0,0 → 1,115 |
/* |
* 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" |
|
static av_cold int h263_init(AVFormatContext *ctx, int st_index, |
PayloadContext *data) |
{ |
if (st_index < 0) |
return 0; |
ctx->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL; |
return 0; |
} |
|
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; |
|
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 (av_new_packet(pkt, len + startcode)) { |
av_log(ctx, AV_LOG_ERROR, "Out of memory\n"); |
return AVERROR(ENOMEM); |
} |
pkt->stream_index = st->index; |
ptr = pkt->data; |
|
if (startcode) { |
*ptr++ = 0; |
*ptr++ = 0; |
} |
memcpy(ptr, buf, len); |
|
return 0; |
} |
|
RTPDynamicProtocolHandler ff_h263_1998_dynamic_handler = { |
.enc_name = "H263-1998", |
.codec_type = AVMEDIA_TYPE_VIDEO, |
.codec_id = AV_CODEC_ID_H263, |
.init = h263_init, |
.parse_packet = ff_h263_handle_packet, |
}; |
|
RTPDynamicProtocolHandler ff_h263_2000_dynamic_handler = { |
.enc_name = "H263-2000", |
.codec_type = AVMEDIA_TYPE_VIDEO, |
.codec_id = AV_CODEC_ID_H263, |
.init = h263_init, |
.parse_packet = ff_h263_handle_packet, |
}; |