[deb_ffmpeg.git] / ffmpeg / libavcodec / mpc7.c

/*
 * Musepack SV7 decoder
 * Copyright (c) 2006 Konstantin Shishkov
 *
 * 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
 * MPEG Audio Layer 1/2 -like codec with frames of 1152 samples
 * divided into 32 subbands.
 */

#include "libavutil/channel_layout.h"
#include "libavutil/internal.h"
#include "libavutil/lfg.h"
#include "avcodec.h"
#include "get_bits.h"
#include "internal.h"
#include "mpegaudiodsp.h"

#include "mpc.h"
#include "mpc7data.h"

static VLC scfi_vlc, dscf_vlc, hdr_vlc, quant_vlc[MPC7_QUANT_VLC_TABLES][2];

static const uint16_t quant_offsets[MPC7_QUANT_VLC_TABLES*2 + 1] =
{
       0, 512, 1024, 1536, 2052, 2564, 3076, 3588, 4100, 4612, 5124,
       5636, 6164, 6676, 7224
};


static av_cold int mpc7_decode_init(AVCodecContext * avctx)
{
    int i, j;
    MPCContext *c = avctx->priv_data;
    GetBitContext gb;
    LOCAL_ALIGNED_16(uint8_t, buf, [16]);
    static int vlc_initialized = 0;

    static VLC_TYPE scfi_table[1 << MPC7_SCFI_BITS][2];
    static VLC_TYPE dscf_table[1 << MPC7_DSCF_BITS][2];
    static VLC_TYPE hdr_table[1 << MPC7_HDR_BITS][2];
    static VLC_TYPE quant_tables[7224][2];

    /* Musepack SV7 is always stereo */
    if (avctx->channels != 2) {
        avpriv_request_sample(avctx, "%d channels", avctx->channels);
        return AVERROR_PATCHWELCOME;
    }

    if(avctx->extradata_size < 16){
        av_log(avctx, AV_LOG_ERROR, "Too small extradata size (%i)!\n", avctx->extradata_size);
        return -1;
    }
    memset(c->oldDSCF, 0, sizeof(c->oldDSCF));
    av_lfg_init(&c->rnd, 0xDEADBEEF);
    ff_bswapdsp_init(&c->bdsp);
    ff_mpadsp_init(&c->mpadsp);
    c->bdsp.bswap_buf((uint32_t *) buf, (const uint32_t *) avctx->extradata, 4);
    ff_mpc_init();
    init_get_bits(&gb, buf, 128);

    c->IS = get_bits1(&gb);
    c->MSS = get_bits1(&gb);
    c->maxbands = get_bits(&gb, 6);
    if(c->maxbands >= BANDS){
        av_log(avctx, AV_LOG_ERROR, "Too many bands: %i\n", c->maxbands);
        return -1;
    }
    skip_bits_long(&gb, 88);
    c->gapless = get_bits1(&gb);
    c->lastframelen = get_bits(&gb, 11);
    av_log(avctx, AV_LOG_DEBUG, "IS: %d, MSS: %d, TG: %d, LFL: %d, bands: %d\n",
            c->IS, c->MSS, c->gapless, c->lastframelen, c->maxbands);
    c->frames_to_skip = 0;

    avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
    avctx->channel_layout = AV_CH_LAYOUT_STEREO;

