1/*
2 * Live smooth streaming fragmenter
3 * Copyright (c) 2012 Martin Storsjo
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 "config.h"
23#include <float.h>
24#if HAVE_UNISTD_H
25#include <unistd.h>
26#endif
27
28#include "avformat.h"
29#include "internal.h"
30#include "os_support.h"
31#include "avc.h"
32#include "url.h"
33#include "isom.h"
34
35#include "libavutil/opt.h"
36#include "libavutil/avstring.h"
37#include "libavutil/mathematics.h"
38#include "libavutil/intreadwrite.h"
39
40typedef struct {
41    char file[1024];
42    char infofile[1024];
43    int64_t start_time, duration;
44    int n;
45    int64_t start_pos, size;
46} Fragment;
47
48typedef struct {
49    AVFormatContext *ctx;
50    int ctx_inited;
51    char dirname[1024];
52    uint8_t iobuf[32768];
53    URLContext *out;  // Current output stream where all output is written
54    URLContext *out2; // Auxiliary output stream where all output is also written
55    URLContext *tail_out; // The actual main output stream, if we're currently seeked back to write elsewhere
56    int64_t tail_pos, cur_pos, cur_start_pos;
57    int packets_written;
58    const char *stream_type_tag;
59    int nb_fragments, fragments_size, fragment_index;
60    Fragment **fragments;
61
62    const char *fourcc;
63    char *private_str;
64    int packet_size;
65    int audio_tag;
66} OutputStream;
67
68typedef struct {
69    const AVClass *class;  /* Class for private options. */
70    int window_size;
71    int extra_window_size;
72    int lookahead_count;
73    int min_frag_duration;
74    int remove_at_exit;
75    OutputStream *streams;
76    int has_video, has_audio;
77    int nb_fragments;
78} SmoothStreamingContext;
79
80static int ism_write(void *opaque, uint8_t *buf, int buf_size)
81{
82    OutputStream *os = opaque;
83    if (os->out)
84        ffurl_write(os->out, buf, buf_size);
85    if (os->out2)
86        ffurl_write(os->out2, buf, buf_size);
87    os->cur_pos += buf_size;
88    if (os->cur_pos >= os->tail_pos)
89        os->tail_pos = os->cur_pos;
90    return buf_size;
91}
92
93static int64_t ism_seek(void *opaque, int64_t offset, int whence)
94{
95    OutputStream *os = opaque;
96    int i;
97    if (whence != SEEK_SET)
98        return AVERROR(ENOSYS);
99    if (os->tail_out) {
100        if (os->out) {
101            ffurl_close(os->out);
102        }
103        if (os->out2) {
104            ffurl_close(os->out2);
105        }
106        os->out = os->tail_out;
107        os->out2 = NULL;
108        os->tail_out = NULL;
109    }
110    if (offset >= os->cur_start_pos) {
111        if (os->out)
112            ffurl_seek(os->out, offset - os->cur_start_pos, SEEK_SET);
113        os->cur_pos = offset;
114        return offset;
115    }
116    for (i = os->nb_fragments - 1; i >= 0; i--) {
117        Fragment *frag = os->fragments[i];
118        if (offset >= frag->start_pos && offset < frag->start_pos + frag->size) {
119            int ret;
120            AVDictionary *opts = NULL;
121            os->tail_out = os->out;
122            av_dict_set(&opts, "truncate", "0", 0);
123            ret = ffurl_open(&os->out, frag->file, AVIO_FLAG_READ_WRITE, &os->ctx->interrupt_callback, &opts);
124            av_dict_free(&opts);
125            if (ret < 0) {
126                os->out = os->tail_out;
127                os->tail_out = NULL;
128                return ret;
129            }
130            av_dict_set(&opts, "truncate", "0", 0);
131            ffurl_open(&os->out2, frag->infofile, AVIO_FLAG_READ_WRITE, &os->ctx->interrupt_callback, &opts);
132            av_dict_free(&opts);
133            ffurl_seek(os->out, offset - frag->start_pos, SEEK_SET);
134            if (os->out2)
135                ffurl_seek(os->out2, offset - frag->start_pos, SEEK_SET);
136            os->cur_pos = offset;
137            return offset;
138        }
139    }
140    return AVERROR(EIO);
