/*

 * This file is part of mpv.

 *

 * mpv 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.

 *

 * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.

 */

#include <assert.h>

#include <math.h>

#include <limits.h>

#include <libavutil/common.h>

#include <libavutil/log.h>

#include <libavutil/dict.h>

#include <libavutil/opt.h>

#include <libavutil/error.h>

#include <libavutil/cpu.h>

#include <libavcodec/avcodec.h>

#include <libavformat/avformat.h>

#include "config.h"

#include "audio/chmap_avchannel.h"

#include "common/common.h"

#include "common/msg.h"

#include "demux/packet.h"

#include "demux/stheader.h"

#include "misc/bstr.h"

#include "video/fmt-conversion.h"

#include "av_common.h"

#include "codecs.h"

enum AVMediaType mp_to_av_stream_type(int type)

{

    switch (type) {

    case STREAM_VIDEO: return AVMEDIA_TYPE_VIDEO;

    case STREAM_AUDIO: return AVMEDIA_TYPE_AUDIO;

    case STREAM_SUB:   return AVMEDIA_TYPE_SUBTITLE;

    default:           return AVMEDIA_TYPE_UNKNOWN;

    }

}

AVCodecParameters *mp_codec_params_to_av(const struct mp_codec_params *c)

{

    AVCodecParameters *avp = avcodec_parameters_alloc();

    if (!avp)

        return NULL;

    // If we have lavf demuxer params, they overwrite by definition any others.

    if (c->lav_codecpar) {

        if (avcodec_parameters_copy(avp, c->lav_codecpar) < 0)

            goto error;

        return avp;

    }

    avp->codec_type = mp_to_av_stream_type(c->type);

    avp->codec_id = mp_codec_to_av_codec_id(c->codec);

    avp->codec_tag = c->codec_tag;

    if (c->extradata_size) {

        uint8_t *extradata = c->extradata;

        int size = c->extradata_size;

        if (avp->codec_id == AV_CODEC_ID_FLAC) {

            // ffmpeg expects FLAC extradata to be just the STREAMINFO,

            // so grab only that (and assume it'll be the first block)

            if (size >= 8 && !memcmp(c->extradata, "fLaC", 4)) {

                extradata += 8;

                size = MPMIN(34, size - 8); // FLAC_STREAMINFO_SIZE

            }

        }

        avp->extradata = av_mallocz(size + AV_INPUT_BUFFER_PADDING_SIZE);

        if (!avp->extradata)

            goto error;

        avp->extradata_size = size;

        memcpy(avp->extradata, extradata, size);

    }

    avp->bits_per_coded_sample = c->bits_per_coded_sample;

    // Video only

    avp->width = c->disp_w;

    avp->height = c->disp_h;

    // Audio only

    avp->sample_rate = c->samplerate;

    avp->bit_rate = c->bitrate;

    avp->block_align = c->block_align;

    mp_chmap_to_av_layout(&avp->ch_layout, &c->channels);

    return avp;

error:

    avcodec_parameters_free(&avp);

    return NULL;

}

// Set avctx codec headers for decoding. Returns <0 on failure.

int mp_set_avctx_codec_headers(AVCodecContext *avctx, const struct mp_codec_params *c)

{

    enum AVMediaType codec_type = avctx->codec_type;

    enum AVCodecID codec_id = avctx->codec_id;

    AVCodecParameters *avp = mp_codec_params_to_av(c);

    if (!avp)

        return -1;

    int r = avcodec_parameters_to_context(avctx, avp) < 0 ? -1 : 0;

    avcodec_parameters_free(&avp);

    if (avctx->codec_type != AVMEDIA_TYPE_UNKNOWN)

        avctx->codec_type = codec_type;

    if (avctx->codec_id != AV_CODEC_ID_NONE)

        avctx->codec_id = codec_id;

    return r;

}

// Pick a "good" timebase, which will be used to convert double timestamps

// back to fractions for passing them through libavcodec.

