yading@11: /*
yading@11:  * RTP packetization for H.263 video
yading@11:  * Copyright (c) 2009 Luca Abeni
yading@11:  * Copyright (c) 2009 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 "avformat.h"
yading@11: #include "rtpenc.h"
yading@11: 
yading@11: const uint8_t *ff_h263_find_resync_marker_reverse(const uint8_t *av_restrict start,
yading@11:                                                   const uint8_t *av_restrict end)
yading@11: {
yading@11:     const uint8_t *p = end - 1;
yading@11:     start += 1; /* Make sure we never return the original start. */
yading@11:     for (; p > start; p -= 2) {
yading@11:         if (!*p) {
yading@11:             if      (!p[ 1] && p[2]) return p;
yading@11:             else if (!p[-1] && p[1]) return p - 1;
yading@11:         }
yading@11:     }
yading@11:     return end;
yading@11: }
yading@11: 
yading@11: /**
yading@11:  * Packetize H.263 frames into RTP packets according to RFC 4629
yading@11:  */
yading@11: void ff_rtp_send_h263(AVFormatContext *s1, const uint8_t *buf1, int size)
yading@11: {
yading@11:     RTPMuxContext *s = s1->priv_data;
yading@11:     int len, max_packet_size;
yading@11:     uint8_t *q;
yading@11: 
yading@11:     max_packet_size = s->max_payload_size;
yading@11: 
yading@11:     while (size > 0) {
yading@11:         q = s->buf;
yading@11:         if (size >= 2 && (buf1[0] == 0) && (buf1[1] == 0)) {
yading@11:             *q++ = 0x04;
yading@11:             buf1 += 2;
yading@11:             size -= 2;
yading@11:         } else {
yading@11:             *q++ = 0;
yading@11:         }
yading@11:         *q++ = 0;
yading@11: 
yading@11:         len = FFMIN(max_packet_size - 2, size);
yading@11: 
yading@11:         /* Look for a better place to split the frame into packets. */
yading@11:         if (len < size) {
yading@11:             const uint8_t *end = ff_h263_find_resync_marker_reverse(buf1,
yading@11:                                                                     buf1 + len);
yading@11:             len = end - buf1;
yading@11:         }
yading@11: 
yading@11:         memcpy(q, buf1, len);
yading@11:         q += len;
yading@11: 
yading@11:         /* 90 KHz time stamp */
yading@11:         s->timestamp = s->cur_timestamp;
yading@11:         ff_rtp_send_data(s1, s->buf, q - s->buf, (len == size));
yading@11: 
yading@11:         buf1 += len;
yading@11:         size -= len;
yading@11:     }
yading@11: }