141}
142
143static void get_private_data(OutputStream *os)
144{
145    AVCodecContext *codec = os->ctx->streams[0]->codec;
146    uint8_t *ptr = codec->extradata;
147    int size = codec->extradata_size;
148    int i;
149    if (codec->codec_id == AV_CODEC_ID_H264) {
150        ff_avc_write_annexb_extradata(ptr, &ptr, &size);
151        if (!ptr)
152            ptr = codec->extradata;
153    }
154    if (!ptr)
155        return;
156    os->private_str = av_mallocz(2*size + 1);
157    if (!os->private_str)
158        goto fail;
159    for (i = 0; i < size; i++)
160        snprintf(&os->private_str[2*i], 3, "%02x", ptr[i]);
161fail:
162    if (ptr != codec->extradata)
163        av_free(ptr);
164}
165
166static void ism_free(AVFormatContext *s)
167{
168    SmoothStreamingContext *c = s->priv_data;
169    int i, j;
170    if (!c->streams)
171        return;
172    for (i = 0; i < s->nb_streams; i++) {
173        OutputStream *os = &c->streams[i];
174        ffurl_close(os->out);
175        ffurl_close(os->out2);
176        ffurl_close(os->tail_out);
177        os->out = os->out2 = os->tail_out = NULL;
178        if (os->ctx && os->ctx_inited)
179            av_write_trailer(os->ctx);
180        if (os->ctx && os->ctx->pb)
181            av_free(os->ctx->pb);
182        if (os->ctx)
183            avformat_free_context(os->ctx);
184        av_free(os->private_str);
185        for (j = 0; j < os->nb_fragments; j++)
186            av_free(os->fragments[j]);
187        av_free(os->fragments);
188    }
189    av_freep(&c->streams);
190}
191
192static void output_chunk_list(OutputStream *os, AVIOContext *out, int final, int skip, int window_size)
193{
194    int removed = 0, i, start = 0;
195    if (os->nb_fragments <= 0)
196        return;
197    if (os->fragments[0]->n > 0)
198        removed = 1;
199    if (final)
200        skip = 0;
201    if (window_size)
202        start = FFMAX(os->nb_fragments - skip - window_size, 0);
203    for (i = start; i < os->nb_fragments - skip; i++) {
204        Fragment *frag = os->fragments[i];
205        if (!final || removed)
206            avio_printf(out, "<c t=\"%"PRIu64"\" d=\"%"PRIu64"\" />\n", frag->start_time, frag->duration);
207        else
208            avio_printf(out, "<c n=\"%d\" d=\"%"PRIu64"\" />\n", frag->n, frag->duration);
209    }
210}
211
212static int write_manifest(AVFormatContext *s, int final)
213{
214    SmoothStreamingContext *c = s->priv_data;
215    AVIOContext *out;
216    char filename[1024], temp_filename[1024];
217    int ret, i, video_chunks = 0, audio_chunks = 0, video_streams = 0, audio_streams = 0;
218    int64_t duration = 0;
219
220    snprintf(filename, sizeof(filename), "%s/Manifest", s->filename);
221    snprintf(temp_filename, sizeof(temp_filename), "%s/Manifest.tmp", s->filename);
222    ret = avio_open2(&out, temp_filename, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL);
223    if (ret < 0) {
224        av_log(s, AV_LOG_ERROR, "Unable to open %s for writing\n", temp_filename);
225        return ret;
226    }
227    avio_printf(out, "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
228    for (i = 0; i < s->nb_streams; i++) {
229        OutputStream *os = &c->streams[i];
230        if (os->nb_fragments > 0) {
231            Fragment *last = os->fragments[os->nb_fragments - 1];
232            duration = last->start_time + last->duration;
233        }
234        if (s->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
235            video_chunks = os->nb_fragments;
236            video_streams++;
237        } else {
238            audio_chunks = os->nb_fragments;
239            audio_streams++;
240        }
241    }
242    if (!final) {
243        duration = 0;
244        video_chunks = audio_chunks = 0;
245    }
246    if (c->window_size) {
247        video_chunks = FFMIN(video_chunks, c->window_size);
