FFmpeg: libavformat/oggenc.c Source File

00001 /*
00002  * Ogg muxer
00003  * Copyright (c) 2007 Baptiste Coudurier <baptiste dot coudurier at free dot fr>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "libavutil/crc.h"
00023 #include "libavcodec/xiph.h"
00024 #include "libavcodec/bytestream.h"
00025 #include "libavcodec/flac.h"
00026 #include "avformat.h"
00027 #include "internal.h"
00028 
00029 typedef struct {
00030     int64_t duration;
00031     unsigned page_counter;
00032     uint8_t *header[3];
00033     int header_len[3];
00035     int kfgshift;
00036     int64_t last_kf_pts;
00037     int vrev;
00038     int eos;
00039 } OGGStreamContext;
00040 
00041 static void ogg_update_checksum(AVFormatContext *s, int64_t crc_offset)
00042 {
00043     int64_t pos = url_ftell(s->pb);
00044     uint32_t checksum = get_checksum(s->pb);
00045     url_fseek(s->pb, crc_offset, SEEK_SET);
00046     put_be32(s->pb, checksum);
00047     url_fseek(s->pb, pos, SEEK_SET);
00048 }
00049 
00050 static int ogg_write_page(AVFormatContext *s, const uint8_t *data, int size,
00051                           int64_t granule, int stream_index, int flags)
00052 {
00053     OGGStreamContext *oggstream = s->streams[stream_index]->priv_data;
00054     int64_t crc_offset;
00055     int page_segments, i;
00056 
00057     if (size >= 255*255) {
00058         granule = -1;
00059         size = 255*255;
00060     } else if (oggstream->eos)
00061         flags |= 4;
00062 
00063     page_segments = FFMIN((size/255)+!!size, 255);
00064 
00065     init_checksum(s->pb, ff_crc04C11DB7_update, 0);
00066     put_tag(s->pb, "OggS");
00067     put_byte(s->pb, 0);
00068     put_byte(s->pb, flags);
00069     put_le64(s->pb, granule);
00070     put_le32(s->pb, stream_index);
00071     put_le32(s->pb, oggstream->page_counter++);
00072     crc_offset = url_ftell(s->pb);
00073     put_le32(s->pb, 0); // crc
00074     put_byte(s->pb, page_segments);
00075     for (i = 0; i < page_segments-1; i++)
00076         put_byte(s->pb, 255);
00077     if (size) {
00078         put_byte(s->pb, size - (page_segments-1)*255);
00079         put_buffer(s->pb, data, size);
00080     }
00081     ogg_update_checksum(s, crc_offset);
00082     put_flush_packet(s->pb);
00083     return size;
00084 }
00085 
00086 static int ogg_build_flac_headers(AVCodecContext *avctx,
00087                                   OGGStreamContext *oggstream, int bitexact)
00088 {
00089     const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
00090     enum FLACExtradataFormat format;
00091     uint8_t *streaminfo;
00092     uint8_t *p;
00093     if (!ff_flac_is_extradata_valid(avctx, &format, &streaminfo))
00094         return -1;
00095     oggstream->header_len[0] = 51;
00096     oggstream->header[0] = av_mallocz(51); // per ogg flac specs
00097     p = oggstream->header[0];
00098     bytestream_put_byte(&p, 0x7F);
00099     bytestream_put_buffer(&p, "FLAC", 4);
00100     bytestream_put_byte(&p, 1); // major version
00101     bytestream_put_byte(&p, 0); // minor version
00102     bytestream_put_be16(&p, 1); // headers packets without this one
00103     bytestream_put_buffer(&p, "fLaC", 4);
00104     bytestream_put_byte(&p, 0x00); // streaminfo
00105     bytestream_put_be24(&p, 34);
00106     bytestream_put_buffer(&p, streaminfo, FLAC_STREAMINFO_SIZE);
00107     oggstream->header_len[1] = 1+3+4+strlen(vendor)+4;
00108     oggstream->header[1] = av_mallocz(oggstream->header_len[1]);
00109     p = oggstream->header[1];
00110     bytestream_put_byte(&p, 0x84); // last metadata block and vorbis comment
00111     bytestream_put_be24(&p, oggstream->header_len[1] - 4);
