FFmpeg/libavcodec/encode.c

/*
 * generic encoding-related code
 *
 * 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 "libavutil/attributes.h"
#include "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavutil/emms.h"
#include "libavutil/frame.h"
#include "libavutil/imgutils.h"
#include "libavutil/internal.h"
#include "libavutil/mem.h"
#include "libavutil/pixdesc.h"
#include "libavutil/samplefmt.h"

#include "avcodec.h"
#include "avcodec_internal.h"
#include "codec_desc.h"
#include "codec_internal.h"
#include "encode.h"
#include "frame_thread_encoder.h"
#include "internal.h"

typedef struct EncodeContext {
    AVCodecInternal avci;

    /**
     * This is set to AV_PKT_FLAG_KEY for encoders that encode intra-only
     * formats (i.e. whose codec descriptor has AV_CODEC_PROP_INTRA_ONLY set).
     * This is used to set said flag generically for said encoders.
     */
    int intra_only_flag;

    /**
     * An audio frame with less than required samples has been submitted (and
     * potentially padded with silence). Reject all subsequent frames.
     */
    int last_audio_frame;
} EncodeContext;

static EncodeContext *encode_ctx(AVCodecInternal *avci)
{
    return (EncodeContext*)avci;
}

int ff_alloc_packet(AVCodecContext *avctx, AVPacket *avpkt, int64_t size)
{
    if (size < 0 || size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE) {
        av_log(avctx, AV_LOG_ERROR, "Invalid minimum required packet size %"PRId64" (max allowed is %d)\n",
               size, INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE);
        return AVERROR(EINVAL);
    }

    av_assert0(!avpkt->data);

    av_fast_padded_malloc(&avctx->internal->byte_buffer,
                          &avctx->internal->byte_buffer_size, size);
    avpkt->data = avctx->internal->byte_buffer;
    if (!avpkt->data) {
        av_log(avctx, AV_LOG_ERROR, "Failed to allocate packet of size %"PRId64"\n", size);
        return AVERROR(ENOMEM);
    }
    avpkt->size = size;

    return 0;
}

int avcodec_default_get_encode_buffer(AVCodecContext *avctx, AVPacket *avpkt, int flags)
{
    int ret;

    if (avpkt->size < 0 || avpkt->size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE)
        return AVERROR(EINVAL);

    if (avpkt->data || avpkt->buf) {
        av_log(avctx, AV_LOG_ERROR, "avpkt->{data,buf} != NULL in avcodec_default_get_encode_buffer()\n");
        return AVERROR(EINVAL);
    }

    ret = av_buffer_realloc(&avpkt->buf, avpkt->size + AV_INPUT_BUFFER_PADDING_SIZE);
    if (ret < 0) {
        av_log(avctx, AV_LOG_ERROR, "Failed to allocate packet of size %d\n", avpkt->size);
        return ret;
    }
    avpkt->data = avpkt->buf->data;

    return 0;
}

int ff_get_encode_buffer(AVCodecContext *avctx, AVPacket *avpkt, int64_t size, int flags)
{
    int ret;

    if (size < 0 || size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE)
        return AVERROR(EINVAL);

    av_assert0(!avpkt->data && !avpkt->buf);

    avpkt->size = size;
    ret = avctx->get_encode_buffer(avctx, avpkt, flags);
    if (ret < 0)
        goto fail;

    if (!avpkt->data || !avpkt->buf) {
        av_log(avctx, AV_LOG_ERROR, "No buffer returned by get_encode_buffer()\n");
        ret = AVERROR(EINVAL);
        goto fail;
    }
    memset(avpkt->data + avpkt->size, 0, AV_INPUT_BUFFER_PADDING_SIZE);

    ret = 0;
fail:
    if (ret < 0) {
        av_log(avctx, AV_LOG_ERROR, "get_encode_buffer() failed\n");
        av_packet_unref(avpkt);
    }

    return ret;
}

static int encode_make_refcounted(AVCodecContext *avctx, AVPacket *avpkt)
{
    uint8_t *data = avpkt->data;
    int ret;

    if (avpkt->buf)
        return 0;

    avpkt->data = NULL;
    ret = ff_get_encode_buffer(avctx, avpkt, avpkt->size, 0);
    if (ret < 0)
        return ret;
    memcpy(avpkt->data, data, avpkt->size);

