yading@11: /*
yading@11:  * RTP Depacketization of QCELP/PureVoice, RFC 2658
yading@11:  * Copyright (c) 2010 Martin Storsjo
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include "rtpdec_formats.h"
yading@11: 
yading@11: static const uint8_t frame_sizes[] = {
yading@11:     1, 4, 8, 17, 35
yading@11: };
yading@11: 
yading@11: typedef struct {
yading@11:     int pos;
yading@11:     int size;
yading@11:     /* The largest frame is 35 bytes, only 10 frames are allowed per
yading@11:      * packet, and we return the first one immediately, so allocate
yading@11:      * space for 9 frames */
yading@11:     uint8_t data[35*9];
yading@11: } InterleavePacket;
yading@11: 
yading@11: struct PayloadContext {
yading@11:     int interleave_size;
yading@11:     int interleave_index;
yading@11:     InterleavePacket group[6];
yading@11:     int group_finished;
yading@11: 
yading@11:     /* The maximum packet size, 10 frames of 35 bytes each, and one
yading@11:      * packet header byte. */
yading@11:     uint8_t  next_data[1 + 35*10];
yading@11:     int      next_size;
yading@11:     uint32_t next_timestamp;
yading@11: };
yading@11: 
yading@11: static PayloadContext *qcelp_new_context(void)
yading@11: {
yading@11:     return av_mallocz(sizeof(PayloadContext));
yading@11: }
yading@11: 
yading@11: static void qcelp_free_context(PayloadContext *data)
yading@11: {
yading@11:     av_free(data);
yading@11: }
yading@11: 
yading@11: static int return_stored_frame(AVFormatContext *ctx, PayloadContext *data,
yading@11:                                AVStream *st, AVPacket *pkt, uint32_t *timestamp,
yading@11:                                const uint8_t *buf, int len);
yading@11: 
yading@11: static int store_packet(AVFormatContext *ctx, PayloadContext *data,
yading@11:                         AVStream *st, AVPacket *pkt, uint32_t *timestamp,
yading@11:                         const uint8_t *buf, int len)
yading@11: {
yading@11:     int interleave_size, interleave_index;
yading@11:     int frame_size, ret;
yading@11:     InterleavePacket* ip;
yading@11: 
yading@11:     if (len < 2)
yading@11:         return AVERROR_INVALIDDATA;
yading@11: 
yading@11:     interleave_size  = buf[0] >> 3 & 7;
yading@11:     interleave_index = buf[0]      & 7;
yading@11: 
yading@11:     if (interleave_size > 5) {
yading@11:         av_log(ctx, AV_LOG_ERROR, "Invalid interleave size %d\n",
yading@11:                                    interleave_size);
yading@11:         return AVERROR_INVALIDDATA;
yading@11:     }
yading@11:     if (interleave_index > interleave_size) {
yading@11:         av_log(ctx, AV_LOG_ERROR, "Invalid interleave index %d/%d\n",
yading@11:                                    interleave_index, interleave_size);
yading@11:         return AVERROR_INVALIDDATA;
yading@11:     }
yading@11:     if (interleave_size != data->interleave_size) {
yading@11:         int i;
yading@11:         /* First packet, or changed interleave size */
yading@11:         data->interleave_size = interleave_size;
yading@11:         data->interleave_index = 0;
yading@11:         for (i = 0; i < 6; i++)
yading@11:             data->group[i].size = 0;
yading@11:     }
yading@11: 
yading@11:     if (interleave_index < data->interleave_index) {
yading@11:         /* Wrapped around - missed the last packet of the previous group. */
yading@11:         if (data->group_finished) {
yading@11:             /* No more data in the packets in this interleaving group, just
yading@11:              * start processing the next one */
yading@11:             data->interleave_index = 0;
yading@11:         } else {
yading@11:             /* Stash away the current packet, emit everything we have of the
yading@11:              * previous group. */
yading@11:             for (; data->interleave_index <= interleave_size;
yading@11:                  data->interleave_index++)
yading@11:                 data->group[data->interleave_index].size = 0;
yading@11: 
yading@11:             if (len > sizeof(data->next_data))
yading@11:                 return AVERROR_INVALIDDATA;
yading@11:             memcpy(data->next_data, buf, len);
yading@11:             data->next_size = len;
yading@11:             data->next_timestamp = *timestamp;
yading@11:             *timestamp = RTP_NOTS_VALUE;
yading@11: 
yading@11:             data->interleave_index = 0;
yading@11:             return return_stored_frame(ctx, data, st, pkt, timestamp, buf, len);
yading@11:         }
yading@11:     }
yading@11:     if (interleave_index > data->interleave_index) {
yading@11:         /* We missed a packet */
yading@11:         for (; data->interleave_index < interleave_index;
yading@11:              data->interleave_index++)
yading@11:             data->group[data->interleave_index].size = 0;