00112     bytestream_put_le32(&p, strlen(vendor));
00113     bytestream_put_buffer(&p, vendor, strlen(vendor));
00114     bytestream_put_le32(&p, 0); // user comment list length
00115     return 0;
00116 }
00117 
00118 static int ogg_write_header(AVFormatContext *s)
00119 {
00120     OGGStreamContext *oggstream;
00121     int i, j;
00122     for (i = 0; i < s->nb_streams; i++) {
00123         AVStream *st = s->streams[i];
00124         if (st->codec->codec_type == CODEC_TYPE_AUDIO)
00125             av_set_pts_info(st, 64, 1, st->codec->sample_rate);
00126         else if (st->codec->codec_type == CODEC_TYPE_VIDEO)
00127             av_set_pts_info(st, 64, st->codec->time_base.num, st->codec->time_base.den);
00128         if (st->codec->codec_id != CODEC_ID_VORBIS &&
00129             st->codec->codec_id != CODEC_ID_THEORA &&
00130             st->codec->codec_id != CODEC_ID_FLAC) {
00131             av_log(s, AV_LOG_ERROR, "Unsupported codec id in stream %d\n", i);
00132             return -1;
00133         }
00134 
00135         if (!st->codec->extradata || !st->codec->extradata_size) {
00136             av_log(s, AV_LOG_ERROR, "No extradata present\n");
00137             return -1;
00138         }
00139         oggstream = av_mallocz(sizeof(*oggstream));
00140         st->priv_data = oggstream;
00141         if (st->codec->codec_id == CODEC_ID_FLAC) {
00142             if (ogg_build_flac_headers(st->codec,
00143                                        oggstream, st->codec->flags & CODEC_FLAG_BITEXACT) < 0) {
00144                 av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");
00145                 av_freep(&st->priv_data);
00146             }
00147         } else {
00148             if (ff_split_xiph_headers(st->codec->extradata, st->codec->extradata_size,
00149                                       st->codec->codec_id == CODEC_ID_VORBIS ? 30 : 42,
00150                                       oggstream->header, oggstream->header_len) < 0) {
00151                 av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");
00152                 av_freep(&st->priv_data);
00153                 return -1;
00154             }
00155             if (st->codec->codec_id == CODEC_ID_THEORA) {
00158                 oggstream->kfgshift = ((oggstream->header[0][40]&3)<<3)|(oggstream->header[0][41]>>5);
00159                 oggstream->vrev = oggstream->header[0][9];
00160                 av_log(s, AV_LOG_DEBUG, "theora kfgshift %d, vrev %d\n",
00161                        oggstream->kfgshift, oggstream->vrev);
00162             }
00163         }
00164     }
00165     for (i = 0; i < 3; i++) {
00166         for (j = 0; j < s->nb_streams; j++) {
00167             AVStream *st = s->streams[j];
00168             OGGStreamContext *oggstream = st->priv_data;
00169             if (oggstream && oggstream->header_len[i]) {
00170                 ogg_write_page(s, oggstream->header[i], oggstream->header_len[i],
00171                                0, st->index, i ? 0 : 2); // bos
00172             }
00173         }
00174     }
00175     return 0;
00176 }
00177 
00178 static int ogg_write_packet(AVFormatContext *s, AVPacket *pkt)
00179 {
00180     AVStream *st = s->streams[pkt->stream_index];
00181     OGGStreamContext *oggstream = st->priv_data;
00182     uint8_t *ptr = pkt->data;
00183     int ret, size = pkt->size;
00184     int64_t granule;
00185 
00186     if (st->codec->codec_id == CODEC_ID_THEORA) {
00187         int64_t pts = oggstream->vrev < 1 ? pkt->pts : pkt->pts + pkt->duration;
00188         int pframe_count;
00189         if (pkt->flags & PKT_FLAG_KEY)