    return 0;
}

/**
 * Pad last frame with silence.
 */
static int pad_last_frame(AVCodecContext *s, AVFrame *frame, const AVFrame *src, int out_samples)
{
    int ret;

    frame->format         = src->format;
    frame->nb_samples     = out_samples;
    ret = av_channel_layout_copy(&frame->ch_layout, &s->ch_layout);
    if (ret < 0)
        goto fail;
    ret = av_frame_get_buffer(frame, 0);
    if (ret < 0)
        goto fail;

    ret = av_frame_copy_props(frame, src);
    if (ret < 0)
        goto fail;

    if ((ret = av_samples_copy(frame->extended_data, src->extended_data, 0, 0,
                               src->nb_samples, s->ch_layout.nb_channels,
                               s->sample_fmt)) < 0)
        goto fail;
    if ((ret = av_samples_set_silence(frame->extended_data, src->nb_samples,
                                      frame->nb_samples - src->nb_samples,
                                      s->ch_layout.nb_channels, s->sample_fmt)) < 0)
        goto fail;

    return 0;

fail:
    av_frame_unref(frame);
    encode_ctx(s->internal)->last_audio_frame = 0;
    return ret;
}

int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
                            const AVSubtitle *sub)
{
    int ret;
    if (sub->start_display_time) {
        av_log(avctx, AV_LOG_ERROR, "start_display_time must be 0.\n");
        return -1;
    }

    ret = ffcodec(avctx->codec)->cb.encode_sub(avctx, buf, buf_size, sub);
    avctx->frame_num++;
    return ret;
}

int ff_encode_get_frame(AVCodecContext *avctx, AVFrame *frame)
{
    AVCodecInternal *avci = avctx->internal;

    if (avci->draining)
        return AVERROR_EOF;

    if (!avci->buffer_frame->buf[0])
        return AVERROR(EAGAIN);

    av_frame_move_ref(frame, avci->buffer_frame);

#if FF_API_FRAME_KEY
FF_DISABLE_DEPRECATION_WARNINGS
    if (frame->key_frame)
        frame->flags |= AV_FRAME_FLAG_KEY;
FF_ENABLE_DEPRECATION_WARNINGS
#endif
#if FF_API_INTERLACED_FRAME
FF_DISABLE_DEPRECATION_WARNINGS
    if (frame->interlaced_frame)
        frame->flags |= AV_FRAME_FLAG_INTERLACED;
    if (frame->top_field_first)
        frame->flags |= AV_FRAME_FLAG_TOP_FIELD_FIRST;
FF_ENABLE_DEPRECATION_WARNINGS
#endif

    return 0;
}

int ff_encode_reordered_opaque(AVCodecContext *avctx,
                               AVPacket *pkt, const AVFrame *frame)
{
    if (avctx->flags & AV_CODEC_FLAG_COPY_OPAQUE) {
        int ret = av_buffer_replace(&pkt->opaque_ref, frame->opaque_ref);
        if (ret < 0)
            return ret;
        pkt->opaque = frame->opaque;
    }

    return 0;
}

int ff_encode_encode_cb(AVCodecContext *avctx, AVPacket *avpkt,
                        AVFrame *frame, int *got_packet)
{
    const FFCodec *const codec = ffcodec(avctx->codec);
    int ret;

    ret = codec->cb.encode(avctx, avpkt, frame, got_packet);
    emms_c();
    av_assert0(ret <= 0);

    if (!ret && *got_packet) {
        if (avpkt->data) {
            ret = encode_make_refcounted(avctx, avpkt);
            if (ret < 0)
                goto unref;
            // Date returned by encoders must always be ref-counted
            av_assert0(avpkt->buf);
        }

        // set the timestamps for the simple no-delay case
        // encoders with delay have to set the timestamps themselves
        if (!(avctx->codec->capabilities & AV_CODEC_CAP_DELAY) ||
            (frame && (codec->caps_internal & FF_CODEC_CAP_EOF_FLUSH))) {
            if (avpkt->pts == AV_NOPTS_VALUE)
                avpkt->pts = frame->pts;

            if (!avpkt->duration) {
                if (frame->duration)
                    avpkt->duration = frame->duration;
                else if (avctx->codec->type == AVMEDIA_TYPE_AUDIO) {
                    avpkt->duration = ff_samples_to_time_base(avctx,
                                                              frame->nb_samples);
                }
            }

            ret = ff_encode_reordered_opaque(avctx, avpkt, frame);
            if (ret < 0)
                goto unref;
        }

