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 "fmtconvert.h"

41 #include "internal.h"

42 #include "nellymoser.h"

43 #include "sinewin.h"

45 #define BITSTREAM_READER_LE

46 #include "get_bits.h"

49 typedef struct NellyMoserDecodeContext {

50 AVCodecContext* avctx;

51 AVLFG random_state;

52 GetBitContext gb;

53 float scale_bias;

54 AVFloatDSPContext fdsp;

55 FFTContext imdct_ctx;

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

57 float *imdct_out;

58 float *imdct_prev;

59 } NellyMoserDecodeContext;

61 static void nelly_decode_block(NellyMoserDecodeContext *s,

62 const unsigned char block[NELLY_BLOCK_LEN],

63 float audio[NELLY_SAMPLES])

64 {

65 int i,j;

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

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

68 int bits[NELLY_BUF_LEN];

69 unsigned char v;

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

73 bptr = buf;

74 pptr = pows;

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

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

77 if (i > 0)

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

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

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

81 *bptr++ = val;

82 *pptr++ = pval;

83 }

85 }

87 ff_nelly_get_sample_bits(buf, bits);

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

90 aptr = audio + i * NELLY_BUF_LEN;

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

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

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

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

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

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

99 aptr[j] *= -1.0;

100 } else {

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

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

103 }

104 }

105 memset(&aptr[NELLY_FILL_LEN], 0,

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

107

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

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

110 s->imdct_out, ff_sine_128,

111 NELLY_BUF_LEN / 2);

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

113 }

114 }

115

116 static av_cold int decode_init(AVCodecContext * avctx) {

117 NellyMoserDecodeContext *s = avctx->priv_data;

118

119 s->avctx = avctx;

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

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

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

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

124

125 avpriv_float_dsp_init(&s->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);

126

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

128 avctx->sample_fmt = AV_SAMPLE_FMT_FLT;

129

130 /* Generate overlap window */

131 if (!ff_sine_128[127])

132 ff_init_ff_sine_windows(7);

133

134 avctx->channels = 1;

135 avctx->channel_layout = AV_CH_LAYOUT_MONO;

136

137 return 0;

138 }

139

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

141 int *got_frame_ptr, AVPacket *avpkt)

142 {

143 AVFrame *frame = data;

144 const uint8_t *buf = avpkt->data;

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

146 int buf_size = avpkt->size;

147 NellyMoserDecodeContext *s = avctx->priv_data;

148 int blocks, i, ret;

149 float *samples_flt;

150

151 blocks = buf_size / NELLY_BLOCK_LEN;

152

153 if (blocks <= 0) {

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

155 return AVERROR_INVALIDDATA;

156 }

157

158 if (buf_size % NELLY_BLOCK_LEN) {

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

160 buf_size % NELLY_BLOCK_LEN);

161 }

162 /* Normal numbers of blocks for sample rates:

163 * 8000 Hz - 1

164 * 11025 Hz - 2

165 * 16000 Hz - 3

166 * 22050 Hz - 4

167 * 44100 Hz - 8

168 */

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

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

171

172 /* get output buffer */

173 frame->nb_samples = NELLY_SAMPLES * blocks;

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

175 return ret;

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

177

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

179 nelly_decode_block(s, buf, samples_flt);

180 samples_flt += NELLY_SAMPLES;

181 buf += NELLY_BLOCK_LEN;

182 }

183

184 *got_frame_ptr = 1;

185

186 return buf_size;

187 }

188

189 static av_cold int decode_end(AVCodecContext * avctx) {

190 NellyMoserDecodeContext *s = avctx->priv_data;

191

192 ff_mdct_end(&s->imdct_ctx);

193

194 return 0;

195 }

196

197 AVCodec ff_nellymoser_decoder = {

198 .name = "nellymoser",

199 .type = AVMEDIA_TYPE_AUDIO,

200 .id = AV_CODEC_ID_NELLYMOSER,

201 .priv_data_size = sizeof(NellyMoserDecodeContext),

202 .init = decode_init,

203 .close = decode_end,

204 .decode = decode_tag,

205 .capabilities = CODEC_CAP_DR1 | CODEC_CAP_PARAM_CHANGE,

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

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

208 AV_SAMPLE_FMT_NONE },

209 };

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