00190             oggstream->last_kf_pts = pts;
00191         pframe_count = pts - oggstream->last_kf_pts;
00192         // prevent frame count from overflow if key frame flag is not set
00193         if (pframe_count >= (1<<oggstream->kfgshift)) {
00194             oggstream->last_kf_pts += pframe_count;
00195             pframe_count = 0;
00196         }
00197         granule = (oggstream->last_kf_pts<<oggstream->kfgshift) | pframe_count;
00198     } else
00199         granule = pkt->pts + pkt->duration;
00200     oggstream->duration = granule;
00201     do {
00202         ret = ogg_write_page(s, ptr, size, granule, pkt->stream_index, ptr != pkt->data);
00203         ptr  += ret; size -= ret;
00204     } while (size > 0 || ret == 255*255); // need to output a last nil page
00205 
00206     return 0;
00207 }
00208 
00209 static int ogg_compare_granule(AVFormatContext *s, AVPacket *next, AVPacket *pkt)
00210 {
00211     AVStream *st2 = s->streams[next->stream_index];
00212     AVStream *st  = s->streams[pkt ->stream_index];
00213 
00214     int64_t next_granule = av_rescale_q(next->pts + next->duration,
00215                                         st2->time_base, AV_TIME_BASE_Q);
00216     int64_t cur_granule  = av_rescale_q(pkt ->pts + pkt ->duration,
00217                                         st ->time_base, AV_TIME_BASE_Q);
00218     return next_granule > cur_granule;
00219 }
00220 
00221 static int ogg_interleave_per_granule(AVFormatContext *s, AVPacket *out, AVPacket *pkt, int flush)
00222 {
00223     AVPacketList *pktl;
00224     int stream_count = 0;
00225     int streams[MAX_STREAMS] = {0};
00226     int interleaved = 0;
00227 
00228     if (pkt) {
00229         ff_interleave_add_packet(s, pkt, ogg_compare_granule);
00230     }
00231 
00232     pktl = s->packet_buffer;
00233     while (pktl) {
00234         if (streams[pktl->pkt.stream_index] == 0)
00235             stream_count++;
00236         streams[pktl->pkt.stream_index]++;
00237         // need to buffer at least one packet to set eos flag
00238         if (streams[pktl->pkt.stream_index] == 2)
00239             interleaved++;
00240         pktl = pktl->next;
00241     }
00242 
00243     if ((s->nb_streams == stream_count && interleaved == stream_count) ||
00244         (flush && stream_count)) {
00245         pktl= s->packet_buffer;
00246         *out= pktl->pkt;
00247         s->packet_buffer = pktl->next;
00248         if (flush && streams[out->stream_index] == 1) {
00249             OGGStreamContext *ogg = s->streams[out->stream_index]->priv_data;
00250             ogg->eos = 1;
00251         }
00252         av_freep(&pktl);
00253         return 1;
00254     } else {
00255         av_init_packet(out);
00256         return 0;
00257     }
00258 }
00259 
00260 static int ogg_write_trailer(AVFormatContext *s)
00261 {
00262     int i;
00263     for (i = 0; i < s->nb_streams; i++) {
00264         AVStream *st = s->streams[i];
00265         OGGStreamContext *oggstream = st->priv_data;
00266         if (st->codec->codec_id == CODEC_ID_FLAC) {
00267             av_free(oggstream->header[0]);
00268             av_free(oggstream->header[1]);
00269         }
00270         av_freep(&st->priv_data);
00271     }
00272     return 0;
00273 }
00274 
00275 AVOutputFormat ogg_muxer = {
00276     "ogg",
00277     NULL_IF_CONFIG_SMALL("Ogg"),
00278     "application/ogg",
00279     "ogg,ogv",
00280     0,
00281     CODEC_ID_FLAC,
00282     CODEC_ID_THEORA,
00283     ogg_write_header,
00284     ogg_write_packet,
00285     ogg_write_trailer,
00286     .interleave_packet = ogg_interleave_per_granule,
00287 };