| /* |
| * RTP H.263 Depacketizer, RFC 4629 |
| * Copyright (c) 2010 Martin Storsjo |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg 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 |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include "avformat.h" |
| #include "rtpdec_formats.h" |
| #include "libavutil/attributes.h" |
| #include "libavutil/intreadwrite.h" |
| |
| int ff_h263_handle_packet(AVFormatContext *ctx, PayloadContext *data, |
| AVStream *st, AVPacket *pkt, uint32_t *timestamp, |
| const uint8_t *buf, int len, uint16_t seq, int flags) |
| { |
| uint8_t *ptr; |
| uint16_t header; |
| int startcode, vrc, picture_header, ret; |
| |
| if (len < 2) { |
| av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet\n"); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| /* Decode the 16 bit H.263+ payload header, as described in section |
| * 5.1 of RFC 4629. The fields of this header are: |
| * - 5 reserved bits, should be ignored. |
| * - One bit (P, startcode), indicating a picture start, picture segment |
| * start or video sequence end. If set, two zero bytes should be |
| * prepended to the payload. |
| * - One bit (V, vrc), indicating the presence of an 8 bit Video |
| * Redundancy Coding field after this 16 bit header. |
| * - 6 bits (PLEN, picture_header), the length (in bytes) of an extra |
| * picture header, following the VRC field. |
| * - 3 bits (PEBIT), the number of bits to ignore of the last byte |
| * of the extra picture header. (Not used at the moment.) |
| */ |
| header = AV_RB16(buf); |
| startcode = (header & 0x0400) >> 9; |
| vrc = header & 0x0200; |
| picture_header = (header & 0x01f8) >> 3; |
| buf += 2; |
| len -= 2; |
| |
| if (vrc) { |
| /* Skip VRC header if present, not used at the moment. */ |
| buf += 1; |
| len -= 1; |
| } |
| if (picture_header) { |
| /* Skip extra picture header if present, not used at the moment. */ |
| buf += picture_header; |
| len -= picture_header; |
| } |
| |
| if (len < 0) { |
| av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet\n"); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| if ((ret = av_new_packet(pkt, len + startcode)) < 0) { |
| av_log(ctx, AV_LOG_ERROR, "Out of memory\n"); |
| return ret; |
| } |
| pkt->stream_index = st->index; |
| ptr = pkt->data; |
| |
| if (startcode) { |
| *ptr++ = 0; |
| *ptr++ = 0; |
| } |
| memcpy(ptr, buf, len); |
| |
| return 0; |
| } |
| |
| const RTPDynamicProtocolHandler ff_h263_1998_dynamic_handler = { |
| .enc_name = "H263-1998", |
| .codec_type = AVMEDIA_TYPE_VIDEO, |
| .codec_id = AV_CODEC_ID_H263, |
| .need_parsing = AVSTREAM_PARSE_FULL, |
| .parse_packet = ff_h263_handle_packet, |
| }; |
| |
| const RTPDynamicProtocolHandler ff_h263_2000_dynamic_handler = { |
| .enc_name = "H263-2000", |
| .codec_type = AVMEDIA_TYPE_VIDEO, |
| .codec_id = AV_CODEC_ID_H263, |
| .need_parsing = AVSTREAM_PARSE_FULL, |
| .parse_packet = ff_h263_handle_packet, |
| }; |