        // dts equals pts unless there is reordering
        // there can be no reordering if there is no encoder delay
        if (!(avctx->codec_descriptor->props & AV_CODEC_PROP_REORDER) ||
            !(avctx->codec->capabilities & AV_CODEC_CAP_DELAY)        ||
            (codec->caps_internal & FF_CODEC_CAP_EOF_FLUSH))
            avpkt->dts = avpkt->pts;
    } else {
unref:
        av_packet_unref(avpkt);
    }

    if (frame)
        av_frame_unref(frame);

    return ret;
}

static int encode_simple_internal(AVCodecContext *avctx, AVPacket *avpkt)
{
    AVCodecInternal   *avci = avctx->internal;
    AVFrame          *frame = avci->in_frame;
    const FFCodec *const codec = ffcodec(avctx->codec);
    int got_packet;
    int ret;

    if (avci->draining_done)
        return AVERROR_EOF;

    if (!frame->buf[0] && !avci->draining) {
        av_frame_unref(frame);
        ret = ff_encode_get_frame(avctx, frame);
        if (ret < 0 && ret != AVERROR_EOF)
            return ret;
    }

    if (!frame->buf[0]) {
        if (!(avctx->codec->capabilities & AV_CODEC_CAP_DELAY ||
              avci->frame_thread_encoder))
            return AVERROR_EOF;

        // Flushing is signaled with a NULL frame
        frame = NULL;
    }

    got_packet = 0;

    av_assert0(codec->cb_type == FF_CODEC_CB_TYPE_ENCODE);

    if (CONFIG_FRAME_THREAD_ENCODER && avci->frame_thread_encoder)
        /* This will unref frame. */
        ret = ff_thread_video_encode_frame(avctx, avpkt, frame, &got_packet);
    else {
        ret = ff_encode_encode_cb(avctx, avpkt, frame, &got_packet);
    }

    if (avci->draining && !got_packet)
        avci->draining_done = 1;

    return ret;
}

static int encode_simple_receive_packet(AVCodecContext *avctx, AVPacket *avpkt)
{
    int ret;

    while (!avpkt->data && !avpkt->side_data) {
        ret = encode_simple_internal(avctx, avpkt);
        if (ret < 0)
            return ret;
    }

    return 0;
}

static int encode_receive_packet_internal(AVCodecContext *avctx, AVPacket *avpkt)
{
    AVCodecInternal *avci = avctx->internal;
    int ret;

    if (avci->draining_done)
        return AVERROR_EOF;

    av_assert0(!avpkt->data && !avpkt->side_data);

    if (avctx->codec->type == AVMEDIA_TYPE_VIDEO) {
        if ((avctx->flags & AV_CODEC_FLAG_PASS1) && avctx->stats_out)
            avctx->stats_out[0] = '\0';
        if (av_image_check_size2(avctx->width, avctx->height, avctx->max_pixels, AV_PIX_FMT_NONE, 0, avctx))
            return AVERROR(EINVAL);
    }

    if (ffcodec(avctx->codec)->cb_type == FF_CODEC_CB_TYPE_RECEIVE_PACKET) {
        ret = ffcodec(avctx->codec)->cb.receive_packet(avctx, avpkt);
        if (ret < 0)
            av_packet_unref(avpkt);
        else
            // Encoders must always return ref-counted buffers.
            // Side-data only packets have no data and can be not ref-counted.
            av_assert0(!avpkt->data || avpkt->buf);
    } else
        ret = encode_simple_receive_packet(avctx, avpkt);
    if (ret >= 0)
        avpkt->flags |= encode_ctx(avci)->intra_only_flag;

    if (ret == AVERROR_EOF)
        avci->draining_done = 1;

    return ret;
}

#if CONFIG_LCMS2
static int encode_generate_icc_profile(AVCodecContext *avctx, AVFrame *frame)
{
    enum AVColorTransferCharacteristic trc = frame->color_trc;
    enum AVColorPrimaries prim = frame->color_primaries;
    const FFCodec *const codec = ffcodec(avctx->codec);
    AVCodecInternal *avci = avctx->internal;
    cmsHPROFILE profile;
    int ret;