    if(vlc_initialized) return 0;
    av_log(avctx, AV_LOG_DEBUG, "Initing VLC\n");
    scfi_vlc.table = scfi_table;
    scfi_vlc.table_allocated = 1 << MPC7_SCFI_BITS;
    if(init_vlc(&scfi_vlc, MPC7_SCFI_BITS, MPC7_SCFI_SIZE,
                &mpc7_scfi[1], 2, 1,
                &mpc7_scfi[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
        av_log(avctx, AV_LOG_ERROR, "Cannot init SCFI VLC\n");
        return -1;
    }
    dscf_vlc.table = dscf_table;
    dscf_vlc.table_allocated = 1 << MPC7_DSCF_BITS;
    if(init_vlc(&dscf_vlc, MPC7_DSCF_BITS, MPC7_DSCF_SIZE,
                &mpc7_dscf[1], 2, 1,
                &mpc7_dscf[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
        av_log(avctx, AV_LOG_ERROR, "Cannot init DSCF VLC\n");
        return -1;
    }
    hdr_vlc.table = hdr_table;
    hdr_vlc.table_allocated = 1 << MPC7_HDR_BITS;
    if(init_vlc(&hdr_vlc, MPC7_HDR_BITS, MPC7_HDR_SIZE,
                &mpc7_hdr[1], 2, 1,
                &mpc7_hdr[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
        av_log(avctx, AV_LOG_ERROR, "Cannot init HDR VLC\n");
        return -1;
    }
    for(i = 0; i < MPC7_QUANT_VLC_TABLES; i++){
        for(j = 0; j < 2; j++){
            quant_vlc[i][j].table = &quant_tables[quant_offsets[i*2 + j]];
            quant_vlc[i][j].table_allocated = quant_offsets[i*2 + j + 1] - quant_offsets[i*2 + j];
            if(init_vlc(&quant_vlc[i][j], 9, mpc7_quant_vlc_sizes[i],
                        &mpc7_quant_vlc[i][j][1], 4, 2,
                        &mpc7_quant_vlc[i][j][0], 4, 2, INIT_VLC_USE_NEW_STATIC)){
                av_log(avctx, AV_LOG_ERROR, "Cannot init QUANT VLC %i,%i\n",i,j);
                return -1;
            }
        }
    }
    vlc_initialized = 1;

    return 0;
}

/**
 * Fill samples for given subband
 */
static inline void idx_to_quant(MPCContext *c, GetBitContext *gb, int idx, int *dst)
{
    int i, i1, t;
    switch(idx){
    case -1:
        for(i = 0; i < SAMPLES_PER_BAND; i++){
            *dst++ = (av_lfg_get(&c->rnd) & 0x3FC) - 510;
        }
        break;
    case 1:
        i1 = get_bits1(gb);
        for(i = 0; i < SAMPLES_PER_BAND/3; i++){
            t = get_vlc2(gb, quant_vlc[0][i1].table, 9, 2);
            *dst++ = mpc7_idx30[t];
            *dst++ = mpc7_idx31[t];
            *dst++ = mpc7_idx32[t];
        }
        break;
    case 2:
        i1 = get_bits1(gb);
        for(i = 0; i < SAMPLES_PER_BAND/2; i++){
            t = get_vlc2(gb, quant_vlc[1][i1].table, 9, 2);
            *dst++ = mpc7_idx50[t];
            *dst++ = mpc7_idx51[t];
        }
        break;
    case  3: case  4: case  5: case  6: case  7:
        i1 = get_bits1(gb);
        for(i = 0; i < SAMPLES_PER_BAND; i++)
            *dst++ = get_vlc2(gb, quant_vlc[idx-1][i1].table, 9, 2) - mpc7_quant_vlc_off[idx-1];
        break;
    case  8: case  9: case 10: case 11: case 12:
    case 13: case 14: case 15: case 16: case 17:
        t = (1 << (idx - 2)) - 1;
        for(i = 0; i < SAMPLES_PER_BAND; i++)
            *dst++ = get_bits(gb, idx - 1) - t;
        break;
    default: // case 0 and -2..-17
        return;
    }
}

static int get_scale_idx(GetBitContext *gb, int ref)
{
    int t = get_vlc2(gb, dscf_vlc.table, MPC7_DSCF_BITS, 1) - 7;
    if (t == 8)
        return get_bits(gb, 6);
    return ref + t;
}

static int mpc7_decode_frame(AVCodecContext * avctx, void *data,
                             int *got_frame_ptr, AVPacket *avpkt)
{
    AVFrame *frame     = data;
    const uint8_t *buf = avpkt->data;
    int buf_size;
    MPCContext *c = avctx->priv_data;
    GetBitContext gb;
    int i, ch;
    int mb = -1;
    Band *bands = c->bands;
    int off, ret, last_frame, skip;
    int bits_used, bits_avail;

    memset(bands, 0, sizeof(*bands) * (c->maxbands + 1));

    buf_size = avpkt->size & ~3;
    if (buf_size <= 0) {
        av_log(avctx, AV_LOG_ERROR, "packet size is too small (%i bytes)\n",
               avpkt->size);
        return AVERROR_INVALIDDATA;
    }
    if (buf_size != avpkt->size) {
        av_log(avctx, AV_LOG_WARNING, "packet size is not a multiple of 4. "
               "extra bytes at the end will be skipped.\n");
    }

    skip       = buf[0];
    last_frame = buf[1];
    buf       += 4;
    buf_size  -= 4;

