FFmpeg: libavcodec/nellymoserdec.c Source File

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libavcodec

nellymoserdec.c

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1 /*

2 * NellyMoser audio decoder

4 * 539459aeb7d425140b62a3ec7dbf6dc8e408a306, and

5 * 520e17cd55896441042b14df2566a6eb610ed444

7 * Benjamin Larsson

8 *

9 * Permission is hereby granted, free of charge, to any person obtaining a

10 * copy of this software and associated documentation files (the "Software"),

11 * to deal in the Software without restriction, including without limitation

12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

13 * and/or sell copies of the Software, and to permit persons to whom the

14 * Software is furnished to do so, subject to the following conditions:

15 *

16 * The above copyright notice and this permission notice shall be included in

17 * all copies or substantial portions of the Software.

18 *

19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

22 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

24 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

25 * DEALINGS IN THE SOFTWARE.

26 */

28 /**

29 * @file

30 * The 3 alphanumeric copyright notices are md5summed they are from the original

31 * implementors. The original code is available from http://code.google.com/p/nelly2pcm/

32 */

34 #include "libavutil/channel_layout.h"

35 #include "libavutil/float_dsp.h"

36 #include "libavutil/lfg.h"

37 #include "libavutil/random_seed.h"

38 #include "avcodec.h"

39 #include "fft.h"

40 #include "internal.h"

41 #include "nellymoser.h"

42 #include "sinewin.h"

44 #define BITSTREAM_READER_LE

45 #include "get_bits.h"

48 typedef struct NellyMoserDecodeContext {

49 AVCodecContext* avctx;

50 AVLFG random_state;

51 GetBitContext gb;

52 float scale_bias;

53 AVFloatDSPContext *fdsp;

54 FFTContext imdct_ctx;

55 DECLARE_ALIGNED(32, float, imdct_buf)[2][NELLY_BUF_LEN];

56 float *imdct_out;

57 float *imdct_prev;

58 } NellyMoserDecodeContext;

60 static void nelly_decode_block(NellyMoserDecodeContext *s,

61 const unsigned char block[NELLY_BLOCK_LEN],

62 float audio[NELLY_SAMPLES])

63 {

64 int i,j;

65 float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];

66 float *aptr, *bptr, *pptr, val, pval;

67 int bits[NELLY_BUF_LEN];

68 unsigned char v;

70 init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);

72 bptr = buf;

73 pptr = pows;

74 val = ff_nelly_init_table[get_bits(&s->gb, 6)];

75 for (i=0 ; i<NELLY_BANDS ; i++) {

76 if (i > 0)

77 val += ff_nelly_delta_table[get_bits(&s->gb, 5)];

78 pval = -pow(2, val/2048) * s->scale_bias;

79 for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) {

80 *bptr++ = val;

81 *pptr++ = pval;

82 }

84 }

86 ff_nelly_get_sample_bits(buf, bits);

88 for (i = 0; i < 2; i++) {

89 aptr = audio + i * NELLY_BUF_LEN;

91 init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);

92 skip_bits_long(&s->gb, NELLY_HEADER_BITS + i*NELLY_DETAIL_BITS);

94 for (j = 0; j < NELLY_FILL_LEN; j++) {

95 if (bits[j] <= 0) {

96 aptr[j] = M_SQRT1_2*pows[j];

97 if (av_lfg_get(&s->random_state) & 1)

98 aptr[j] *= -1.0;

99 } else {

100 v = get_bits(&s->gb, bits[j]);

101 aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j];

102 }

103 }

104 memset(&aptr[NELLY_FILL_LEN], 0,

105 (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));

106

107 s->imdct_ctx.imdct_half(&s->imdct_ctx, s->imdct_out, aptr);

108 s->fdsp->vector_fmul_window(aptr, s->imdct_prev + NELLY_BUF_LEN / 2,

109 s->imdct_out, ff_sine_128,

110 NELLY_BUF_LEN / 2);

111 FFSWAP(float *, s->imdct_out, s->imdct_prev);

112 }

113 }

114

115 static av_cold int decode_init(AVCodecContext * avctx) {

116 NellyMoserDecodeContext *s = avctx->priv_data;

117

118 s->avctx = avctx;

119 s->imdct_out = s->imdct_buf[0];

120 s->imdct_prev = s->imdct_buf[1];

121 av_lfg_init(&s->random_state, 0);

122 ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0);

123

124 s->fdsp = avpriv_float_dsp_alloc(avctx->flags & CODEC_FLAG_BITEXACT);

125 if (!s->fdsp)

126 return AVERROR(ENOMEM);

127

128 s->scale_bias = 1.0/(32768*8);

129 avctx->sample_fmt = AV_SAMPLE_FMT_FLT;

130

131 /* Generate overlap window */

132 if (!ff_sine_128[127])

133 ff_init_ff_sine_windows(7);

134

135 avctx->channels = 1;

136 avctx->channel_layout = AV_CH_LAYOUT_MONO;

137

138 return 0;

139 }

140

141 static int decode_tag(AVCodecContext *avctx, void *data,

142 int *got_frame_ptr, AVPacket *avpkt)

143 {

144 AVFrame *frame = data;

145 const uint8_t *buf = avpkt->data;

146 const uint8_t *side=av_packet_get_side_data(avpkt, 'F', NULL);

147 int buf_size = avpkt->size;

148 NellyMoserDecodeContext *s = avctx->priv_data;

149 int blocks, i, ret;

150 float *samples_flt;

151

152 blocks = buf_size / NELLY_BLOCK_LEN;

153

154 if (blocks <= 0) {

155 av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");

156 return AVERROR_INVALIDDATA;

157 }

158

159 if (buf_size % NELLY_BLOCK_LEN) {

160 av_log(avctx, AV_LOG_WARNING, "Leftover bytes: %d.\n",

161 buf_size % NELLY_BLOCK_LEN);

162 }

163 /* Normal numbers of blocks for sample rates:

164 * 8000 Hz - 1

165 * 11025 Hz - 2

166 * 16000 Hz - 3

167 * 22050 Hz - 4

168 * 44100 Hz - 8

169 */

170 if(side && blocks>1 && avctx->sample_rate%11025==0 && (1<<((side[0]>>2)&3)) == blocks)

171 avctx->sample_rate= 11025*(blocks/2);

172

173 /* get output buffer */

174 frame->nb_samples = NELLY_SAMPLES * blocks;

175 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

176 return ret;

177 samples_flt = (float *)frame->data[0];

178

179 for (i=0 ; i<blocks ; i++) {

180 nelly_decode_block(s, buf, samples_flt);

181 samples_flt += NELLY_SAMPLES;

182 buf += NELLY_BLOCK_LEN;

183 }

184

185 *got_frame_ptr = 1;

186

187 return buf_size;

188 }

189

190 static av_cold int decode_end(AVCodecContext * avctx) {

191 NellyMoserDecodeContext *s = avctx->priv_data;

192

193 ff_mdct_end(&s->imdct_ctx);

194 av_freep(&s->fdsp);

195

196 return 0;

197 }

198

199 AVCodec ff_nellymoser_decoder = {

200 .name = "nellymoser",

201 .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),

202 .type = AVMEDIA_TYPE_AUDIO,

203 .id = AV_CODEC_ID_NELLYMOSER,

204 .priv_data_size = sizeof(NellyMoserDecodeContext),

205 .init = decode_init,

206 .close = decode_end,

207 .decode = decode_tag,

208 .capabilities = CODEC_CAP_DR1 | CODEC_CAP_PARAM_CHANGE,

209 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,

210 AV_SAMPLE_FMT_NONE },

211 };

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