    /* don't generate ICC profiles if disabled or unsupported */
    if (!(avctx->flags2 & AV_CODEC_FLAG2_ICC_PROFILES))
        return 0;
    if (!(codec->caps_internal & FF_CODEC_CAP_ICC_PROFILES))
        return 0;

    if (trc == AVCOL_TRC_UNSPECIFIED)
        trc = avctx->color_trc;
    if (prim == AVCOL_PRI_UNSPECIFIED)
        prim = avctx->color_primaries;
    if (trc == AVCOL_TRC_UNSPECIFIED || prim == AVCOL_PRI_UNSPECIFIED)
        return 0; /* can't generate ICC profile with missing csp tags */

    if (av_frame_get_side_data(frame, AV_FRAME_DATA_ICC_PROFILE))
        return 0; /* don't overwrite existing ICC profile */

    if (!avci->icc.avctx) {
        ret = ff_icc_context_init(&avci->icc, avctx);
        if (ret < 0)
            return ret;
    }

    ret = ff_icc_profile_generate(&avci->icc, prim, trc, &profile);
    if (ret < 0)
        return ret;

    ret = ff_icc_profile_attach(&avci->icc, profile, frame);
    cmsCloseProfile(profile);
    return ret;
}
#else /* !CONFIG_LCMS2 */
static int encode_generate_icc_profile(av_unused AVCodecContext *c, av_unused AVFrame *f)
{
    return 0;
}
#endif

static int encode_send_frame_internal(AVCodecContext *avctx, const AVFrame *src)
{
    AVCodecInternal *avci = avctx->internal;
    EncodeContext     *ec = encode_ctx(avci);
    AVFrame *dst = avci->buffer_frame;
    int ret;

    if (avctx->codec->type == AVMEDIA_TYPE_AUDIO) {
        /* extract audio service type metadata */
        AVFrameSideData *sd = av_frame_get_side_data(src, AV_FRAME_DATA_AUDIO_SERVICE_TYPE);
        if (sd && sd->size >= sizeof(enum AVAudioServiceType))
            avctx->audio_service_type = *(enum AVAudioServiceType*)sd->data;

        /* check for valid frame size */
        if (!(avctx->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE)) {
            /* if we already got an undersized frame, that must have been the last */
            if (ec->last_audio_frame) {
                av_log(avctx, AV_LOG_ERROR, "frame_size (%d) was not respected for a non-last frame\n", avctx->frame_size);
                return AVERROR(EINVAL);
            }
            if (src->nb_samples > avctx->frame_size) {
                av_log(avctx, AV_LOG_ERROR, "nb_samples (%d) > frame_size (%d)\n", src->nb_samples, avctx->frame_size);
                return AVERROR(EINVAL);
            }
            if (src->nb_samples < avctx->frame_size) {
                ec->last_audio_frame = 1;
                if (!(avctx->codec->capabilities & AV_CODEC_CAP_SMALL_LAST_FRAME)) {
                    int pad_samples = avci->pad_samples ? avci->pad_samples : avctx->frame_size;
                    int out_samples = (src->nb_samples + pad_samples - 1) / pad_samples * pad_samples;

                    if (out_samples != src->nb_samples) {
                        ret = pad_last_frame(avctx, dst, src, out_samples);
                        if (ret < 0)
                            return ret;
                        goto finish;
                    }
                }
            }
        }
    }

    ret = av_frame_ref(dst, src);
    if (ret < 0)
        return ret;

finish:

    if (avctx->codec->type == AVMEDIA_TYPE_VIDEO) {
        ret = encode_generate_icc_profile(avctx, dst);
        if (ret < 0)
            return ret;
    }