    /* get output buffer */
    frame->nb_samples = MPC_FRAME_SIZE;
    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
        return ret;

    av_fast_padded_malloc(&c->bits, &c->buf_size, buf_size);
    if (!c->bits)
        return AVERROR(ENOMEM);
    c->bdsp.bswap_buf((uint32_t *) c->bits, (const uint32_t *) buf,
                      buf_size >> 2);
    init_get_bits(&gb, c->bits, buf_size * 8);
    skip_bits_long(&gb, skip);

    /* read subband indexes */
    for(i = 0; i <= c->maxbands; i++){
        for(ch = 0; ch < 2; ch++){
            int t = 4;
            if(i) t = get_vlc2(&gb, hdr_vlc.table, MPC7_HDR_BITS, 1) - 5;
            if(t == 4) bands[i].res[ch] = get_bits(&gb, 4);
            else bands[i].res[ch] = bands[i-1].res[ch] + t;
            if (bands[i].res[ch] < -1 || bands[i].res[ch] > 17) {
                av_log(avctx, AV_LOG_ERROR, "subband index invalid\n");
                return AVERROR_INVALIDDATA;
            }
        }

        if(bands[i].res[0] || bands[i].res[1]){
            mb = i;
            if(c->MSS) bands[i].msf = get_bits1(&gb);
        }
    }
    /* get scale indexes coding method */
    for(i = 0; i <= mb; i++)
        for(ch = 0; ch < 2; ch++)
            if(bands[i].res[ch]) bands[i].scfi[ch] = get_vlc2(&gb, scfi_vlc.table, MPC7_SCFI_BITS, 1);
    /* get scale indexes */
    for(i = 0; i <= mb; i++){
        for(ch = 0; ch < 2; ch++){
            if(bands[i].res[ch]){
                bands[i].scf_idx[ch][2] = c->oldDSCF[ch][i];
                bands[i].scf_idx[ch][0] = get_scale_idx(&gb, bands[i].scf_idx[ch][2]);
                switch(bands[i].scfi[ch]){
                case 0:
                    bands[i].scf_idx[ch][1] = get_scale_idx(&gb, bands[i].scf_idx[ch][0]);
                    bands[i].scf_idx[ch][2] = get_scale_idx(&gb, bands[i].scf_idx[ch][1]);
                    break;
                case 1:
                    bands[i].scf_idx[ch][1] = get_scale_idx(&gb, bands[i].scf_idx[ch][0]);
                    bands[i].scf_idx[ch][2] = bands[i].scf_idx[ch][1];
                    break;
                case 2:
                    bands[i].scf_idx[ch][1] = bands[i].scf_idx[ch][0];
                    bands[i].scf_idx[ch][2] = get_scale_idx(&gb, bands[i].scf_idx[ch][1]);
                    break;
                case 3:
                    bands[i].scf_idx[ch][2] = bands[i].scf_idx[ch][1] = bands[i].scf_idx[ch][0];
                    break;
                }
                c->oldDSCF[ch][i] = bands[i].scf_idx[ch][2];
            }
        }
    }
    /* get quantizers */
    memset(c->Q, 0, sizeof(c->Q));
    off = 0;
    for(i = 0; i < BANDS; i++, off += SAMPLES_PER_BAND)
        for(ch = 0; ch < 2; ch++)
            idx_to_quant(c, &gb, bands[i].res[ch], c->Q[ch] + off);

    ff_mpc_dequantize_and_synth(c, mb, (int16_t **)frame->extended_data, 2);
    if(last_frame)
        frame->nb_samples = c->lastframelen;

    bits_used = get_bits_count(&gb);
    bits_avail = buf_size * 8;
    if (!last_frame && ((bits_avail < bits_used) || (bits_used + 32 <= bits_avail))) {
        av_log(avctx, AV_LOG_ERROR, "Error decoding frame: used %i of %i bits\n", bits_used, bits_avail);
        return -1;
    }
    if(c->frames_to_skip){
        c->frames_to_skip--;
        *got_frame_ptr = 0;
        return avpkt->size;
    }

