (c->type) {
            case ENC_STATS_DTS:         avio_printf(io, "%"PRId64,  pkt->dts);                      continue;
            case ENC_STATS_DTS_TIME:    avio_printf(io, "%g",       pkt->dts * av_q2d(tb));         continue;
            case ENC_STATS_PKT_SIZE:    avio_printf(io, "%d",       pkt->size);                     continue;
            case ENC_STATS_KEYFRAME:    avio_write(io, (pkt->flags & AV_PKT_FLAG_KEY) ?
                                                       "K" : "N", 1);                               continue;
            case ENC_STATS_BITRATE: {
                double duration = FFMAX(pkt->duration, 1) * av_q2d(tb);
                avio_printf(io, "%g",  8.0 * pkt->size / duration);
                continue;
            }
            case ENC_STATS_AVG_BITRATE: {
                double duration = pkt->dts * av_q2d(tb);
                avio_printf(io, "%g",  duration > 0 ? 8.0 * e->data_size / duration : -1.);
                continue;
            }
            default: av_assert0(0);
            }
        }
    }
    avio_w8(io, '\n');
    avio_flush(io);

    pthread_mutex_unlock(&es->lock);
}

static inline double psnr(double d)
{
    return -10.0 * log10(d);
}

static int update_video_stats(OutputStream *ost, const AVPacket *pkt, int write_vstats)
{
    Encoder        *e = ost->enc;
    const uint8_t *sd = av_packet_get_side_data(pkt, AV_PKT_DATA_QUALITY_STATS,
                                                NULL);
    AVCodecContext *enc = ost->enc_ctx;
    enum AVPictureType pict_type;
    int64_t frame_number;
    double ti1, bitrate, avg_bitrate;
    double psnr_val = -1;
    int quality;

    quality        = sd ? AV_RL32(sd) : -1;
    pict_type      = sd ? sd[4] : AV_PICTURE_TYPE_NONE;

    atomic_store(&ost->quality, quality);

    if ((enc->flags & AV_CODEC_FLAG_PSNR) && sd && sd[5]) {
        // FIXME the scaling assumes 8bit
        double error = AV_RL64(sd + 8) / (enc->width * enc->height * 255.0 * 255.0);
        if (error >= 0 && error <= 1)
            psnr_val = psnr(error);
    }

    if (!write_vstats)
        return 0;

    /* this is executed just the first time update_video_stats is called */
    if (!vstats_file) {
        vstats_file = fopen(vstats_filename, "w");
        if (!vstats_file) {
            perror("fopen");
            return AVERROR(errno);
        }
    }

    frame_number = e->packets_encoded;
    if (vstats_version <= 1) {
        fprintf(vstats_file, "frame= %5"PRId64" q= %2.1f ", frame_number,
                quality / (float)FF_QP2LAMBDA);
    } else  {
        fprintf(vstats_file, "out= %2d st= %2d frame= %5"PRId64" q= %2.1f ",
                ost->file->index, ost->index, frame_number,
                quality / (float)FF_QP2LAMBDA);
    }

    if (psnr_val >= 0)
        fprintf(vstats_file, "PSNR= %6.2f ", psnr_val);

    fprintf(vstats_file,"f_size= %6d ", pkt->size);
    /* compute pts value */
    ti1 = pkt->dts * av_q2d(pkt->time_base);
    if (ti1 < 0.01)
        ti1 = 0.01;

    bitrate     = (pkt->size * 8) / av_q2d(enc->time_base) / 1000.0;
    avg_bitrate = (double)(e->data_size * 8) / ti1 / 1000.0;
    fprintf(vstats_file, "s_size= %8.0fKiB time= %0.3f br= %7.1fkbits/s avg_br= %7.1fkbits/s ",
           (double)e->data_size / 1024, ti1, bitrate, avg_bitrate);
    fprintf(vstats_file, "type= %c\n", av_get_picture_type_char(pict_type));

    return 0;
}

static int encode_frame(OutputFile *of, OutputStream *ost, AVFrame *frame,
                        AVPacket *pkt)
{
    Encoder            *e = ost->enc;
    AVCodecContext   *enc = ost->enc_ctx;
    const char *type_desc = av_get_media_type_string(enc->codec_type);
    const char    *action = frame ? "encode" : "flush";
    int ret;

    if (frame) {
        FrameData *fd = frame_data(frame);

        if (!fd)
            return AVERROR(ENOMEM);

        fd->wallclock[LATENCY_PROBE_ENC_PRE] = av_gettime_relative();

        if (ost->enc_stats_pre.io)
            enc_stats_write(ost, &ost->enc_stats_pre, frame, NULL,
                            ost->frames_encoded);

        ost->frames_encoded++;
        ost->samples_encoded += frame->nb_samples;

        if (debug_ts) {
            av_log(e, AV_LOG_INFO, "encoder <- type:%s "
                   "frame_pts:%s frame_pts_time:%s time_base:%d/%d\n",
                   type_desc,
                   av_ts2str(frame->pts), av_ts2timestr(frame->pts, &enc->time_base),
                   enc->time_base.num, enc->time_base.den);
        }

