mirror of
https://gitee.com/openharmony/third_party_ffmpeg
synced 2024-11-24 11:49:48 +00:00
109 lines
3.5 KiB
C
109 lines
3.5 KiB
C
/*
|
|
* RTP H.263 Depacketizer, RFC 4629
|
|
* Copyright (c) 2010 Martin Storsjo
|
|
*
|
|
* This file is part of Libav.
|
|
*
|
|
* Libav 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.
|
|
*
|
|
* Libav 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 Libav; 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/intreadwrite.h"
|
|
|
|
static int h263_handle_packet(AVFormatContext *ctx,
|
|
PayloadContext *data,
|
|
AVStream *st,
|
|
AVPacket * pkt,
|
|
uint32_t * timestamp,
|
|
const uint8_t * buf,
|
|
int len, 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 = CODEC_ID_H263,
|
|
.parse_packet = h263_handle_packet,
|
|
};
|
|
|
|
RTPDynamicProtocolHandler ff_h263_2000_dynamic_handler = {
|
|
.enc_name = "H263-2000",
|
|
.codec_type = AVMEDIA_TYPE_VIDEO,
|
|
.codec_id = CODEC_ID_H263,
|
|
.parse_packet = h263_handle_packet,
|
|
};
|
|
|