    *got_frame_ptr = 1;

    return avpkt->size;
}

static void mpc7_decode_flush(AVCodecContext *avctx)
{
    MPCContext *c = avctx->priv_data;

    memset(c->oldDSCF, 0, sizeof(c->oldDSCF));
    c->frames_to_skip = 32;
}

static av_cold int mpc7_decode_close(AVCodecContext *avctx)
{
    MPCContext *c = avctx->priv_data;
    av_freep(&c->bits);
    c->buf_size = 0;
    return 0;
}

AVCodec ff_mpc7_decoder = {
    .name           = "mpc7",
    .long_name      = NULL_IF_CONFIG_SMALL("Musepack SV7"),
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_MUSEPACK7,
    .priv_data_size = sizeof(MPCContext),
    .init           = mpc7_decode_init,
    .close          = mpc7_decode_close,
    .decode         = mpc7_decode_frame,
    .flush          = mpc7_decode_flush,
    .capabilities   = CODEC_CAP_DR1,
    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
                                                      AV_SAMPLE_FMT_NONE },
};
Commit	Line	Data
2ba45a60 DM	1	/*
	2	* Musepack SV7 decoder
	3	* Copyright (c) 2006 Konstantin Shishkov
	4	*
	5	* This file is part of FFmpeg.
	6	*
	7	* FFmpeg is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU Lesser General Public
	9	* License as published by the Free Software Foundation; either
	10	* version 2.1 of the License, or (at your option) any later version.
	11	*
	12	* FFmpeg is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	15	* Lesser General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU Lesser General Public
	18	* License along with FFmpeg; if not, write to the Free Software
	19	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	20	*/
	21
	22	/**
	23	* @file
	24	* MPEG Audio Layer 1/2 -like codec with frames of 1152 samples
	25	* divided into 32 subbands.
	26	*/
	27
	28	#include "libavutil/channel_layout.h"
	29	#include "libavutil/internal.h"
	30	#include "libavutil/lfg.h"
	31	#include "avcodec.h"
	32	#include "get_bits.h"
	33	#include "internal.h"
	34	#include "mpegaudiodsp.h"
	35
	36	#include "mpc.h"
	37	#include "mpc7data.h"
	38
	39	static VLC scfi_vlc, dscf_vlc, hdr_vlc, quant_vlc[MPC7_QUANT_VLC_TABLES][2];
	40
	41	static const uint16_t quant_offsets[MPC7_QUANT_VLC_TABLES*2 + 1] =
	42	{
	43	0, 512, 1024, 1536, 2052, 2564, 3076, 3588, 4100, 4612, 5124,
	44	5636, 6164, 6676, 7224
	45	};
	46
	47
	48	static av_cold int mpc7_decode_init(AVCodecContext * avctx)
	49	{
	50	int i, j;
	51	MPCContext *c = avctx->priv_data;
	52	GetBitContext gb;
	53	LOCAL_ALIGNED_16(uint8_t, buf, [16]);
	54	static int vlc_initialized = 0;
	55
	56	static VLC_TYPE scfi_table[1 << MPC7_SCFI_BITS][2];
	57	static VLC_TYPE dscf_table[1 << MPC7_DSCF_BITS][2];
	58	static VLC_TYPE hdr_table[1 << MPC7_HDR_BITS][2];
	59	static VLC_TYPE quant_tables[7224][2];
	60
	61	/* Musepack SV7 is always stereo */
	62	if (avctx->channels != 2) {
	63	avpriv_request_sample(avctx, "%d channels", avctx->channels);