    // unset frame duration unless AV_CODEC_FLAG_FRAME_DURATION is set,
    // since otherwise we cannot be sure that whatever value it has is in the
    // right timebase, so we would produce an incorrect value, which is worse
    // than none at all
    if (!(avctx->flags & AV_CODEC_FLAG_FRAME_DURATION))
        dst->duration = 0;

    return 0;
}

int attribute_align_arg avcodec_send_frame(AVCodecContext *avctx, const AVFrame *frame)
{
    AVCodecInternal *avci = avctx->internal;
    int ret;

    if (!avcodec_is_open(avctx) || !av_codec_is_encoder(avctx->codec))
        return AVERROR(EINVAL);

    if (avci->draining)
        return AVERROR_EOF;

    if (avci->buffer_frame->buf[0])
        return AVERROR(EAGAIN);

    if (!frame) {
        avci->draining = 1;
    } else {
        ret = encode_send_frame_internal(avctx, frame);
        if (ret < 0)
            return ret;
    }

    if (!avci->buffer_pkt->data && !avci->buffer_pkt->side_data) {
        ret = encode_receive_packet_internal(avctx, avci->buffer_pkt);
        if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF)
            return ret;
    }

    avctx->frame_num++;

    return 0;
}

int attribute_align_arg avcodec_receive_packet(AVCodecContext *avctx, AVPacket *avpkt)
{
    AVCodecInternal *avci = avctx->internal;
    int ret;

    av_packet_unref(avpkt);

    if (!avcodec_is_open(avctx) || !av_codec_is_encoder(avctx->codec))
        return AVERROR(EINVAL);

    if (avci->buffer_pkt->data || avci->buffer_pkt->side_data) {
        av_packet_move_ref(avpkt, avci->buffer_pkt);
    } else {
        ret = encode_receive_packet_internal(avctx, avpkt);
        if (ret < 0)
            return ret;
    }

    return 0;
}

static int encode_preinit_video(AVCodecContext *avctx)
{
    const AVCodec *c = avctx->codec;
    const AVPixFmtDescriptor *pixdesc = av_pix_fmt_desc_get(avctx->pix_fmt);
    const enum AVPixelFormat *pix_fmts;
    int ret, i, num_pix_fmts;

    if (!av_get_pix_fmt_name(avctx->pix_fmt)) {
        av_log(avctx, AV_LOG_ERROR, "Invalid video pixel format: %d\n",
               avctx->pix_fmt);
        return AVERROR(EINVAL);
    }

    ret = avcodec_get_supported_config(avctx, NULL, AV_CODEC_CONFIG_PIX_FORMAT,
                                       0, (const void **) &pix_fmts, &num_pix_fmts);
    if (ret < 0)
        return ret;

    if (pix_fmts) {
        for (i = 0; i < num_pix_fmts; i++)
            if (avctx->pix_fmt == pix_fmts[i])
                break;
        if (i == num_pix_fmts) {
            av_log(avctx, AV_LOG_ERROR,
                   "Specified pixel format %s is not supported by the %s encoder.\n",
                   av_get_pix_fmt_name(avctx->pix_fmt), c->name);

            av_log(avctx, AV_LOG_ERROR, "Supported pixel formats:\n");
            for (int p = 0; pix_fmts[p] != AV_PIX_FMT_NONE; p++) {
                av_log(avctx, AV_LOG_ERROR, "  %s\n",
                       av_get_pix_fmt_name(pix_fmts[p]));
            }

            return AVERROR(EINVAL);
        }
        if (pix_fmts[i] == AV_PIX_FMT_YUVJ420P ||
            pix_fmts[i] == AV_PIX_FMT_YUVJ411P ||
            pix_fmts[i] == AV_PIX_FMT_YUVJ422P ||
            pix_fmts[i] == AV_PIX_FMT_YUVJ440P ||
            pix_fmts[i] == AV_PIX_FMT_YUVJ444P)
            avctx->color_range = AVCOL_RANGE_JPEG;
    }

    if (    avctx->bits_per_raw_sample < 0
        || (avctx->bits_per_raw_sample > 8 && pixdesc->comp[0].depth <= 8)) {
        av_log(avctx, AV_LOG_WARNING, "Specified bit depth %d not possible with the specified pixel formats depth %d\n",
            avctx->bits_per_raw_sample, pixdesc->comp[0].depth);
        avctx->bits_per_raw_sample = pixdesc->comp[0].depth;
    }
    if (avctx->width <= 0 || avctx->height <= 0) {
        av_log(avctx, AV_LOG_ERROR, "dimensions not set\n");
        return AVERROR(EINVAL);
    }