AVRational mp_get_codec_timebase(const struct mp_codec_params *c)

{

    AVRational tb = {c->native_tb_num, c->native_tb_den};

    if (tb.num < 1 || tb.den < 1) {

        if (c->reliable_fps)

            tb = av_inv_q(av_d2q(c->fps, 1000000));

        if (tb.num < 1 || tb.den < 1)

            tb = AV_TIME_BASE_Q;

    }

    // If the timebase is too coarse, raise its precision, or small adjustments

    // to timestamps done between decoder and demuxer could be lost.

    int64_t den = tb.den;

    if (av_q2d(tb) > 0.001) {

        int64_t scaling_num = tb.num * INT64_C(1000);

        int64_t scaling_den = tb.den;

        den *= (scaling_num + scaling_den - 1) / scaling_den;

    }

    av_reduce(&tb.num, &tb.den, tb.num, den, INT_MAX);

    if (tb.num < 1 || tb.den < 1)

        tb = AV_TIME_BASE_Q;

    return tb;

}

static AVRational get_def_tb(AVRational *tb)

{

    return tb && tb->num > 0 && tb->den > 0 ? *tb : AV_TIME_BASE_Q;

}

// Convert the mpv style timestamp (seconds as double) to a libavcodec style

// timestamp (integer units in a given timebase).

int64_t mp_pts_to_av(double mp_pts, AVRational *tb)

{

    AVRational b = get_def_tb(tb);

    return mp_pts == MP_NOPTS_VALUE ? AV_NOPTS_VALUE : llrint(mp_pts / av_q2d(b));

}

// Inverse of mp_pts_to_av(). (The timebases must be exactly the same.)

double mp_pts_from_av(int64_t av_pts, AVRational *tb)

{

    AVRational b = get_def_tb(tb);

    return av_pts == AV_NOPTS_VALUE ? MP_NOPTS_VALUE : av_pts * av_q2d(b);

}

// Set dst from mpkt. Note that dst is not refcountable.

// mpkt can be NULL to generate empty packets (used to flush delayed data).

// Sets pts/dts using mp_pts_to_av(ts, tb). (Be aware of the implications.)

// Set duration field only if tb is set.

void mp_set_av_packet(AVPacket *dst, struct demux_packet *mpkt, AVRational *tb)

{

    dst->side_data = NULL;

    dst->side_data_elems = 0;

    dst->buf = NULL;

    av_packet_unref(dst);

    dst->data = mpkt ? mpkt->buffer : NULL;

    dst->size = mpkt ? mpkt->len : 0;

    /* Some codecs (ZeroCodec, some cases of PNG) may want keyframe info

     * from demuxer. */

    if (mpkt && mpkt->keyframe)

        dst->flags |= AV_PKT_FLAG_KEY;

    if (mpkt && mpkt->avpacket) {

        dst->side_data = mpkt->avpacket->side_data;

        dst->side_data_elems = mpkt->avpacket->side_data_elems;

        if (dst->data == mpkt->avpacket->data)

            dst->buf = mpkt->avpacket->buf;

        dst->flags |= mpkt->avpacket->flags;

    }

    if (mpkt && tb && tb->num > 0 && tb->den > 0)

        dst->duration = mpkt->duration / av_q2d(*tb);

    dst->pts = mp_pts_to_av(mpkt ? mpkt->pts : MP_NOPTS_VALUE, tb);

    dst->dts = mp_pts_to_av(mpkt ? mpkt->dts : MP_NOPTS_VALUE, tb);

}

void mp_set_avcodec_threads(struct mp_log *l, AVCodecContext *avctx, int threads)

{

    if (threads == 0) {

        threads = av_cpu_count();

        if (threads < 1) {

            mp_warn(l, "Could not determine thread count to use, defaulting to 1.\n");

            threads = 1;

        } else {

            mp_verbose(l, "Detected %d logical cores.\n", threads);

            if (threads > 1)

                threads += 1; // extra thread for better load balancing

        }

        // Apparently some libavcodec versions have or had trouble with more

        // than 16 threads, and/or print a warning when using > 16.