	64	return AVERROR_PATCHWELCOME;
65	}
66
67	if(avctx->extradata_size < 16){
68	av_log(avctx, AV_LOG_ERROR, "Too small extradata size (%i)!\n", avctx->extradata_size);
69	return -1;
70	}
71	memset(c->oldDSCF, 0, sizeof(c->oldDSCF));
72	av_lfg_init(&c->rnd, 0xDEADBEEF);
73	ff_bswapdsp_init(&c->bdsp);
74	ff_mpadsp_init(&c->mpadsp);
75	c->bdsp.bswap_buf((uint32_t ) buf, (const uint32_t ) avctx->extradata, 4);
76	ff_mpc_init();
77	init_get_bits(&gb, buf, 128);
78
79	c->IS = get_bits1(&gb);
80	c->MSS = get_bits1(&gb);
81	c->maxbands = get_bits(&gb, 6);
82	if(c->maxbands >= BANDS){
83	av_log(avctx, AV_LOG_ERROR, "Too many bands: %i\n", c->maxbands);
84	return -1;
85	}
86	skip_bits_long(&gb, 88);
87	c->gapless = get_bits1(&gb);
88	c->lastframelen = get_bits(&gb, 11);
89	av_log(avctx, AV_LOG_DEBUG, "IS: %d, MSS: %d, TG: %d, LFL: %d, bands: %d\n",
90	c->IS, c->MSS, c->gapless, c->lastframelen, c->maxbands);
91	c->frames_to_skip = 0;
92
93	avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
94	avctx->channel_layout = AV_CH_LAYOUT_STEREO;
95
96	if(vlc_initialized) return 0;
97	av_log(avctx, AV_LOG_DEBUG, "Initing VLC\n");
98	scfi_vlc.table = scfi_table;
99	scfi_vlc.table_allocated = 1 << MPC7_SCFI_BITS;
100	if(init_vlc(&scfi_vlc, MPC7_SCFI_BITS, MPC7_SCFI_SIZE,
101	&mpc7_scfi[1], 2, 1,
102	&mpc7_scfi[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
103	av_log(avctx, AV_LOG_ERROR, "Cannot init SCFI VLC\n");
104	return -1;
105	}
106	dscf_vlc.table = dscf_table;
107	dscf_vlc.table_allocated = 1 << MPC7_DSCF_BITS;
108	if(init_vlc(&dscf_vlc, MPC7_DSCF_BITS, MPC7_DSCF_SIZE,
109	&mpc7_dscf[1], 2, 1,
110	&mpc7_dscf[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
111	av_log(avctx, AV_LOG_ERROR, "Cannot init DSCF VLC\n");
112	return -1;
113	}
114	hdr_vlc.table = hdr_table;
115	hdr_vlc.table_allocated = 1 << MPC7_HDR_BITS;
116	if(init_vlc(&hdr_vlc, MPC7_HDR_BITS, MPC7_HDR_SIZE,
117	&mpc7_hdr[1], 2, 1,
118	&mpc7_hdr[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
119	av_log(avctx, AV_LOG_ERROR, "Cannot init HDR VLC\n");
120	return -1;
121	}
122	for(i = 0; i < MPC7_QUANT_VLC_TABLES; i++){
123	for(j = 0; j < 2; j++){
124	quant_vlc[i][j].table = &quant_tables[quant_offsets[i*2 + j]];
125	quant_vlc[i][j].table_allocated = quant_offsets[i2 + j + 1] - quant_offsets[i2 + j];
126	if(init_vlc(&quant_vlc[i][j], 9, mpc7_quant_vlc_sizes[i],
127	&mpc7_quant_vlc[i][j][1], 4, 2,
128	&mpc7_quant_vlc[i][j][0], 4, 2, INIT_VLC_USE_NEW_STATIC)){
129	av_log(avctx, AV_LOG_ERROR, "Cannot init QUANT VLC %i,%i\n",i,j);
130	return -1;
131	}
132	}
133	}
134	vlc_initialized = 1;
135
136	return 0;
137	}
138
139	/**
140	* Fill samples for given subband
141	*/
142	static inline void idx_to_quant(MPCContext c, GetBitContext gb, int idx, int *dst)
143	{
144	int i, i1, t;
145	switch(idx){
146	case -1:
147	for(i = 0; i < SAMPLES_PER_BAND; i++){
148	*dst++ = (av_lfg_get(&c->rnd) & 0x3FC) - 510;
149	}
