unsigned int dither_state;
} MPADecodeContext;
+/**
+ * Context for MP3On4 decoder
+ */
+typedef struct MP3On4DecodeContext {
+ int frames; ///< number of mp3 frames per block (number of mp3 decoder instances)
+ int chan_cfg; ///< channel config number
+ MPADecodeContext *mp3decctx[5]; ///< MPADecodeContext for every decoder instance
+} MP3On4DecodeContext;
+
/* layer 3 "granule" */
typedef struct GranuleDef {
uint8_t scfsi;
}
+/* Next 3 arrays are indexed by channel config number (passed via codecdata) */
+static int mp3Frames[16] = {0,1,1,2,3,3,4,5,2}; /* number of mp3 decoder instances */
+static int mp3Channels[16] = {0,1,2,3,4,5,6,8,4}; /* total output channels */
+/* offsets into output buffer, assume output order is FL FR BL BR C LFE */
+static int chan_offset[9][5] = {
+ {0},
+ {0}, // C
+ {0}, // FLR
+ {2,0}, // C FLR
+ {2,0,3}, // C FLR BS
+ {4,0,2}, // C FLR BLRS
+ {4,0,2,5}, // C FLR BLRS LFE
+ {4,0,2,6,5}, // C FLR BLRS BLR LFE
+ {0,2} // FLR BLRS
+};
+
+
+static int decode_init_mp3on4(AVCodecContext * avctx)
+{
+ MP3On4DecodeContext *s = avctx->priv_data;
+ int i;
+
+ if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) {
+ av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");
+ return -1;
+ }
+
+ s->chan_cfg = (((unsigned char *)avctx->extradata)[1] >> 3) & 0x0f;
+ s->frames = mp3Frames[s->chan_cfg];
+ if(!s->frames) {
+ av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");
+ return -1;
+ }
+ avctx->channels = mp3Channels[s->chan_cfg];
+
+ /* Init the first mp3 decoder in standard way, so that all tables get builded
+ * We replace avctx->priv_data with the context of the first decoder so that
+ * decode_init() does not have to be changed.
+ * Other decoders will be inited here copying data from the first context
+ */
+ // Allocate zeroed memory for the first decoder context
+ s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));
+ // Put decoder context in place to make init_decode() happy
+ avctx->priv_data = s->mp3decctx[0];
+ decode_init(avctx);
+ // Restore mp3on4 context pointer
+ avctx->priv_data = s;
+ s->mp3decctx[0]->adu_mode = 1; // Set adu mode
+
+ /* Create a separate codec/context for each frame (first is already ok).
+ * Each frame is 1 or 2 channels - up to 5 frames allowed
+ */
+ for (i = 1; i < s->frames; i++) {
+ s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));
+ s->mp3decctx[i]->compute_antialias = s->mp3decctx[0]->compute_antialias;
+ s->mp3decctx[i]->inbuf = &s->mp3decctx[i]->inbuf1[0][BACKSTEP_SIZE];
+ s->mp3decctx[i]->inbuf_ptr = s->mp3decctx[i]->inbuf;
+ s->mp3decctx[i]->adu_mode = 1;
+ }
+
+ return 0;
+}
+
+
+static int decode_close_mp3on4(AVCodecContext * avctx)
+{
+ MP3On4DecodeContext *s = avctx->priv_data;
+ int i;
+
+ for (i = 0; i < s->frames; i++)
+ if (s->mp3decctx[i])
+ av_free(s->mp3decctx[i]);
+
+ return 0;
+}
+
+
+static int decode_frame_mp3on4(AVCodecContext * avctx,
+ void *data, int *data_size,
+ uint8_t * buf, int buf_size)
+{
+ MP3On4DecodeContext *s = avctx->priv_data;
+ MPADecodeContext *m;
+ int len, out_size = 0;
+ uint32_t header;
+ OUT_INT *out_samples = data;
+ OUT_INT decoded_buf[MPA_FRAME_SIZE * MPA_MAX_CHANNELS];
+ OUT_INT *outptr, *bp;
+ int fsize;
+ unsigned char *start2 = buf, *start;
+ int fr, i, j, n;
+ int off = avctx->channels;
+ int *coff = chan_offset[s->chan_cfg];
+
+ len = buf_size;
+
+ // Discard too short frames
+ if (buf_size < HEADER_SIZE) {
+ *data_size = 0;
+ return buf_size;
+ }
+
+ // If only one decoder interleave is not needed
+ outptr = s->frames == 1 ? out_samples : decoded_buf;
+
+ for (fr = 0; fr < s->frames; fr++) {
+ start = start2;
+ fsize = (start[0] << 4) | (start[1] >> 4);
+ start2 += fsize;
+ if (fsize > len)
+ fsize = len;
+ len -= fsize;
+ if (fsize > MPA_MAX_CODED_FRAME_SIZE)
+ fsize = MPA_MAX_CODED_FRAME_SIZE;
+ m = s->mp3decctx[fr];
+ assert (m != NULL);
+ /* copy original to new */
+ m->inbuf_ptr = m->inbuf + fsize;
+ memcpy(m->inbuf, start, fsize);
+
+ // Get header
+ header = (m->inbuf[0] << 24) | (m->inbuf[1] << 16) |
+ (m->inbuf[2] << 8) | m->inbuf[3] | 0xfff00000;
+
+ if (ff_mpa_check_header(header) < 0) { // Bad header, discard block
+ *data_size = 0;
+ return buf_size;
+ }
+
+ decode_header(m, header);
+ mp_decode_frame(m, decoded_buf);
+
+ n = MPA_FRAME_SIZE * m->nb_channels;
+ out_size += n * sizeof(OUT_INT);
+ if(s->frames > 1) {
+ /* interleave output data */
+ bp = out_samples + coff[fr];
+ if(m->nb_channels == 1) {
+ for(j = 0; j < n; j++) {
+ *bp = decoded_buf[j];
+ bp += off;
+ }
+ } else {
+ for(j = 0; j < n; j++) {
+ bp[0] = decoded_buf[j++];
+ bp[1] = decoded_buf[j];
+ bp += off;
+ }
+ }
+ }
+ }
+
+ /* update codec info */
+ avctx->sample_rate = s->mp3decctx[0]->sample_rate;
+ avctx->frame_size= buf_size;
+ avctx->bit_rate = 0;
+ for (i = 0; i < s->frames; i++)
+ avctx->bit_rate += s->mp3decctx[i]->bit_rate;
+
+ *data_size = out_size;
+ return buf_size;
+}
+
+
AVCodec mp2_decoder =
{
"mp2",
decode_frame_adu,
CODEC_CAP_PARSE_ONLY,
};
+
+AVCodec mp3on4_decoder =
+{
+ "mp3on4",
+ CODEC_TYPE_AUDIO,
+ CODEC_ID_MP3ON4,
+ sizeof(MP3On4DecodeContext),
+ decode_init_mp3on4,
+ NULL,
+ decode_close_mp3on4,
+ decode_frame_mp3on4,
+ 0
+};