        if (frame->sample_aspect_ratio.num && !ost->frame_aspect_ratio.num)
            enc->sample_aspect_ratio = frame->sample_aspect_ratio;
    }

    update_benchmark(NULL);

    ret = avcodec_send_frame(enc, frame);
    if (ret < 0 && !(ret == AVERROR_EOF && !frame)) {
        av_log(e, AV_LOG_ERROR, "Error submitting %s frame to the encoder\n",
               type_desc);
        return ret;
    }

    while (1) {
        FrameData *fd;

        av_packet_unref(pkt);

        ret = avcodec_receive_packet(enc, pkt);
        update_benchmark("%s_%s %d.%d", action, type_desc,
                         of->index, ost->index);

        pkt->time_base = enc->time_base;

        /* if two pass, output log on success and EOF */
        if ((ret >= 0 || ret == AVERROR_EOF) && ost->logfile && enc->stats_out)
            fprintf(ost->logfile, "%s", enc->stats_out);

        if (ret == AVERROR(EAGAIN)) {
            av_assert0(frame); // should never happen during flushing
            return 0;
        } else if (ret < 0) {
            if (ret != AVERROR_EOF)
                av_log(e, AV_LOG_ERROR, "%s encoding failed\n", type_desc);
            return ret;
        }

        fd = packet_data(pkt);
        if (!fd)
            return AVERROR(ENOMEM);
        fd->wallclock[LATENCY_PROBE_ENC_POST] = av_gettime_relative();

        // attach stream parameters to first packet if requested
        avcodec_parameters_free(&fd->par_enc);
        if (e->attach_par && !e->packets_encoded) {
            fd->par_enc = avcodec_parameters_alloc();
            if (!fd->par_enc)
                return AVERROR(ENOMEM);

            ret = avcodec_parameters_from_context(fd->par_enc, enc);
            if (ret < 0)
                return ret;
        }

        pkt->flags |= AV_PKT_FLAG_TRUSTED;

        if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
            ret = update_video_stats(ost, pkt, !!vstats_filename);
            if (ret < 0)
                return ret;
        }

        if (ost->enc_stats_post.io)
            enc_stats_write(ost, &ost->enc_stats_post, NULL, pkt,
                            e->packets_encoded);

        if (debug_ts) {
            av_log(e, AV_LOG_INFO, "encoder -> type:%s "
                   "pkt_pts:%s pkt_pts_time:%s pkt_dts:%s pkt_dts_time:%s "
                   "duration:%s duration_time:%s\n",
                   type_desc,
                   av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &enc->time_base),
                   av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &enc->time_base),
                   av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, &enc->time_base));
        }

        e->data_size += pkt->size;

        e->packets_encoded++;

        ret = sch_enc_send(e->sch, e->sch_idx, pkt);
        if (ret < 0) {
            av_packet_unref(pkt);
            return ret;
        }
    }

    av_assert0(0);
}

static enum AVPictureType forced_kf_apply(void *logctx, KeyframeForceCtx *kf,
                                          const AVFrame *frame)
{
    double pts_time;

    if (kf->ref_pts == AV_NOPTS_VALUE)
        kf->ref_pts = frame->pts;

    pts_time = (frame->pts - kf->ref_pts) * av_q2d(frame->time_base);
    if (kf->index < kf->nb_pts &&
        av_compare_ts(frame->pts, frame->time_base, kf->pts[kf->index], AV_TIME_BASE_Q) >= 0) {
        kf->index++;
        goto force_keyframe;
    } else if (kf->pexpr) {
        double res;
        kf->expr_const_values[FKF_T] = pts_time;
        res = av_expr_eval(kf->pexpr,
                           kf->expr_const_values, NULL);
        av_log(logctx, AV_LOG_TRACE,
               "force_key_frame: n:%f n_forced:%f prev_forced_n:%f t:%f prev_forced_t:%f -> res:%f\n",
               kf->expr_const_values[FKF_N],
               kf->expr_const_values[FKF_N_FORCED],
               kf->expr_const_values[FKF_PREV_FORCED_N],
               kf->expr_const_values[FKF_T],
               kf->expr_const_values[FKF_PREV_FORCED_T],
               res);

        kf->expr_const_values[FKF_N] += 1;

        if (res) {
            kf->expr_const_values[FKF_PREV_FORCED_N] = kf->expr_const_values[FKF_N] - 1;
            kf->expr_const_values[FKF_PREV_FORCED_T] = kf->expr_const_values[FKF_T];
            kf->expr_const_values[FKF_N_FORCED]     += 1;
            goto force_keyframe;
        }
    } else if (kf->type == KF_FORCE_SOURCE && (frame->flags & AV_FRAME_FLAG_KEY)) {
        goto force_keyframe;
    }

    return AV_PICTURE_TYPE_NONE;

force_keyframe:
    av_log(logctx, AV_LOG_DEBUG, "Forced keyframe at time %f\n", pts_time);
    return AV_PICTURE_TYPE_I;
}

static int frame_encode(OutputStream *ost, AVFrame *frame, AVPacket *pkt)
{
    Encoder *e = ost->enc;
    OutputFile *of = ost->file;
    enum AVMediaType type = ost->type;

    if (type == AVMEDIA_TYPE_SUBTITLE) {
        const AVSubtitle *subtitle = frame && frame->buf[0] ?
                                     (AVSubtitle*)frame->buf[0]->data : NULL;