150	break;
151	case 1:
152	i1 = get_bits1(gb);
153	for(i = 0; i < SAMPLES_PER_BAND/3; i++){
154	t = get_vlc2(gb, quant_vlc[0][i1].table, 9, 2);
155	*dst++ = mpc7_idx30[t];
156	*dst++ = mpc7_idx31[t];
157	*dst++ = mpc7_idx32[t];
158	}
159	break;
160	case 2:
161	i1 = get_bits1(gb);
162	for(i = 0; i < SAMPLES_PER_BAND/2; i++){
163	t = get_vlc2(gb, quant_vlc[1][i1].table, 9, 2);
164	*dst++ = mpc7_idx50[t];
165	*dst++ = mpc7_idx51[t];
166	}
167	break;
168	case 3: case 4: case 5: case 6: case 7:
169	i1 = get_bits1(gb);
170	for(i = 0; i < SAMPLES_PER_BAND; i++)
171	*dst++ = get_vlc2(gb, quant_vlc[idx-1][i1].table, 9, 2) - mpc7_quant_vlc_off[idx-1];
172	break;
173	case 8: case 9: case 10: case 11: case 12:
174	case 13: case 14: case 15: case 16: case 17:
175	t = (1 << (idx - 2)) - 1;
176	for(i = 0; i < SAMPLES_PER_BAND; i++)
177	*dst++ = get_bits(gb, idx - 1) - t;
178	break;
179	default: // case 0 and -2..-17
180	return;
181	}
182	}
183
184	static int get_scale_idx(GetBitContext *gb, int ref)
185	{
186	int t = get_vlc2(gb, dscf_vlc.table, MPC7_DSCF_BITS, 1) - 7;
187	if (t == 8)
188	return get_bits(gb, 6);
189	return ref + t;
190	}
191
192	static int mpc7_decode_frame(AVCodecContext * avctx, void *data,
193	int got_frame_ptr, AVPacket avpkt)
194	{
195	AVFrame *frame = data;
196	const uint8_t *buf = avpkt->data;
197	int buf_size;
198	MPCContext *c = avctx->priv_data;
199	GetBitContext gb;
200	int i, ch;
201	int mb = -1;
202	Band *bands = c->bands;
203	int off, ret, last_frame, skip;
204	int bits_used, bits_avail;
205
206	memset(bands, 0, sizeof(bands) (c->maxbands + 1));
207
208	buf_size = avpkt->size & ~3;
209	if (buf_size <= 0) {
210	av_log(avctx, AV_LOG_ERROR, "packet size is too small (%i bytes)\n",
211	avpkt->size);
212	return AVERROR_INVALIDDATA;
213	}
214	if (buf_size != avpkt->size) {
215	av_log(avctx, AV_LOG_WARNING, "packet size is not a multiple of 4. "
216	"extra bytes at the end will be skipped.\n");
217	}
218
219	skip = buf[0];
220	last_frame = buf[1];
221	buf += 4;
222	buf_size -= 4;
223
224	/* get output buffer */
225	frame->nb_samples = MPC_FRAME_SIZE;
226	if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
227	return ret;
228
229	av_fast_padded_malloc(&c->bits, &c->buf_size, buf_size);
230	if (!c->bits)
231	return AVERROR(ENOMEM);
232	c->bdsp.bswap_buf((uint32_t ) c->bits, (const uint32_t ) buf,
233	buf_size >> 2);
234	init_get_bits(&gb, c->bits, buf_size * 8);
235	skip_bits_long(&gb, skip);
236
237	/* read subband indexes */
238	for(i = 0; i <= c->maxbands; i++){
239	for(ch = 0; ch < 2; ch++){
240	int t = 4;
241	if(i) t = get_vlc2(&gb, hdr_vlc.table, MPC7_HDR_BITS, 1) - 5;
242	if(t == 4) bands[i].res[ch] = get_bits(&gb, 4);
243	else bands[i].res[ch] = bands[i-1].res[ch] + t;
244	if (bands[i].res[ch] < -1 \|\| bands[i].res[ch] > 17) {
245	av_log(avctx, AV_LOG_ERROR, "subband index invalid\n");
246	return AVERROR_INVALIDDATA;
247	}