        threads = MPMIN(threads, 16);

    }

    mp_verbose(l, "Requesting %d threads for decoding.\n", threads);

    avctx->thread_count = threads;

}

static void add_codecs(struct mp_decoder_list *list, enum AVMediaType type,

                       bool decoders)

{

    void *iter = NULL;

    for (;;) {

        const AVCodec *cur = av_codec_iterate(&iter);

        if (!cur)

            break;

        if (av_codec_is_decoder(cur) == decoders &&

            (type == AVMEDIA_TYPE_UNKNOWN || cur->type == type))

        {

            mp_add_decoder(list, mp_codec_from_av_codec_id(cur->id),

                           cur->name, cur->long_name);

        }

    }

}

void mp_add_lavc_decoders(struct mp_decoder_list *list, enum AVMediaType type)

{

    add_codecs(list, type, true);

}

// (Abuses the decoder list data structures.)

void mp_add_lavc_encoders(struct mp_decoder_list *list)

{

    add_codecs(list, AVMEDIA_TYPE_UNKNOWN, false);

}

char **mp_get_lavf_demuxers(void)

{

    char **list = NULL;

    void *iter = NULL;

    int num = 0;

    for (;;) {

        const AVInputFormat *cur = av_demuxer_iterate(&iter);

        if (!cur)

            break;

        MP_TARRAY_APPEND(NULL, list, num, talloc_strdup(list, cur->name));

    }

    MP_TARRAY_APPEND(NULL, list, num, NULL);

    return list;

}

char **mp_get_lavf_protocols(void)

{

    char **list = NULL;

    int num = 0;

    void *opaque = NULL;

    const char *name;

    while ((name = avio_enum_protocols(&opaque, 0)))

        MP_TARRAY_APPEND(NULL, list, num, talloc_strdup(list, name));

    MP_TARRAY_APPEND(NULL, list, num, NULL);

    return list;

}

int mp_codec_to_av_codec_id(const char *codec)

{

    int id = AV_CODEC_ID_NONE;

    if (codec) {

        const AVCodecDescriptor *desc = avcodec_descriptor_get_by_name(codec);

        if (desc)

            id = desc->id;

        if (id == AV_CODEC_ID_NONE) {

            const AVCodec *avcodec = avcodec_find_decoder_by_name(codec);

            if (avcodec)

                id = avcodec->id;

        }

    }

    return id;

}

const char *mp_codec_from_av_codec_id(int codec_id)

{

    const char *name = NULL;

    const AVCodecDescriptor *desc = avcodec_descriptor_get(codec_id);

    if (desc)

        name = desc->name;

    if (!name) {

        const AVCodec *avcodec = avcodec_find_decoder(codec_id);

        if (avcodec)

            name = avcodec->name;

    }

    return name;

}

bool mp_codec_is_lossless(const char *codec)

{

    const AVCodecDescriptor *desc =

        avcodec_descriptor_get(mp_codec_to_av_codec_id(codec));

    return desc && (desc->props & AV_CODEC_PROP_LOSSLESS);

}

// kv is in the format as by OPT_KEYVALUELIST(): kv[0]=key0, kv[1]=val0, ...

// Copy them to the dict.

void mp_set_avdict(AVDictionary **dict, char **kv)

{

    for (int n = 0; kv && kv[n * 2]; n++)

        av_dict_set(dict, kv[n * 2 + 0], kv[n * 2 + 1], 0);

}

// For use with libav* APIs that take AVDictionaries of options.