yading@11:     }
yading@11:     data->interleave_index = interleave_index;
yading@11: 
yading@11:     if (buf[1] >= FF_ARRAY_ELEMS(frame_sizes))
yading@11:         return AVERROR_INVALIDDATA;
yading@11:     frame_size = frame_sizes[buf[1]];
yading@11:     if (1 + frame_size > len)
yading@11:         return AVERROR_INVALIDDATA;
yading@11: 
yading@11:     if (len - 1 - frame_size > sizeof(data->group[0].data))
yading@11:         return AVERROR_INVALIDDATA;
yading@11: 
yading@11:     if ((ret = av_new_packet(pkt, frame_size)) < 0)
yading@11:         return ret;
yading@11:     memcpy(pkt->data, &buf[1], frame_size);
yading@11:     pkt->stream_index = st->index;
yading@11: 
yading@11:     ip = &data->group[data->interleave_index];
yading@11:     ip->size = len - 1 - frame_size;
yading@11:     ip->pos = 0;
yading@11:     memcpy(ip->data, &buf[1 + frame_size], ip->size);
yading@11:     /* Each packet must contain the same number of frames according to the
yading@11:      * RFC. If there's no data left in this packet, there shouldn't be any
yading@11:      * in any of the other frames in the interleaving group either. */
yading@11:     data->group_finished = ip->size == 0;
yading@11: 
yading@11:     if (interleave_index == interleave_size) {
yading@11:         data->interleave_index = 0;
yading@11:         return !data->group_finished;
yading@11:     } else {
yading@11:         data->interleave_index++;
yading@11:         return 0;
yading@11:     }
yading@11: }
yading@11: 
yading@11: static int return_stored_frame(AVFormatContext *ctx, PayloadContext *data,
yading@11:                                AVStream *st, AVPacket *pkt, uint32_t *timestamp,
yading@11:                                const uint8_t *buf, int len)
yading@11: {
yading@11:     InterleavePacket* ip = &data->group[data->interleave_index];
yading@11:     int frame_size, ret;
yading@11: 
yading@11:     if (data->group_finished && data->interleave_index == 0) {
yading@11:         *timestamp = data->next_timestamp;
yading@11:         ret = store_packet(ctx, data, st, pkt, timestamp, data->next_data,
yading@11:                            data->next_size);
yading@11:         data->next_size = 0;
yading@11:         return ret;
yading@11:     }
yading@11: 
yading@11:     if (ip->size == 0) {
yading@11:         /* No stored data for this interleave block, output an empty packet */
yading@11:         if ((ret = av_new_packet(pkt, 1)) < 0)
yading@11:             return ret;
yading@11:         pkt->data[0] = 0; // Blank - could also be 14, Erasure
yading@11:     } else {
yading@11:         if (ip->pos >= ip->size)
yading@11:             return AVERROR_INVALIDDATA;
yading@11:         if (ip->data[ip->pos] >= FF_ARRAY_ELEMS(frame_sizes))
yading@11:             return AVERROR_INVALIDDATA;
yading@11:         frame_size = frame_sizes[ip->data[ip->pos]];
yading@11:         if (ip->pos + frame_size > ip->size)
yading@11:             return AVERROR_INVALIDDATA;
yading@11: 
yading@11:         if ((ret = av_new_packet(pkt, frame_size)) < 0)
yading@11:             return ret;
yading@11:         memcpy(pkt->data, &ip->data[ip->pos], frame_size);
yading@11: 
yading@11:         ip->pos += frame_size;
yading@11:         data->group_finished = ip->pos >= ip->size;
yading@11:     }
yading@11:     pkt->stream_index = st->index;
yading@11: 
yading@11:     if (data->interleave_index == data->interleave_size) {
yading@11:         data->interleave_index = 0;
yading@11:         if (!data->group_finished)
yading@11:             return 1;
yading@11:         else
yading@11:             return data->next_size > 0;
yading@11:     } else {
yading@11:         data->interleave_index++;
yading@11:         return 1;
yading@11:     }
yading@11: }
yading@11: 
yading@11: static int qcelp_parse_packet(AVFormatContext *ctx, PayloadContext *data,
yading@11:                               AVStream *st, AVPacket *pkt, uint32_t *timestamp,
yading@11:                               const uint8_t *buf, int len, uint16_t seq,
yading@11:                               int flags)
yading@11: {
yading@11:     if (buf)
yading@11:         return store_packet(ctx, data, st, pkt, timestamp, buf, len);
yading@11:     else
yading@11:         return return_stored_frame(ctx, data, st, pkt, timestamp, buf, len);
yading@11: }
yading@11: 
yading@11: RTPDynamicProtocolHandler ff_qcelp_dynamic_handler = {
yading@11:     .enc_name           = "x-Purevoice",
yading@11:     .codec_type         = AVMEDIA_TYPE_AUDIO,
yading@11:     .codec_id           = AV_CODEC_ID_QCELP,
yading@11:     .static_payload_id  = 12,
yading@11:     .alloc              = qcelp_new_context,
yading@11:     .free               = qcelp_free_context,
yading@11:     .parse_packet       = qcelp_parse_packet
yading@11: };