#if FF_API_TICKS_PER_FRAME
FF_DISABLE_DEPRECATION_WARNINGS
    if (avctx->ticks_per_frame && avctx->time_base.num &&
        avctx->ticks_per_frame > INT_MAX / avctx->time_base.num) {
        av_log(avctx, AV_LOG_ERROR,
               "ticks_per_frame %d too large for the timebase %d/%d.",
               avctx->ticks_per_frame,
               avctx->time_base.num,
               avctx->time_base.den);
        return AVERROR(EINVAL);
    }
FF_ENABLE_DEPRECATION_WARNINGS
#endif

    if (avctx->hw_frames_ctx) {
        AVHWFramesContext *frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data;
        if (frames_ctx->format != avctx->pix_fmt) {
            av_log(avctx, AV_LOG_ERROR,
                   "Mismatching AVCodecContext.pix_fmt and AVHWFramesContext.format\n");
            return AVERROR(EINVAL);
        }
        if (avctx->sw_pix_fmt != AV_PIX_FMT_NONE &&
            avctx->sw_pix_fmt != frames_ctx->sw_format) {
            av_log(avctx, AV_LOG_ERROR,
                   "Mismatching AVCodecContext.sw_pix_fmt (%s) "
                   "and AVHWFramesContext.sw_format (%s)\n",
                   av_get_pix_fmt_name(avctx->sw_pix_fmt),
                   av_get_pix_fmt_name(frames_ctx->sw_format));
            return AVERROR(EINVAL);
        }
        avctx->sw_pix_fmt = frames_ctx->sw_format;
    }

    return 0;
}

static int encode_preinit_audio(AVCodecContext *avctx)
{
    const AVCodec *c = avctx->codec;
    const enum AVSampleFormat *sample_fmts;
    const int *supported_samplerates;
    const AVChannelLayout *ch_layouts;
    int ret, i, num_sample_fmts, num_samplerates, num_ch_layouts;

    if (!av_get_sample_fmt_name(avctx->sample_fmt)) {
        av_log(avctx, AV_LOG_ERROR, "Invalid audio sample format: %d\n",
               avctx->sample_fmt);
        return AVERROR(EINVAL);
    }
    if (avctx->sample_rate <= 0) {
        av_log(avctx, AV_LOG_ERROR, "Invalid audio sample rate: %d\n",
               avctx->sample_rate);
        return AVERROR(EINVAL);
    }

    ret = avcodec_get_supported_config(avctx, NULL, AV_CODEC_CONFIG_SAMPLE_FORMAT,
                                       0, (const void **) &sample_fmts,
                                       &num_sample_fmts);
    if (ret < 0)
        return ret;
    if (sample_fmts) {
        for (i = 0; i < num_sample_fmts; i++) {
            if (avctx->sample_fmt == sample_fmts[i])
                break;
            if (avctx->ch_layout.nb_channels == 1 &&
                av_get_planar_sample_fmt(avctx->sample_fmt) ==
                av_get_planar_sample_fmt(sample_fmts[i])) {
                avctx->sample_fmt = sample_fmts[i];
                break;
            }
        }
        if (i == num_sample_fmts) {
            av_log(avctx, AV_LOG_ERROR,
                   "Specified sample format %s is not supported by the %s encoder\n",
                   av_get_sample_fmt_name(avctx->sample_fmt), c->name);

            av_log(avctx, AV_LOG_ERROR, "Supported sample formats:\n");
            for (int p = 0; sample_fmts[p] != AV_SAMPLE_FMT_NONE; p++) {
                av_log(avctx, AV_LOG_ERROR, "  %s\n",
                       av_get_sample_fmt_name(sample_fmts[p]));
            }

            return AVERROR(EINVAL);
        }
    }

    ret = avcodec_get_supported_config(avctx, NULL, AV_CODEC_CONFIG_SAMPLE_RATE,
                                       0, (const void **) &supported_samplerates,
                                       &num_samplerates);
    if (ret < 0)
        return ret;
    if (supported_samplerates) {
        for (i = 0; i < num_samplerates; i++)
            if (avctx->sample_rate == supported_samplerates[i])
                break;
        if (i == num_samplerates) {
            av_log(avctx, AV_LOG_ERROR,
                   "Specified sample rate %d is not supported by the %s encoder\n",
                   avctx->sample_rate, c->name);

            av_log(avctx, AV_LOG_ERROR, "Supported sample rates:\n");
            for (int p = 0; supported_samplerates[p]; p++)
                av_log(avctx, AV_LOG_ERROR, "  %d\n", supported_samplerates[p]);

