1/*
2 * Ogg muxer
3 * Copyright (c) 2007 Baptiste Coudurier <baptiste dot coudurier at free dot fr>
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/crc.h"
23#include "libavcodec/xiph.h"
24#include "libavcodec/bytestream.h"
25#include "libavcodec/flac.h"
26#include "avformat.h"
27#include "internal.h"
28
29typedef struct {
30    int64_t duration;
31    unsigned page_counter;
32    uint8_t *header[3];
33    int header_len[3];
34    /** for theora granule */
35    int kfgshift;
36    int64_t last_kf_pts;
37    int vrev;
38    int eos;
39} OGGStreamContext;
40
41static void ogg_update_checksum(AVFormatContext *s, int64_t crc_offset)
42{
43    int64_t pos = url_ftell(s->pb);
44    uint32_t checksum = get_checksum(s->pb);
45    url_fseek(s->pb, crc_offset, SEEK_SET);
46    put_be32(s->pb, checksum);
47    url_fseek(s->pb, pos, SEEK_SET);
48}
49
50static int ogg_write_page(AVFormatContext *s, const uint8_t *data, int size,
51                          int64_t granule, int stream_index, int flags)
52{
53    OGGStreamContext *oggstream = s->streams[stream_index]->priv_data;
54    int64_t crc_offset;
55    int page_segments, i;
56
57    if (size >= 255*255) {
58        granule = -1;
59        size = 255*255;
60    } else if (oggstream->eos)
61        flags |= 4;
62
63    page_segments = FFMIN((size/255)+!!size, 255);
64
65    init_checksum(s->pb, ff_crc04C11DB7_update, 0);
66    put_tag(s->pb, "OggS");
67    put_byte(s->pb, 0);
68    put_byte(s->pb, flags);
69    put_le64(s->pb, granule);
70    put_le32(s->pb, stream_index);
71    put_le32(s->pb, oggstream->page_counter++);
72    crc_offset = url_ftell(s->pb);
73    put_le32(s->pb, 0); // crc
74    put_byte(s->pb, page_segments);
75    for (i = 0; i < page_segments-1; i++)
76        put_byte(s->pb, 255);
77    if (size) {
78        put_byte(s->pb, size - (page_segments-1)*255);
79        put_buffer(s->pb, data, size);
80    }
81    ogg_update_checksum(s, crc_offset);
82    put_flush_packet(s->pb);
83    return size;
84}
85
86static int ogg_build_flac_headers(AVCodecContext *avctx,
87                                  OGGStreamContext *oggstream, int bitexact)
88{
89    const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
90    enum FLACExtradataFormat format;
91    uint8_t *streaminfo;
92    uint8_t *p;
93    if (!ff_flac_is_extradata_valid(avctx, &format, &streaminfo))
94        return -1;
95    oggstream->header_len[0] = 51;
96    oggstream->header[0] = av_mallocz(51); // per ogg flac specs
97    p = oggstream->header[0];
98    bytestream_put_byte(&p, 0x7F);
99    bytestream_put_buffer(&p, "FLAC", 4);
100    bytestream_put_byte(&p, 1); // major version
101    bytestream_put_byte(&p, 0); // minor version
102    bytestream_put_be16(&p, 1); // headers packets without this one
103    bytestream_put_buffer(&p, "fLaC", 4);
104    bytestream_put_byte(&p, 0x00); // streaminfo
105    bytestream_put_be24(&p, 34);
106    bytestream_put_buffer(&p, streaminfo, FLAC_STREAMINFO_SIZE);
107    oggstream->header_len[1] = 1+3+4+strlen(vendor)+4;
108    oggstream->header[1] = av_mallocz(oggstream->header_len[1]);
109    p = oggstream->header[1];
110    bytestream_put_byte(&p, 0x84); // last metadata block and vorbis comment
111    bytestream_put_be24(&p, oggstream->header_len[1] - 4);
112    bytestream_put_le32(&p, strlen(vendor));
113    bytestream_put_buffer(&p, vendor, strlen(vendor));
114    bytestream_put_le32(&p, 0); // user comment list length
115    return 0;
116}
117
118static int ogg_write_header(AVFormatContext *s)
119{
120    OGGStreamContext *oggstream;
121    int i, j;
122    for (i = 0; i < s->nb_streams; i++) {
123        AVStream *st = s->streams[i];
124        if (st->codec->codec_type == CODEC_TYPE_AUDIO)
125            av_set_pts_info(st, 64, 1, st->codec->sample_rate);
126        else if (st->codec->codec_type == CODEC_TYPE_VIDEO)
127            av_set_pts_info(st, 64, st->codec->time_base.num, st->codec->time_base.den);
128        if (st->codec->codec_id != CODEC_ID_VORBIS &&
129            st->codec->codec_id != CODEC_ID_THEORA &&
130            st->codec->codec_id != CODEC_ID_FLAC) {
131            av_log(s, AV_LOG_ERROR, "Unsupported codec id in stream %d\n", i);
132            return -1;
133        }
134
135        if (!st->codec->extradata || !st->codec->extradata_size) {
136            av_log(s, AV_LOG_ERROR, "No extradata present\n");
137            return -1;
138        }
139        oggstream = av_mallocz(sizeof(*oggstream));
140        st->priv_data = oggstream;
141        if (st->codec->codec_id == CODEC_ID_FLAC) {
142            if (ogg_build_flac_headers(st->codec,
143                                       oggstream, st->codec->flags & CODEC_FLAG_BITEXACT) < 0) {
144                av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");
145                av_freep(&st->priv_data);
146            }
147        } else {
148            if (ff_split_xiph_headers(st->codec->extradata, st->codec->extradata_size,
149                                      st->codec->codec_id == CODEC_ID_VORBIS ? 30 : 42,