        // no flushing for subtitles
        return subtitle && subtitle->num_rects ?
               do_subtitle_out(of, ost, subtitle, pkt) : 0;
    }

    if (frame) {
        if (!check_recording_time(ost, frame->pts, frame->time_base))
            return AVERROR_EOF;

        if (type == AVMEDIA_TYPE_VIDEO) {
            frame->quality   = ost->enc_ctx->global_quality;
            frame->pict_type = forced_kf_apply(e, &ost->kf, frame);

#if FFMPEG_OPT_TOP
            if (ost->top_field_first >= 0) {
                frame->flags &= ~AV_FRAME_FLAG_TOP_FIELD_FIRST;
                frame->flags |= AV_FRAME_FLAG_TOP_FIELD_FIRST * (!!ost->top_field_first);
            }
#endif
        } else {
            if (!(ost->enc_ctx->codec->capabilities & AV_CODEC_CAP_PARAM_CHANGE) &&
                ost->enc_ctx->ch_layout.nb_channels != frame->ch_layout.nb_channels) {
                av_log(e, AV_LOG_ERROR,
                       "Audio channel count changed and encoder does not support parameter changes\n");
                return 0;
            }
        }
    }

    return encode_frame(of, ost, frame, pkt);
}

static void enc_thread_set_name(const OutputStream *ost)
{
    char name[16];
    snprintf(name, sizeof(name), "enc%d:%d:%s", ost->file->index, ost->index,
             ost->enc_ctx->codec->name);
    ff_thread_setname(name);
}

static void enc_thread_uninit(EncoderThread *et)
{
    av_packet_free(&et->pkt);
    av_frame_free(&et->frame);

    memset(et, 0, sizeof(*et));
}

static int enc_thread_init(EncoderThread *et)
{
    memset(et, 0, sizeof(*et));

    et->frame = av_frame_alloc();
    if (!et->frame)
        goto fail;

    et->pkt = av_packet_alloc();
    if (!et->pkt)
        goto fail;

    return 0;

fail:
    enc_thread_uninit(et);
    return AVERROR(ENOMEM);
}

int encoder_thread(void *arg)
{
    OutputStream *ost = arg;
    Encoder        *e = ost->enc;
    EncoderThread et;
    int ret = 0, input_status = 0;
    int name_set = 0;

    ret = enc_thread_init(&et);
    if (ret < 0)
        goto finish;

    /* Open the subtitle encoders immediately. AVFrame-based encoders
     * are opened through a callback from the scheduler once they get
     * their first frame
     *
     * N.B.: because the callback is called from a different thread,
     * enc_ctx MUST NOT be accessed before sch_enc_receive() returns
     * for the first time for audio/video. */
    if (ost->type != AVMEDIA_TYPE_VIDEO && ost->type != AVMEDIA_TYPE_AUDIO) {
        ret = enc_open(ost, NULL);
        if (ret < 0)
            goto finish;
    }

    while (!input_status) {
        input_status = sch_enc_receive(e->sch, e->sch_idx, et.frame);
        if (input_status < 0) {
            if (input_status == AVERROR_EOF) {
                av_log(e, AV_LOG_VERBOSE, "Encoder thread received EOF\n");
                if (e->opened)
                    break;

                av_log(e, AV_LOG_ERROR, "Could not open encoder before EOF\n");
                ret = AVERROR(EINVAL);
            } else {
                av_log(e, AV_LOG_ERROR, "Error receiving a frame for encoding: %s\n",
                       av_err2str(ret));
                ret = input_status;
            }
            goto finish;
        }

        if (!name_set) {
            enc_thread_set_name(ost);
            name_set = 1;
        }

        ret = frame_encode(ost, et.frame, et.pkt);

        av_packet_unref(et.pkt);
        av_frame_unref(et.frame);

        if (ret < 0) {
            if (ret == AVERROR_EOF)
                av_log(e, AV_LOG_VERBOSE, "Encoder returned EOF, finishing\n");
            else
                av_log(e, AV_LOG_ERROR, "Error encoding a frame: %s\n",
                       av_err2str(ret));
            break;
        }
    }

    // flush the encoder
    if (ret == 0 || ret == AVERROR_EOF) {
        ret = frame_encode(ost, NULL, et.pkt);
        if (ret < 0 && ret != AVERROR_EOF)
            av_log(e, AV_LOG_ERROR, "Error flushing encoder: %s\n",
                   av_err2str(ret));
    }

    // EOF is normal thread termination
    if (ret == AVERROR_EOF)
        ret = 0;

finish:
    enc_thread_uninit(&et);

    return ret;
}

int enc_loopback(Encoder *enc)
{
    enc->attach_par = 1;
    return enc->sch_idx;
}