            return AVERROR(EINVAL);
        }
    }
    ret = avcodec_get_supported_config(avctx, NULL, AV_CODEC_CONFIG_CHANNEL_LAYOUT,
                                       0, (const void **) &ch_layouts, &num_ch_layouts);
    if (ret < 0)
        return ret;
    if (ch_layouts) {
        for (i = 0; i < num_ch_layouts; i++) {
            if (!av_channel_layout_compare(&avctx->ch_layout, &ch_layouts[i]))
                break;
        }
        if (i == num_ch_layouts) {
            char buf[512];
            int ret = av_channel_layout_describe(&avctx->ch_layout, buf, sizeof(buf));
            av_log(avctx, AV_LOG_ERROR,
                   "Specified channel layout '%s' is not supported by the %s encoder\n",
                   ret > 0 ? buf : "?", c->name);

            av_log(avctx, AV_LOG_ERROR, "Supported channel layouts:\n");
            for (int p = 0; ch_layouts[p].nb_channels; p++) {
                ret = av_channel_layout_describe(&ch_layouts[p], buf, sizeof(buf));
                av_log(avctx, AV_LOG_ERROR, "  %s\n", ret > 0 ? buf : "?");
            }
            return AVERROR(EINVAL);
        }
    }

    if (!avctx->bits_per_raw_sample)
        avctx->bits_per_raw_sample = av_get_exact_bits_per_sample(avctx->codec_id);
    if (!avctx->bits_per_raw_sample)
        avctx->bits_per_raw_sample = 8 * av_get_bytes_per_sample(avctx->sample_fmt);

    return 0;
}

int ff_encode_preinit(AVCodecContext *avctx)
{
    AVCodecInternal *avci = avctx->internal;
    EncodeContext     *ec = encode_ctx(avci);
    int ret = 0;

    if (avctx->time_base.num <= 0 || avctx->time_base.den <= 0) {
        av_log(avctx, AV_LOG_ERROR, "The encoder timebase is not set.\n");
        return AVERROR(EINVAL);
    }

    if (avctx->bit_rate < 0) {
        av_log(avctx, AV_LOG_ERROR, "The encoder bitrate is negative.\n");
        return AVERROR(EINVAL);
    }

    if (avctx->flags & AV_CODEC_FLAG_COPY_OPAQUE &&
        !(avctx->codec->capabilities & AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE)) {
        av_log(avctx, AV_LOG_ERROR, "The copy_opaque flag is set, but the "
               "encoder does not support it.\n");
        return AVERROR(EINVAL);
    }

    switch (avctx->codec_type) {
    case AVMEDIA_TYPE_VIDEO: ret = encode_preinit_video(avctx); break;
    case AVMEDIA_TYPE_AUDIO: ret = encode_preinit_audio(avctx); break;
    }
    if (ret < 0)
        return ret;

    if (   (avctx->codec_type == AVMEDIA_TYPE_VIDEO || avctx->codec_type == AVMEDIA_TYPE_AUDIO)
        && avctx->bit_rate>0 && avctx->bit_rate<1000) {
        av_log(avctx, AV_LOG_WARNING, "Bitrate %"PRId64" is extremely low, maybe you mean %"PRId64"k\n", avctx->bit_rate, avctx->bit_rate);
    }

    if (!avctx->rc_initial_buffer_occupancy)
        avctx->rc_initial_buffer_occupancy = avctx->rc_buffer_size * 3LL / 4;

    if (avctx->codec_descriptor->props & AV_CODEC_PROP_INTRA_ONLY)
        ec->intra_only_flag = AV_PKT_FLAG_KEY;

    if (ffcodec(avctx->codec)->cb_type == FF_CODEC_CB_TYPE_ENCODE) {
        avci->in_frame = av_frame_alloc();
        if (!avci->in_frame)
            return AVERROR(ENOMEM);
    }

    if ((avctx->flags & AV_CODEC_FLAG_RECON_FRAME)) {
        if (!(avctx->codec->capabilities & AV_CODEC_CAP_ENCODER_RECON_FRAME)) {
            av_log(avctx, AV_LOG_ERROR, "Reconstructed frame output requested "
                   "from an encoder not supporting it\n");
            return AVERROR(ENOSYS);
        }

        avci->recon_frame = av_frame_alloc();
        if (!avci->recon_frame)
            return AVERROR(ENOMEM);
    }