248	}
249
250	if(bands[i].res[0] \|\| bands[i].res[1]){
251	mb = i;
252	if(c->MSS) bands[i].msf = get_bits1(&gb);
253	}
254	}
255	/* get scale indexes coding method */
256	for(i = 0; i <= mb; i++)
257	for(ch = 0; ch < 2; ch++)
258	if(bands[i].res[ch]) bands[i].scfi[ch] = get_vlc2(&gb, scfi_vlc.table, MPC7_SCFI_BITS, 1);
259	/* get scale indexes */
260	for(i = 0; i <= mb; i++){
261	for(ch = 0; ch < 2; ch++){
262	if(bands[i].res[ch]){
263	bands[i].scf_idx[ch][2] = c->oldDSCF[ch][i];
264	bands[i].scf_idx[ch][0] = get_scale_idx(&gb, bands[i].scf_idx[ch][2]);
265	switch(bands[i].scfi[ch]){
266	case 0:
267	bands[i].scf_idx[ch][1] = get_scale_idx(&gb, bands[i].scf_idx[ch][0]);
268	bands[i].scf_idx[ch][2] = get_scale_idx(&gb, bands[i].scf_idx[ch][1]);
269	break;
270	case 1:
271	bands[i].scf_idx[ch][1] = get_scale_idx(&gb, bands[i].scf_idx[ch][0]);
272	bands[i].scf_idx[ch][2] = bands[i].scf_idx[ch][1];
273	break;
274	case 2:
275	bands[i].scf_idx[ch][1] = bands[i].scf_idx[ch][0];
276	bands[i].scf_idx[ch][2] = get_scale_idx(&gb, bands[i].scf_idx[ch][1]);
277	break;
278	case 3:
279	bands[i].scf_idx[ch][2] = bands[i].scf_idx[ch][1] = bands[i].scf_idx[ch][0];
280	break;
281	}
282	c->oldDSCF[ch][i] = bands[i].scf_idx[ch][2];
283	}
284	}
285	}
286	/* get quantizers */
287	memset(c->Q, 0, sizeof(c->Q));
288	off = 0;
289	for(i = 0; i < BANDS; i++, off += SAMPLES_PER_BAND)
290	for(ch = 0; ch < 2; ch++)
291	idx_to_quant(c, &gb, bands[i].res[ch], c->Q[ch] + off);
292
293	ff_mpc_dequantize_and_synth(c, mb, (int16_t **)frame->extended_data, 2);
294	if(last_frame)
295	frame->nb_samples = c->lastframelen;
296
297	bits_used = get_bits_count(&gb);
298	bits_avail = buf_size * 8;
299	if (!last_frame && ((bits_avail < bits_used) \|\| (bits_used + 32 <= bits_avail))) {
300	av_log(avctx, AV_LOG_ERROR, "Error decoding frame: used %i of %i bits\n", bits_used, bits_avail);
301	return -1;
302	}
303	if(c->frames_to_skip){
304	c->frames_to_skip--;
305	*got_frame_ptr = 0;
306	return avpkt->size;
307	}
308
309	*got_frame_ptr = 1;
310
311	return avpkt->size;
312	}
313
314	static void mpc7_decode_flush(AVCodecContext *avctx)
315	{
316	MPCContext *c = avctx->priv_data;
317
318	memset(c->oldDSCF, 0, sizeof(c->oldDSCF));
319	c->frames_to_skip = 32;
320	}
321
322	static av_cold int mpc7_decode_close(AVCodecContext *avctx)
323	{
324	MPCContext *c = avctx->priv_data;
325	av_freep(&c->bits);
326	c->buf_size = 0;
327	return 0;
328	}
329
330	AVCodec ff_mpc7_decoder = {
331	.name = "mpc7",
332	.long_name = NULL_IF_CONFIG_SMALL("Musepack SV7"),
333	.type = AVMEDIA_TYPE_AUDIO,
334	.id = AV_CODEC_ID_MUSEPACK7,
335	.priv_data_size = sizeof(MPCContext),
336	.init = mpc7_decode_init,
337	.close = mpc7_decode_close,
338	.decode = mpc7_decode_frame,
339	.flush = mpc7_decode_flush,
340	.capabilities = CODEC_CAP_DR1,
341	.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
342	AV_SAMPLE_FMT_NONE },
343	};