1/*
2 * RTP parser for VC-2 HQ payload format (draft version 1) - experimental
3 * Copyright (c) 2016 Thomas Volkert <thomas@netzeal.de>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "libavutil/intreadwrite.h"
23#include "libavcodec/dirac.h"
24
25#include "avio_internal.h"
26#include "rtpdec_formats.h"
27
28#define RTP_VC2HQ_PL_HEADER_SIZE             4
29
30#define DIRAC_DATA_UNIT_HEADER_SIZE          13
31#define DIRAC_PIC_NR_SIZE                    4
32#define DIRAC_RTP_PCODE_HQ_PIC_FRAGMENT      0xEC
33
34struct PayloadContext {
35    AVIOContext *buf;
36    uint32_t    frame_size;
37    uint32_t    frame_nr;
38    uint32_t    timestamp;
39    uint32_t    last_unit_size;
40    int         seen_sequence_header;
41};
42
43static const uint8_t start_sequence[] = { 'B', 'B', 'C', 'D' };
44
45static void fill_parse_info_header(PayloadContext *pl_ctx, uint8_t *buf,
46                                   uint8_t parse_code, uint32_t data_unit_size)
47{
48    memcpy(buf, start_sequence, sizeof(start_sequence));
49    buf[4]  = parse_code;
50    AV_WB32(&buf[5], data_unit_size);
51    AV_WB32(&buf[9], pl_ctx->last_unit_size);
52
53    pl_ctx->last_unit_size = data_unit_size;
54}
55
56static int vc2hq_handle_sequence_header(PayloadContext *pl_ctx, AVStream *st, AVPacket *pkt,
57                                        const uint8_t *buf, int len)
58{
59    int res;
60    uint32_t size = DIRAC_DATA_UNIT_HEADER_SIZE + len;
61
62    if ((res = av_new_packet(pkt, DIRAC_DATA_UNIT_HEADER_SIZE + len)) < 0)
63        return res;
64
65    fill_parse_info_header(pl_ctx, pkt->data, 0x00, size);
66    /* payload of seq. header */
67    memcpy(pkt->data + DIRAC_DATA_UNIT_HEADER_SIZE, buf, len);
68    pkt->stream_index = st->index;
69
70    pl_ctx->seen_sequence_header = 1;
71
72    return 0;
73}
74
75static int vc2hq_mark_end_of_sequence(PayloadContext *pl_ctx, AVStream *st, AVPacket *pkt)
76{
77    int res;
78    uint32_t size = 0;
79
80    /* create A/V packet */
81    if ((res = av_new_packet(pkt, DIRAC_DATA_UNIT_HEADER_SIZE)) < 0)
82        return res;
83
84    fill_parse_info_header(pl_ctx, pkt->data, 0x10, size);
85    pkt->stream_index = st->index;
86
87    pl_ctx->seen_sequence_header = 0;
88
89    return 0;
90}
91
92static int vc2hq_handle_frame_fragment(AVFormatContext *ctx, PayloadContext *pl_ctx, AVStream *st,
93                                       AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len,
94                                       int flags)
95{
96    int res;
97    uint32_t pic_nr;
98    uint16_t frag_len;
99    uint16_t no_slices;
100
101    /* sanity check for size of input packet: 16 bytes header in any case as minimum */
102    if (len < 16) {
103        av_log(ctx, AV_LOG_ERROR, "Too short RTP/VC2hq packet, got %d bytes\n", len);
104        return AVERROR_INVALIDDATA;
105    }
106
107    pic_nr = AV_RB32(&buf[4]);
108    frag_len = AV_RB16(&buf[12]);
109    no_slices = AV_RB16(&buf[14]);
110
111    if (pl_ctx->buf && pl_ctx->frame_nr != pic_nr) {
112        av_log(ctx, AV_LOG_WARNING, "Dropping buffered RTP/VC2hq packet fragments - non-continuous picture numbers\n");
113        ffio_free_dyn_buf(&pl_ctx->buf);
114    }
115
116    /* transform parameters? */
117    if (no_slices == 0) {
118        if (len < frag_len + 16) {
119            av_log(ctx, AV_LOG_ERROR, "Too short RTP/VC2hq packet, got %d bytes\n", len);
120            return AVERROR_INVALIDDATA;
121        }
122
123        /* start frame buffering with new dynamic buffer */
124        if (!pl_ctx->buf) {
125
126            res = avio_open_dyn_buf(&pl_ctx->buf);
127            if (res < 0)
128                return res;
129
