diff options
Diffstat (limited to 'openbsc/src/osmo-bsc_mgcp/mgcp_transcode.c')
| -rw-r--r-- | openbsc/src/osmo-bsc_mgcp/mgcp_transcode.c | 452 |
1 files changed, 452 insertions, 0 deletions
diff --git a/openbsc/src/osmo-bsc_mgcp/mgcp_transcode.c b/openbsc/src/osmo-bsc_mgcp/mgcp_transcode.c new file mode 100644 index 000000000..cadc8769e --- /dev/null +++ b/openbsc/src/osmo-bsc_mgcp/mgcp_transcode.c @@ -0,0 +1,452 @@ +/* + * (C) 2014 by Sysmocom s.f.m.c. GmbH + * (C) 2014 by On-Waves + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * This program 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 Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + */ + +#include <stdlib.h> +#include <string.h> +#include <errno.h> + +#include "bscconfig.h" + +#include "g711common.h" +#include <gsm.h> +#ifdef HAVE_BCG729 +#include <bcg729/decoder.h> +#include <bcg729/encoder.h> +#endif + +#include <openbsc/debug.h> +#include <openbsc/mgcp.h> +#include <openbsc/mgcp_internal.h> + +#include <osmocom/core/talloc.h> + +enum audio_format { + AF_INVALID, + AF_S16, + AF_L16, + AF_GSM, + AF_G729, + AF_PCMA +}; + +struct mgcp_process_rtp_state { + /* decoding */ + enum audio_format src_fmt; + union { + gsm gsm_handle; +#ifdef HAVE_BCG729 + bcg729DecoderChannelContextStruct *g729_dec; +#endif + } src; + size_t src_frame_size; + size_t src_samples_per_frame; + + /* processing */ + + /* encoding */ + enum audio_format dst_fmt; + union { + gsm gsm_handle; +#ifdef HAVE_BCG729 + bcg729EncoderChannelContextStruct *g729_enc; +#endif + } dst; + size_t dst_frame_size; + size_t dst_samples_per_frame; +}; + +static enum audio_format get_audio_format(const struct mgcp_rtp_end *rtp_end) +{ + if (rtp_end->subtype_name) { + if (!strcmp("GSM", rtp_end->subtype_name)) + return AF_GSM; + if (!strcmp("PCMA", rtp_end->subtype_name)) + return AF_PCMA; +#ifdef HAVE_BCG729 + if (!strcmp("G729", rtp_end->subtype_name)) + return AF_G729; +#endif + if (!strcmp("L16", rtp_end->subtype_name)) + return AF_L16; + } + + switch (rtp_end->payload_type) { + case 3 /* GSM */: + return AF_GSM; + case 8 /* PCMA */: + return AF_PCMA; +#ifdef HAVE_BCG729 + case 18 /* G.729 */: + return AF_G729; +#endif + case 11 /* L16 */: + return AF_L16; + default: + return AF_INVALID; + } +} + +static void l16_encode(short *sample, unsigned char *buf, size_t n) +{ + for (; n > 0; --n, ++sample, buf += 2) { + buf[0] = sample[0] >> 8; + buf[1] = sample[0] & 0xff; + } +} + +static void l16_decode(unsigned char *buf, short *sample, size_t n) +{ + for (; n > 0; --n, ++sample, buf += 2) + sample[0] = ((short)buf[0] << 8) | buf[1]; +} + +static void alaw_encode(short *sample, unsigned char *buf, size_t n) +{ + for (; n > 0; --n) + *(buf++) = s16_to_alaw(*(sample++)); +} + +static void alaw_decode(unsigned char *buf, short *sample, size_t n) +{ + for (; n > 0; --n) + *(sample++) = alaw_to_s16(*(buf++)); +} + +static int processing_state_destructor(struct mgcp_process_rtp_state *state) +{ + switch (state->src_fmt) { + case AF_GSM: + if (state->dst.gsm_handle) + gsm_destroy(state->src.gsm_handle); + break; +#ifdef HAVE_BCG729 + case AF_G729: + if (state->src.g729_dec) + closeBcg729DecoderChannel(state->src.g729_dec); + break; +#endif + default: + break; + } + switch (state->dst_fmt) { + case AF_GSM: + if (state->dst.gsm_handle) + gsm_destroy(state->dst.gsm_handle); + break; +#ifdef HAVE_BCG729 + case AF_G729: + if (state->dst.g729_enc) + closeBcg729EncoderChannel(state->dst.g729_enc); + break; +#endif + default: + break; + } + return 0; +} + +int mgcp_transcoding_setup(struct mgcp_endpoint *endp, + struct mgcp_rtp_end *dst_end, + struct mgcp_rtp_end *src_end) +{ + struct mgcp_process_rtp_state *state; + enum audio_format src_fmt, dst_fmt; + + /* cleanup first */ + if (dst_end->rtp_process_data) { + talloc_free(dst_end->rtp_process_data); + dst_end->rtp_process_data = NULL; + } + + if (!src_end) + return 0; + + src_fmt = get_audio_format(src_end); + dst_fmt = get_audio_format(dst_end); + + LOGP(DMGCP, LOGL_ERROR, + "Checking transcoding: %s (%d) -> %s (%d)\n", + src_end->subtype_name, src_end->payload_type, + dst_end->subtype_name, dst_end->payload_type); + + if (src_fmt == AF_INVALID || dst_fmt == AF_INVALID) { + if (!src_end->subtype_name || !dst_end->subtype_name) + /* Not enough info, do nothing */ + return 0; + + if (strcmp(src_end->subtype_name, dst_end->subtype_name) == 0) + /* Nothing to do */ + return 0; + + LOGP(DMGCP, LOGL_ERROR, + "Cannot transcode: %s codec not supported (%s -> %s).\n", + src_fmt != AF_INVALID ? "destination" : "source", + src_end->audio_name, dst_end->audio_name); + return -EINVAL; + } + + if (src_end->rate && dst_end->rate && src_end->rate != dst_end->rate) { + LOGP(DMGCP, LOGL_ERROR, + "Cannot transcode: rate conversion (%d -> %d) not supported.\n", + src_end->rate, dst_end->rate); + return -EINVAL; + } + + state = talloc_zero(endp->tcfg->cfg, struct mgcp_process_rtp_state); + talloc_set_destructor(state, processing_state_destructor); + dst_end->rtp_process_data = state; + + state->src_fmt = src_fmt; + + switch (state->src_fmt) { + case AF_L16: + case AF_S16: + state->src_frame_size = 80 * sizeof(short); + state->src_samples_per_frame = 80; + break; + case AF_GSM: + state->src_frame_size = sizeof(gsm_frame); + state->src_samples_per_frame = 160; + state->src.gsm_handle = gsm_create(); + if (!state->src.gsm_handle) { + LOGP(DMGCP, LOGL_ERROR, + "Failed to initialize GSM decoder.\n"); + return -EINVAL; + } + break; +#ifdef HAVE_BCG729 + case AF_G729: + state->src_frame_size = 10; + state->src_samples_per_frame = 80; + state->src.g729_dec = initBcg729DecoderChannel(); + if (!state->src.g729_dec) { + LOGP(DMGCP, LOGL_ERROR, + "Failed to initialize G.729 decoder.\n"); + return -EINVAL; + } + break; +#endif + case AF_PCMA: + state->src_frame_size = 80; + state->src_samples_per_frame = 80; + break; + default: + break; + } + + state->dst_fmt = dst_fmt; + + switch (state->dst_fmt) { + case AF_L16: + case AF_S16: + state->dst_frame_size = 80*sizeof(short); + state->dst_samples_per_frame = 80; + break; + case AF_GSM: + state->dst_frame_size = sizeof(gsm_frame); + state->dst_samples_per_frame = 160; + state->dst.gsm_handle = gsm_create(); + if (!state->dst.gsm_handle) { + LOGP(DMGCP, LOGL_ERROR, + "Failed to initialize GSM encoder.\n"); + return -EINVAL; + } + break; +#ifdef HAVE_BCG729 + case AF_G729: + state->dst_frame_size = 10; + state->dst_samples_per_frame = 80; + state->dst.g729_enc = initBcg729EncoderChannel(); + if (!state->dst.g729_enc) { + LOGP(DMGCP, LOGL_ERROR, + "Failed to initialize G.729 decoder.\n"); + return -EINVAL; + } + break; +#endif + case AF_PCMA: + state->dst_frame_size = 80; + state->dst_samples_per_frame = 80; + break; + default: + break; + } + + LOGP(DMGCP, LOGL_INFO, + "Initialized RTP processing on: 0x%x " + "conv: %d (%d, %d, %s) -> %d (%d, %d, %s)\n", + ENDPOINT_NUMBER(endp), + src_fmt, src_end->payload_type, src_end->rate, src_end->fmtp_extra, + dst_fmt, dst_end->payload_type, dst_end->rate, dst_end->fmtp_extra); + + return 0; +} + +void mgcp_transcoding_net_downlink_format(struct mgcp_endpoint *endp, + int *payload_type, + const char**audio_name, + const char**fmtp_extra) +{ + struct mgcp_process_rtp_state *state = endp->net_end.rtp_process_data; + if (!state || endp->net_end.payload_type < 0) { + *payload_type = endp->bts_end.payload_type; + *audio_name = endp->bts_end.audio_name; + *fmtp_extra = endp->bts_end.fmtp_extra; + return; + } + + *payload_type = endp->net_end.payload_type; + *fmtp_extra = endp->net_end.fmtp_extra; + *audio_name = endp->net_end.audio_name; +} + + +int mgcp_transcoding_process_rtp(struct mgcp_endpoint *endp, + struct mgcp_rtp_end *dst_end, + char *data, int *len, int buf_size) +{ + struct mgcp_process_rtp_state *state = dst_end->rtp_process_data; + size_t rtp_hdr_size = 12; + char *payload_data = data + rtp_hdr_size; + int payload_len = *len - rtp_hdr_size; + size_t sample_cnt = 0; + size_t sample_idx; + int16_t samples[10*160]; + uint8_t *src = (uint8_t *)payload_data; + uint8_t *dst = (uint8_t *)payload_data; + size_t nbytes = payload_len; + size_t frame_remainder; + + if (!state) + return 0; + + if (state->src_fmt == state->dst_fmt) + return 0; + + /* TODO: check payload type (-> G.711 comfort noise) */ + + /* Decode src into samples */ + while (nbytes >= state->src_frame_size) { + if (sample_cnt + state->src_samples_per_frame > ARRAY_SIZE(samples)) { + LOGP(DMGCP, LOGL_ERROR, + "Sample buffer too small: %d > %d.\n", + sample_cnt + state->src_samples_per_frame, + ARRAY_SIZE(samples)); + return -ENOSPC; + } + switch (state->src_fmt) { + case AF_GSM: + if (gsm_decode(state->src.gsm_handle, + (gsm_byte *)src, samples + sample_cnt) < 0) { + LOGP(DMGCP, LOGL_ERROR, + "Failed to decode GSM.\n"); + return -EINVAL; + } + break; +#ifdef HAVE_BCG729 + case AF_G729: + bcg729Decoder(state->src.g729_dec, src, 0, samples + sample_cnt); + break; +#endif + case AF_PCMA: + alaw_decode(src, samples + sample_cnt, + state->src_samples_per_frame); + break; + case AF_S16: + memmove(samples + sample_cnt, src, + state->src_frame_size); + break; + case AF_L16: + l16_decode(src, samples + sample_cnt, + state->src_samples_per_frame); + break; + default: + break; + } + src += state->src_frame_size; + nbytes -= state->src_frame_size; + sample_cnt += state->src_samples_per_frame; + } + + /* Add silence if necessary */ + frame_remainder = sample_cnt % state->dst_samples_per_frame; + if (frame_remainder) { + size_t silence = state->dst_samples_per_frame - frame_remainder; + if (sample_cnt + silence > ARRAY_SIZE(samples)) { + LOGP(DMGCP, LOGL_ERROR, + "Sample buffer too small for silence: %d > %d.\n", + sample_cnt + silence, + ARRAY_SIZE(samples)); + return -ENOSPC; + } + + while (silence > 0) { + samples[sample_cnt] = 0; + sample_cnt += 1; + silence -= 1; + } + } + + /* Encode samples into dst */ + sample_idx = 0; + nbytes = 0; + while (sample_idx + state->dst_samples_per_frame <= sample_cnt) { + if (nbytes + state->dst_frame_size > buf_size) { + LOGP(DMGCP, LOGL_ERROR, + "Encoding (RTP) buffer too small: %d > %d.\n", + nbytes + state->dst_frame_size, buf_size); + return -ENOSPC; + } + switch (state->dst_fmt) { + case AF_GSM: + gsm_encode(state->dst.gsm_handle, + samples + sample_idx, dst); + break; +#ifdef HAVE_BCG729 + case AF_G729: + bcg729Encoder(state->dst.g729_enc, + samples + sample_idx, dst); + break; +#endif + case AF_PCMA: + alaw_encode(samples + sample_idx, dst, + state->src_samples_per_frame); + break; + case AF_S16: + memmove(dst, samples + sample_idx, state->dst_frame_size); + break; + case AF_L16: + l16_encode(samples + sample_idx, dst, + state->src_samples_per_frame); + break; + default: + break; + } + dst += state->dst_frame_size; + nbytes += state->dst_frame_size; + sample_idx += state->dst_samples_per_frame; + } + + *len = rtp_hdr_size + nbytes; + /* Patch payload type */ + data[1] = (data[1] & 0x80) | (dst_end->payload_type & 0x7f); + + return 0; +} |