150                                      oggstream->header, oggstream->header_len) < 0) {
151                av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");
152                av_freep(&st->priv_data);
153                return -1;
154            }
155            if (st->codec->codec_id == CODEC_ID_THEORA) {
156                /** KFGSHIFT is the width of the less significant section of the granule position
157                    The less significant section is the frame count since the last keyframe */
158                oggstream->kfgshift = ((oggstream->header[0][40]&3)<<3)|(oggstream->header[0][41]>>5);
159                oggstream->vrev = oggstream->header[0][9];
160                av_log(s, AV_LOG_DEBUG, "theora kfgshift %d, vrev %d\n",
161                       oggstream->kfgshift, oggstream->vrev);
162            }
163        }
164    }
165    for (i = 0; i < 3; i++) {
166        for (j = 0; j < s->nb_streams; j++) {
167            AVStream *st = s->streams[j];
168            OGGStreamContext *oggstream = st->priv_data;
169            if (oggstream && oggstream->header_len[i]) {
170                ogg_write_page(s, oggstream->header[i], oggstream->header_len[i],
171                               0, st->index, i ? 0 : 2); // bos
172            }
173        }
174    }
175    return 0;
176}
177
178static int ogg_write_packet(AVFormatContext *s, AVPacket *pkt)
179{
180    AVStream *st = s->streams[pkt->stream_index];
181    OGGStreamContext *oggstream = st->priv_data;
182    uint8_t *ptr = pkt->data;
183    int ret, size = pkt->size;
184    int64_t granule;
185
186    if (st->codec->codec_id == CODEC_ID_THEORA) {
187        int64_t pts = oggstream->vrev < 1 ? pkt->pts : pkt->pts + pkt->duration;
188        int pframe_count;
189        if (pkt->flags & PKT_FLAG_KEY)
190            oggstream->last_kf_pts = pts;
191        pframe_count = pts - oggstream->last_kf_pts;
192        // prevent frame count from overflow if key frame flag is not set
193        if (pframe_count >= (1<<oggstream->kfgshift)) {
194            oggstream->last_kf_pts += pframe_count;
195            pframe_count = 0;
196        }
197        granule = (oggstream->last_kf_pts<<oggstream->kfgshift) | pframe_count;
198    } else
199        granule = pkt->pts + pkt->duration;
200    oggstream->duration = granule;
201    do {
202        ret = ogg_write_page(s, ptr, size, granule, pkt->stream_index, ptr != pkt->data);
203        ptr  += ret; size -= ret;
204    } while (size > 0 || ret == 255*255); // need to output a last nil page
205
206    return 0;
207}
208
209static int ogg_compare_granule(AVFormatContext *s, AVPacket *next, AVPacket *pkt)
210{
211    AVStream *st2 = s->streams[next->stream_index];
212    AVStream *st  = s->streams[pkt ->stream_index];
213
214    int64_t next_granule = av_rescale_q(next->pts + next->duration,
215                                        st2->time_base, AV_TIME_BASE_Q);
216    int64_t cur_granule  = av_rescale_q(pkt ->pts + pkt ->duration,
217                                        st ->time_base, AV_TIME_BASE_Q);
218    return next_granule > cur_granule;
219}
220
221static int ogg_interleave_per_granule(AVFormatContext *s, AVPacket *out, AVPacket *pkt, int flush)
222{
223    AVPacketList *pktl;
224    int stream_count = 0;
225    int streams[MAX_STREAMS] = {0};
226    int interleaved = 0;
227
228    if (pkt) {
229        ff_interleave_add_packet(s, pkt, ogg_compare_granule);
230    }
231
232    pktl = s->packet_buffer;
233    while (pktl) {
234        if (streams[pktl->pkt.stream_index] == 0)
235            stream_count++;
236        streams[pktl->pkt.stream_index]++;
237        // need to buffer at least one packet to set eos flag
238        if (streams[pktl->pkt.stream_index] == 2)
239            interleaved++;
240        pktl = pktl->next;
241    }
242
243    if ((s->nb_streams == stream_count && interleaved == stream_count) ||
244        (flush && stream_count)) {
245        pktl= s->packet_buffer;
246        *out= pktl->pkt;
247        s->packet_buffer = pktl->next;
248        if (flush && streams[out->stream_index] == 1) {
249            OGGStreamContext *ogg = s->streams[out->stream_index]->priv_data;
250            ogg->eos = 1;
251        }
252        av_freep(&pktl);
253        return 1;
254    } else {
255        av_init_packet(out);
256        return 0;
257    }
258}
259
260static int ogg_write_trailer(AVFormatContext *s)
261{
262    int i;
263    for (i = 0; i < s->nb_streams; i++) {
264        AVStream *st = s->streams[i];
265        OGGStreamContext *oggstream = st->priv_data;
266        if (st->codec->codec_id == CODEC_ID_FLAC) {
267            av_free(oggstream->header[0]);
268            av_free(oggstream->header[1]);
269        }
270        av_freep(&st->priv_data);
271    }
272    return 0;
273}
274
275AVOutputFormat ogg_muxer = {
276    "ogg",
277    NULL_IF_CONFIG_SMALL("Ogg"),
278    "application/ogg",
279    "ogg,ogv",
280    0,
281    CODEC_ID_FLAC,
282    CODEC_ID_THEORA,
283    ogg_write_header,
284    ogg_write_packet,
285    ogg_write_trailer,
286    .interleave_packet = ogg_interleave_per_granule,
287};
288