libtwolame.c

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/*
 * Interface to libtwolame for mp2 encoding
 * Copyright (c) 2012 Paul B Mahol
 *
 * 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
 */

/**
 * @file
 * Interface to libtwolame for mp2 encoding.
 */

#include <twolame.h>

#include "libavutil/opt.h"
#include "avcodec.h"
#include "internal.h"
#include "mpegaudio.h"

typedef struct TWOLAMEContext {
    AVClass  *class;
    int      mode;
    int      psymodel;
    int      energy;
    int      error_protection;
    int      copyright;
    int      original;

    twolame_options *glopts;
    int64_t  next_pts;
} TWOLAMEContext;

static av_cold int twolame_encode_close(AVCodecContext *avctx)
{
    TWOLAMEContext *s = avctx->priv_data;
    twolame_close(&s->glopts);
    return 0;
}

static av_cold int twolame_encode_init(AVCodecContext *avctx)
{
    TWOLAMEContext *s = avctx->priv_data;
    int ret;

    avctx->frame_size = TWOLAME_SAMPLES_PER_FRAME;

    s->glopts = twolame_init();
    if (!s->glopts)
        return AVERROR(ENOMEM);

    twolame_set_verbosity(s->glopts, 0);
    twolame_set_mode(s->glopts, s->mode);
    twolame_set_psymodel(s->glopts, s->psymodel);
    twolame_set_energy_levels(s->glopts, s->energy);
    twolame_set_error_protection(s->glopts, s->error_protection);

    twolame_set_num_channels(s->glopts, avctx->channels);
    twolame_set_in_samplerate(s->glopts, avctx->sample_rate);
    twolame_set_out_samplerate(s->glopts, avctx->sample_rate);
    if (avctx->flags & CODEC_FLAG_QSCALE || !avctx->bit_rate) {
        twolame_set_VBR(s->glopts, TRUE);
        twolame_set_VBR_level(s->glopts, avctx->global_quality);
        av_log(avctx, AV_LOG_WARNING, "VBR mode is experimental!\n");
    } else {
        twolame_set_bitrate(s->glopts, avctx->bit_rate / 1000);
    }

    if ((ret = twolame_init_params(s->glopts)))
        goto error;

    return 0;
error:
    twolame_encode_close(avctx);
    return ret;
}

static int twolame_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
                                const AVFrame *frame, int *got_packet_ptr)
{
    TWOLAMEContext *s = avctx->priv_data;
    int ret;

    if ((ret = ff_alloc_packet2(avctx, avpkt, MPA_MAX_CODED_FRAME_SIZE)) < 0)
        return ret;

    if (frame) {
        switch (avctx->sample_fmt) {
        case AV_SAMPLE_FMT_FLT:
            ret = twolame_encode_buffer_float32_interleaved(s->glopts,
                                        frame->data[0],
                                        frame->nb_samples,
                                        avpkt->data, avpkt->size);
            break;
        case AV_SAMPLE_FMT_FLTP:
            ret = twolame_encode_buffer_float32(s->glopts,
                                        frame->data[0], frame->data[1],
                                        frame->nb_samples,
                                        avpkt->data, avpkt->size);
            break;
        case AV_SAMPLE_FMT_S16:
            ret = twolame_encode_buffer_interleaved(s->glopts,
                                        frame->data[0],
                                        frame->nb_samples,
                                        avpkt->data, avpkt->size);
            break;
        case AV_SAMPLE_FMT_S16P:
            ret = twolame_encode_buffer(s->glopts,
                                        frame->data[0], frame->data[1],
                                        frame->nb_samples,
                                        avpkt->data, avpkt->size);
            break;
        default:
            return AVERROR_BUG;
        }
    } else {
        ret = twolame_encode_flush(s->glopts, avpkt->data, avpkt->size);
    }

    if (ret > 0) {
        avpkt->duration = ff_samples_to_time_base(avctx, avctx->frame_size);
        if (frame) {
            if (frame->pts != AV_NOPTS_VALUE)
                avpkt->pts  = frame->pts;
        } else {
            avpkt->pts = s->next_pts;
        }
        if (avpkt->pts != AV_NOPTS_VALUE)
            s->next_pts = avpkt->pts + avpkt->duration;

        avpkt->size     = ret;
        *got_packet_ptr = 1;
        return 0;
    }

    return ret;
}

#define OFFSET(x) offsetof(TWOLAMEContext, x)
#define AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
    { "mode",         "Mpeg Mode", OFFSET(mode), AV_OPT_TYPE_INT, { .i64 = TWOLAME_AUTO_MODE }, TWOLAME_AUTO_MODE, TWOLAME_MONO, AE, "mode"},
    { "auto",         NULL,         0, AV_OPT_TYPE_CONST, { .i64 = TWOLAME_AUTO_MODE },          0, 0, AE, "mode" },
    { "stereo",       NULL,         0, AV_OPT_TYPE_CONST, { .i64 = TWOLAME_STEREO },             0, 0, AE, "mode" },
    { "joint_stereo", NULL,         0, AV_OPT_TYPE_CONST, { .i64 = TWOLAME_JOINT_STEREO },       0, 0, AE, "mode" },
    { "dual_channel", NULL,         0, AV_OPT_TYPE_CONST, { .i64 = TWOLAME_DUAL_CHANNEL },       0, 0, AE, "mode" },
    { "mono",         NULL,         0, AV_OPT_TYPE_CONST, { .i64 = TWOLAME_MONO },               0, 0, AE, "mode" },
    { "psymodel",    "Psychoacoustic Model",  OFFSET(psymodel), AV_OPT_TYPE_INT, { .i64 = 3 }, -1, 4, AE},
    { "energy_levels","enable energy levels", OFFSET(energy),   AV_OPT_TYPE_INT, { .i64 = 0 },  0, 1, AE},
    { "error_protection","enable CRC error protection", OFFSET(error_protection), AV_OPT_TYPE_INT, { .i64 = 0 },  0, 1, AE},
    { "copyright",    "set MPEG Audio Copyright flag",  OFFSET(copyright), AV_OPT_TYPE_INT, { .i64 = 0 },  0, 1, AE},
    { "original",     "set MPEG Audio Original flag",   OFFSET(original),  AV_OPT_TYPE_INT, { .i64 = 0 },  0, 1, AE},
    { NULL },
};

static const AVClass libtwolame_class = {
    .class_name = "libtwolame encoder",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

AVCodec ff_libtwolame_encoder = {
    .name                  = "libtwolame",
    .type                  = AVMEDIA_TYPE_AUDIO,
    .id                    = AV_CODEC_ID_MP2,
    .priv_data_size        = sizeof(TWOLAMEContext),
    .init                  = twolame_encode_init,
    .encode2               = twolame_encode_frame,
    .close                 = twolame_encode_close,
    .capabilities          = CODEC_CAP_DELAY,
    .sample_fmts           = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
                                                             AV_SAMPLE_FMT_FLTP,
                                                             AV_SAMPLE_FMT_S16,
                                                             AV_SAMPLE_FMT_S16P,
                                                             AV_SAMPLE_FMT_NONE },
    .channel_layouts       = (const uint64_t[]) { AV_CH_LAYOUT_MONO,
                                                  AV_CH_LAYOUT_STEREO,
                                                  0 },
    .supported_samplerates = (const int[]){ 16000, 22050, 24000, 32000, 44100, 48000, 0 },
    .long_name             = NULL_IF_CONFIG_SMALL("libtwolame MP2 (MPEG audio layer 2)"),
    .priv_class            = &libtwolame_class,
};