| 1 | /* |
| 2 | * RTP packetization for H.263 video |
| 3 | * Copyright (c) 2009 Luca Abeni |
| 4 | * Copyright (c) 2009 Martin Storsjo |
| 5 | * |
| 6 | * This file is part of FFmpeg. |
| 7 | * |
| 8 | * FFmpeg is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU Lesser General Public |
| 10 | * License as published by the Free Software Foundation; either |
| 11 | * version 2.1 of the License, or (at your option) any later version. |
| 12 | * |
| 13 | * FFmpeg is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | * Lesser General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Lesser General Public |
| 19 | * License along with FFmpeg; if not, write to the Free Software |
| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 21 | */ |
| 22 | |
| 23 | #include "avformat.h" |
| 24 | #include "rtpenc.h" |
| 25 | |
| 26 | const uint8_t *ff_h263_find_resync_marker_reverse(const uint8_t *av_restrict start, |
| 27 | const uint8_t *av_restrict end) |
| 28 | { |
| 29 | const uint8_t *p = end - 1; |
| 30 | start += 1; /* Make sure we never return the original start. */ |
| 31 | for (; p > start; p -= 2) { |
| 32 | if (!*p) { |
| 33 | if (!p[ 1] && p[2]) return p; |
| 34 | else if (!p[-1] && p[1]) return p - 1; |
| 35 | } |
| 36 | } |
| 37 | return end; |
| 38 | } |
| 39 | |
| 40 | /** |
| 41 | * Packetize H.263 frames into RTP packets according to RFC 4629 |
| 42 | */ |
| 43 | void ff_rtp_send_h263(AVFormatContext *s1, const uint8_t *buf1, int size) |
| 44 | { |
| 45 | RTPMuxContext *s = s1->priv_data; |
| 46 | int len, max_packet_size; |
| 47 | uint8_t *q; |
| 48 | |
| 49 | max_packet_size = s->max_payload_size; |
| 50 | |
| 51 | while (size > 0) { |
| 52 | q = s->buf; |
| 53 | if (size >= 2 && (buf1[0] == 0) && (buf1[1] == 0)) { |
| 54 | *q++ = 0x04; |
| 55 | buf1 += 2; |
| 56 | size -= 2; |
| 57 | } else { |
| 58 | *q++ = 0; |
| 59 | } |
| 60 | *q++ = 0; |
| 61 | |
| 62 | len = FFMIN(max_packet_size - 2, size); |
| 63 | |
| 64 | /* Look for a better place to split the frame into packets. */ |
| 65 | if (len < size) { |
| 66 | const uint8_t *end = ff_h263_find_resync_marker_reverse(buf1, |
| 67 | buf1 + len); |
| 68 | len = end - buf1; |
| 69 | } |
| 70 | |
| 71 | memcpy(q, buf1, len); |
| 72 | q += len; |
| 73 | |
| 74 | /* 90 KHz time stamp */ |
| 75 | s->timestamp = s->cur_timestamp; |
| 76 | ff_rtp_send_data(s1, s->buf, q - s->buf, (len == size)); |
| 77 | |
| 78 | buf1 += len; |
| 79 | size -= len; |
| 80 | } |
| 81 | } |