    for (int i = 0; ff_sd_global_map[i].packet < AV_PKT_DATA_NB; i++) {
        const enum AVPacketSideDataType type_packet = ff_sd_global_map[i].packet;
        const enum AVFrameSideDataType  type_frame  = ff_sd_global_map[i].frame;
        const AVFrameSideData *sd_frame;
        AVPacketSideData      *sd_packet;

        sd_frame = av_frame_side_data_get(avctx->decoded_side_data,
                                          avctx->nb_decoded_side_data,
                                          type_frame);
        if (!sd_frame ||
            av_packet_side_data_get(avctx->coded_side_data, avctx->nb_coded_side_data,
                                    type_packet))

            continue;

        sd_packet = av_packet_side_data_new(&avctx->coded_side_data, &avctx->nb_coded_side_data,
                                            type_packet, sd_frame->size, 0);
        if (!sd_packet)
            return AVERROR(ENOMEM);

        memcpy(sd_packet->data, sd_frame->data, sd_frame->size);
    }

    if (CONFIG_FRAME_THREAD_ENCODER) {
        ret = ff_frame_thread_encoder_init(avctx);
        if (ret < 0)
            return ret;
    }

    return 0;
}

int ff_encode_alloc_frame(AVCodecContext *avctx, AVFrame *frame)
{
    int ret;

    switch (avctx->codec->type) {
    case AVMEDIA_TYPE_VIDEO:
        frame->format = avctx->pix_fmt;
        if (frame->width <= 0 || frame->height <= 0) {
            frame->width  = FFMAX(avctx->width,  avctx->coded_width);
            frame->height = FFMAX(avctx->height, avctx->coded_height);
        }

        break;
    case AVMEDIA_TYPE_AUDIO:
        frame->sample_rate = avctx->sample_rate;
        frame->format      = avctx->sample_fmt;
        if (!frame->ch_layout.nb_channels) {
            ret = av_channel_layout_copy(&frame->ch_layout, &avctx->ch_layout);
            if (ret < 0)
                return ret;
        }
        break;
    }

    ret = avcodec_default_get_buffer2(avctx, frame, 0);
    if (ret < 0) {
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        av_frame_unref(frame);
        return ret;
    }

    return 0;
}

int ff_encode_receive_frame(AVCodecContext *avctx, AVFrame *frame)
{
    AVCodecInternal *avci = avctx->internal;

    if (!avci->recon_frame)
        return AVERROR(EINVAL);
    if (!avci->recon_frame->buf[0])
        return avci->draining_done ? AVERROR_EOF : AVERROR(EAGAIN);

    av_frame_move_ref(frame, avci->recon_frame);
    return 0;
}

void ff_encode_flush_buffers(AVCodecContext *avctx)
{
    AVCodecInternal *avci = avctx->internal;

    if (avci->in_frame)
        av_frame_unref(avci->in_frame);
    if (avci->recon_frame)
        av_frame_unref(avci->recon_frame);
}

AVCodecInternal *ff_encode_internal_alloc(void)
{
    return av_mallocz(sizeof(EncodeContext));
}

AVCPBProperties *ff_encode_add_cpb_side_data(AVCodecContext *avctx)
{
    AVPacketSideData *tmp;
    AVCPBProperties  *props;
    size_t size;
    int i;

    for (i = 0; i < avctx->nb_coded_side_data; i++)
        if (avctx->coded_side_data[i].type == AV_PKT_DATA_CPB_PROPERTIES)
            return (AVCPBProperties *)avctx->coded_side_data[i].data;

    props = av_cpb_properties_alloc(&size);
    if (!props)
        return NULL;

    tmp = av_realloc_array(avctx->coded_side_data, avctx->nb_coded_side_data + 1, sizeof(*tmp));
    if (!tmp) {
        av_freep(&props);
        return NULL;
    }

    avctx->coded_side_data = tmp;
    avctx->nb_coded_side_data++;

    avctx->coded_side_data[avctx->nb_coded_side_data - 1].type = AV_PKT_DATA_CPB_PROPERTIES;
    avctx->coded_side_data[avctx->nb_coded_side_data - 1].data = (uint8_t*)props;
    avctx->coded_side_data[avctx->nb_coded_side_data - 1].size = size;

    return props;
}