// Print options remaining in the dict as unset.

void mp_avdict_print_unset(struct mp_log *log, int msgl, AVDictionary *dict)

{

    AVDictionaryEntry *t = NULL;

    while ((t = av_dict_get(dict, "", t, AV_DICT_IGNORE_SUFFIX)))

        mp_msg(log, msgl, "Could not set AVOption %s='%s'\n", t->key, t->value);

}

// If the name starts with "@", try to interpret it as a number, and set *name

// to the name of the n-th parameter.

static void resolve_positional_arg(void *avobj, char **name)

{

    if (!*name || (*name)[0] != '@' || !avobj)

        return;

    char *end = NULL;

    int pos = strtol(*name + 1, &end, 10);

    if (!end || *end || pos < 0)

        return;

    const AVOption *opt = NULL;

    int offset = -1;

    while (1) {

        opt = av_opt_next(avobj, opt);

        if (!opt)

            return;

        // This is what libavfilter's parser does to skip aliases.

        if (opt->offset != offset && opt->type != AV_OPT_TYPE_CONST)

            pos--;

        if (pos < 0) {

            *name = (char *)opt->name;

            return;

        }

        offset = opt->offset;

    }

}

// kv is in the format as by OPT_KEYVALUELIST(): kv[0]=key0, kv[1]=val0, ...

// Set these options on given avobj (using av_opt_set..., meaning avobj must

// point to a struct that has AVClass as first member).

// Options which fail to set (error or not found) are printed to log.

// Returns: >=0 success, <0 failed to set an option

int mp_set_avopts(struct mp_log *log, void *avobj, char **kv)

{

    return mp_set_avopts_pos(log, avobj, avobj, kv);

}

// Like mp_set_avopts(), but the posargs argument is used to resolve positional

// arguments. If posargs==NULL, positional args are disabled.

int mp_set_avopts_pos(struct mp_log *log, void *avobj, void *posargs, char **kv)

{

    int success = 0;

    for (int n = 0; kv && kv[n * 2]; n++) {

        char *k = kv[n * 2 + 0];

        char *v = kv[n * 2 + 1];

        resolve_positional_arg(posargs, &k);

        int r = av_opt_set(avobj, k, v, AV_OPT_SEARCH_CHILDREN);

        if (r == AVERROR_OPTION_NOT_FOUND) {

            mp_err(log, "AVOption '%s' not found.\n", k);

            success = -1;

        } else if (r < 0) {

            char errstr[80];

            av_strerror(r, errstr, sizeof(errstr));

            mp_err(log, "Could not set AVOption %s='%s' (%s)\n", k, v, errstr);

            success = -1;

        }

    }

    return success;

}

/**

 * Must be used to free an AVPacket that was used with mp_set_av_packet().

 *

 * We have a particular pattern where we "borrow" buffers and set them

 * into an AVPacket to pass data to ffmpeg without extra copies.

 * This applies to buf and side_data, so this function clears them before

 * freeing.

 */

void mp_free_av_packet(AVPacket **pkt)

{

    if (*pkt) {

        (*pkt)->side_data = NULL;

        (*pkt)->side_data_elems = 0;

        (*pkt)->buf = NULL;

    }

    av_packet_free(pkt);

}

void mp_codec_info_from_av(const AVCodecContext *avctx, struct mp_codec_params *c)

{

    c->codec_profile = av_get_profile_name(avctx->codec, avctx->profile);

    if (!c->codec_profile)

        c->codec_profile = avcodec_profile_name(avctx->codec_id, avctx->profile);

    c->codec = avctx->codec_descriptor->name;

    c->codec_desc = avctx->codec_descriptor->long_name;

    c->decoder = avctx->codec->name;

    c->decoder_desc = avctx->codec->long_name;

}

void mp_codec_info_from_avcodecpar(const AVCodecParameters *avcodecpar, struct mp_codec_params *c)

{

    const AVCodec *codec = avcodec_find_decoder(avcodecpar->codec_id);

    const AVCodecDescriptor *desc = avcodec_descriptor_get(avcodecpar->codec_id);

    c->codec = mp_codec_from_av_codec_id(avcodecpar->codec_id);

    if (desc)

        c->codec_desc = desc->long_name;

    if (codec) {

        c->decoder = codec->name;

        c->decoder_desc = codec->long_name;

        c->codec_profile = av_get_profile_name(codec, avcodecpar->profile);

    }

    if (!c->codec_profile)

        c->codec_profile = avcodec_profile_name(avcodecpar->codec_id, avcodecpar->profile);

}