130            /* reserve memory for frame header */
131            res = avio_seek(pl_ctx->buf, DIRAC_DATA_UNIT_HEADER_SIZE + DIRAC_PIC_NR_SIZE, SEEK_SET);
132            if (res < 0)
133                return res;
134
135            pl_ctx->frame_nr = pic_nr;
136            pl_ctx->timestamp = *timestamp;
137            pl_ctx->frame_size = DIRAC_DATA_UNIT_HEADER_SIZE + DIRAC_PIC_NR_SIZE;
138        }
139
140        avio_write(pl_ctx->buf, buf + 16 /* skip pl header */, frag_len);
141        pl_ctx->frame_size += frag_len;
142
143        return AVERROR(EAGAIN);
144    } else {
145        if (len < frag_len + 20) {
146            av_log(ctx, AV_LOG_ERROR, "Too short RTP/VC2hq packet, got %d bytes\n", len);
147            return AVERROR_INVALIDDATA;
148        }
149
150        /* transform parameters were missed, no buffer available */
151        if (!pl_ctx->buf)
152            return AVERROR_INVALIDDATA;
153
154        avio_write(pl_ctx->buf, buf + 20 /* skip pl header */, frag_len);
155        pl_ctx->frame_size += frag_len;
156
157        /* RTP marker bit means: last fragment of current frame was received;
158           otherwise, an additional fragment is needed for the current frame */
159        if (!(flags & RTP_FLAG_MARKER))
160            return AVERROR(EAGAIN);
161    }
162
163    /* close frame buffering and create A/V packet */
164    res = ff_rtp_finalize_packet(pkt, &pl_ctx->buf, st->index);
165    if (res < 0)
166        return res;
167
168    fill_parse_info_header(pl_ctx, pkt->data, DIRAC_PCODE_PICTURE_HQ, pl_ctx->frame_size);
169    AV_WB32(&pkt->data[13], pl_ctx->frame_nr);
170
171    pl_ctx->frame_size = 0;
172
173    return 0;
174}
175
176static int vc2hq_handle_packet(AVFormatContext *ctx, PayloadContext *pl_ctx,
177                               AVStream *st, AVPacket *pkt, uint32_t *timestamp,
178                               const uint8_t *buf, int len, uint16_t seq,
179                               int flags)
180{
181    uint8_t parse_code = 0;
182    int res = 0;
183
184    if (pl_ctx->buf && pl_ctx->timestamp != *timestamp) {
185        av_log(ctx, AV_LOG_WARNING, "Dropping buffered RTP/VC2hq packet fragments - non-continuous timestamps\n");
186        ffio_free_dyn_buf(&pl_ctx->buf);
187        pl_ctx->frame_size = 0;
188    }
189
190    /* sanity check for size of input packet: needed header data as minimum */
191    if (len < RTP_VC2HQ_PL_HEADER_SIZE) {
192        av_log(ctx, AV_LOG_ERROR, "Too short RTP/VC2hq packet, got %d bytes\n", len);
193        return AVERROR_INVALIDDATA;
194    }
195
196    parse_code = buf[3];
197
198    /* wait for next sequence header? */
199    if (pl_ctx->seen_sequence_header || parse_code == DIRAC_PCODE_SEQ_HEADER) {
200        switch(parse_code) {
201        /* sequence header */
202        case DIRAC_PCODE_SEQ_HEADER:
203            res = vc2hq_handle_sequence_header(pl_ctx, st, pkt, buf + RTP_VC2HQ_PL_HEADER_SIZE, len - RTP_VC2HQ_PL_HEADER_SIZE);
204            break;
205        /* end of sequence */
206        case DIRAC_PCODE_END_SEQ:
207            res = vc2hq_mark_end_of_sequence(pl_ctx, st, pkt);
208            break;
209        /* HQ picture fragment */
210        case DIRAC_RTP_PCODE_HQ_PIC_FRAGMENT:
211            res = vc2hq_handle_frame_fragment(ctx, pl_ctx, st, pkt, timestamp, buf, len, flags);
212            break;
213        }
214    }
215
216    return res;
217}
218
219const RTPDynamicProtocolHandler ff_vc2hq_dynamic_handler = {
220    .enc_name         = "VC2",
221    .codec_type       = AVMEDIA_TYPE_VIDEO,
222    .codec_id         = AV_CODEC_ID_DIRAC,
223    .priv_data_size   = sizeof(PayloadContext),
224    .parse_packet     = vc2hq_handle_packet
225};
226