0,0 → 1,215 |
/* |
* RTP H.263 Depacketizer, RFC 2190 |
* Copyright (c) 2012 Martin Storsjo |
* Based on the GStreamer H.263 Depayloder: |
* Copyright 2005 Wim Taymans |
* Copyright 2007 Edward Hervey |
* Copyright 2007 Nokia Corporation |
* Copyright 2007 Collabora Ltd, Philippe Kalaf |
* Copyright 2010 Mark Nauwelaerts |
* |
* 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" |
#include "libavcodec/get_bits.h" |
|
struct PayloadContext { |
AVIOContext *buf; |
uint8_t endbyte; |
int endbyte_bits; |
uint32_t timestamp; |
int newformat; |
}; |
|
static PayloadContext *h263_new_context(void) |
{ |
return av_mallocz(sizeof(PayloadContext)); |
} |
|
static void h263_free_context(PayloadContext *data) |
{ |
if (!data) |
return; |
if (data->buf) { |
uint8_t *p; |
avio_close_dyn_buf(data->buf, &p); |
av_free(p); |
} |
av_free(data); |
} |
|
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; |
} |
|
static int 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) |
{ |
/* Corresponding to header fields in the RFC */ |
int f, p, i, sbit, ebit, src, r; |
int header_size, ret; |
|
if (data->newformat) |
return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf, len, |
seq, flags); |
|
if (data->buf && data->timestamp != *timestamp) { |
/* Dropping old buffered, unfinished data */ |
uint8_t *p; |
avio_close_dyn_buf(data->buf, &p); |
av_free(p); |
data->buf = NULL; |
} |
|
if (len < 4) { |
av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet: %d\n", len); |
return AVERROR_INVALIDDATA; |
} |
|
f = buf[0] & 0x80; |
p = buf[0] & 0x40; |
if (!f) { |
/* Mode A */ |
header_size = 4; |
i = buf[1] & 0x10; |
r = ((buf[1] & 0x01) << 3) | ((buf[2] & 0xe0) >> 5); |
} else if (!p) { |
/* Mode B */ |
header_size = 8; |
if (len < header_size) { |
av_log(ctx, AV_LOG_ERROR, |
"Too short H.263 RTP packet: %d bytes, %d header bytes\n", |
len, header_size); |
return AVERROR_INVALIDDATA; |
} |
r = buf[3] & 0x03; |
i = buf[4] & 0x80; |
} else { |
/* Mode C */ |
header_size = 12; |
if (len < header_size) { |
av_log(ctx, AV_LOG_ERROR, |
"Too short H.263 RTP packet: %d bytes, %d header bytes\n", |
len, header_size); |
return AVERROR_INVALIDDATA; |
} |
r = buf[3] & 0x03; |
i = buf[4] & 0x80; |
} |
sbit = (buf[0] >> 3) & 0x7; |
ebit = buf[0] & 0x7; |
src = (buf[1] & 0xe0) >> 5; |
if (!(buf[0] & 0xf8)) { /* Reserved bits in RFC 2429/4629 are zero */ |
if ((src == 0 || src >= 6) && r) { |
/* Invalid src for this format, and bits that should be zero |
* according to RFC 2190 aren't zero. */ |
av_log(ctx, AV_LOG_WARNING, |
"Interpreting H263 RTP data as RFC 2429/4629 even though " |
"signalled with a static payload type.\n"); |
data->newformat = 1; |
return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf, |
len, seq, flags); |
} |
} |
|
buf += header_size; |
len -= header_size; |
|
if (!data->buf) { |
/* Check the picture start code, only start buffering a new frame |
* if this is correct */ |
if (len > 4 && AV_RB32(buf) >> 10 == 0x20) { |
ret = avio_open_dyn_buf(&data->buf); |
if (ret < 0) |
return ret; |
data->timestamp = *timestamp; |
} else { |
/* Frame not started yet, skipping */ |
return AVERROR(EAGAIN); |
} |
} |
|
if (data->endbyte_bits || sbit) { |
if (data->endbyte_bits == sbit) { |
data->endbyte |= buf[0] & (0xff >> sbit); |
data->endbyte_bits = 0; |
buf++; |
len--; |
avio_w8(data->buf, data->endbyte); |
} else { |
/* Start/end skip bits not matching - missed packets? */ |
GetBitContext gb; |
init_get_bits(&gb, buf, len*8 - ebit); |
skip_bits(&gb, sbit); |
if (data->endbyte_bits) { |
data->endbyte |= get_bits(&gb, 8 - data->endbyte_bits); |
avio_w8(data->buf, data->endbyte); |
} |
while (get_bits_left(&gb) >= 8) |
avio_w8(data->buf, get_bits(&gb, 8)); |
data->endbyte_bits = get_bits_left(&gb); |
if (data->endbyte_bits) |
data->endbyte = get_bits(&gb, data->endbyte_bits) << |
(8 - data->endbyte_bits); |
ebit = 0; |
len = 0; |
} |
} |
if (ebit) { |
if (len > 0) |
avio_write(data->buf, buf, len - 1); |
data->endbyte_bits = 8 - ebit; |
data->endbyte = buf[len - 1] & (0xff << ebit); |
} else { |
avio_write(data->buf, buf, len); |
} |
|
if (!(flags & RTP_FLAG_MARKER)) |
return AVERROR(EAGAIN); |
|
if (data->endbyte_bits) |
avio_w8(data->buf, data->endbyte); |
data->endbyte_bits = 0; |
|
ret = ff_rtp_finalize_packet(pkt, &data->buf, st->index); |
if (ret < 0) |
return ret; |
if (!i) |
pkt->flags |= AV_PKT_FLAG_KEY; |
|
return 0; |
} |
|
RTPDynamicProtocolHandler ff_h263_rfc2190_dynamic_handler = { |
.codec_type = AVMEDIA_TYPE_VIDEO, |
.codec_id = AV_CODEC_ID_H263, |
.init = h263_init, |
.parse_packet = h263_handle_packet, |
.alloc = h263_new_context, |
.free = h263_free_context, |
.static_payload_id = 34, |
}; |