248        audio_chunks = FFMIN(audio_chunks, c->window_size);
249    }
250    avio_printf(out, "<SmoothStreamingMedia MajorVersion=\"2\" MinorVersion=\"0\" Duration=\"%"PRIu64"\"", duration);
251    if (!final)
252        avio_printf(out, " IsLive=\"true\" LookAheadFragmentCount=\"%d\" DVRWindowLength=\"0\"", c->lookahead_count);
253    avio_printf(out, ">\n");
254    if (c->has_video) {
255        int last = -1, index = 0;
256        avio_printf(out, "<StreamIndex Type=\"video\" QualityLevels=\"%d\" Chunks=\"%d\" Url=\"QualityLevels({bitrate})/Fragments(video={start time})\">\n", video_streams, video_chunks);
257        for (i = 0; i < s->nb_streams; i++) {
258            OutputStream *os = &c->streams[i];
259            if (s->streams[i]->codec->codec_type != AVMEDIA_TYPE_VIDEO)
260                continue;
261            last = i;
262            avio_printf(out, "<QualityLevel Index=\"%d\" Bitrate=\"%d\" FourCC=\"%s\" MaxWidth=\"%d\" MaxHeight=\"%d\" CodecPrivateData=\"%s\" />\n", index, s->streams[i]->codec->bit_rate, os->fourcc, s->streams[i]->codec->width, s->streams[i]->codec->height, os->private_str);
263            index++;
264        }
265        output_chunk_list(&c->streams[last], out, final, c->lookahead_count, c->window_size);
266        avio_printf(out, "</StreamIndex>\n");
267    }
268    if (c->has_audio) {
269        int last = -1, index = 0;
270        avio_printf(out, "<StreamIndex Type=\"audio\" QualityLevels=\"%d\" Chunks=\"%d\" Url=\"QualityLevels({bitrate})/Fragments(audio={start time})\">\n", audio_streams, audio_chunks);
271        for (i = 0; i < s->nb_streams; i++) {
272            OutputStream *os = &c->streams[i];
273            if (s->streams[i]->codec->codec_type != AVMEDIA_TYPE_AUDIO)
274                continue;
275            last = i;
276            avio_printf(out, "<QualityLevel Index=\"%d\" Bitrate=\"%d\" FourCC=\"%s\" SamplingRate=\"%d\" Channels=\"%d\" BitsPerSample=\"16\" PacketSize=\"%d\" AudioTag=\"%d\" CodecPrivateData=\"%s\" />\n", index, s->streams[i]->codec->bit_rate, os->fourcc, s->streams[i]->codec->sample_rate, s->streams[i]->codec->channels, os->packet_size, os->audio_tag, os->private_str);
277            index++;
278        }
279        output_chunk_list(&c->streams[last], out, final, c->lookahead_count, c->window_size);
280        avio_printf(out, "</StreamIndex>\n");
281    }
282    avio_printf(out, "</SmoothStreamingMedia>\n");
283    avio_flush(out);
284    avio_close(out);
285    rename(temp_filename, filename);
286    return 0;
287}
288
289static int ism_write_header(AVFormatContext *s)
290{
291    SmoothStreamingContext *c = s->priv_data;
292    int ret = 0, i;
293    AVOutputFormat *oformat;
294
295    if (mkdir(s->filename, 0777) < 0) {
296        av_log(s, AV_LOG_ERROR, "mkdir failed\n");
297        ret = AVERROR(errno);
298        goto fail;
299    }
300
301    oformat = av_guess_format("ismv", NULL, NULL);
302    if (!oformat) {
303        ret = AVERROR_MUXER_NOT_FOUND;
304        goto fail;
305    }
306
307    c->streams = av_mallocz_array(s->nb_streams, sizeof(*c->streams));
308    if (!c->streams) {
309        ret = AVERROR(ENOMEM);
310        goto fail;
311    }
312
313    for (i = 0; i < s->nb_streams; i++) {
314        OutputStream *os = &c->streams[i];
315        AVFormatContext *ctx;
316        AVStream *st;
317        AVDictionary *opts = NULL;
318        char buf[10];
319
320        if (!s->streams[i]->codec->bit_rate) {
321            av_log(s, AV_LOG_ERROR, "No bit rate set for stream %d\n", i);
322            ret = AVERROR(EINVAL);
323            goto fail;
324        }
325        snprintf(os->dirname, sizeof(os->dirname), "%s/QualityLevels(%d)", s->filename, s->streams[i]->codec->bit_rate);
326        if (mkdir(os->dirname, 0777) < 0) {
327            ret = AVERROR(errno);
328            av_log(s, AV_LOG_ERROR, "mkdir failed\n");
329            goto fail;
330        }
331
332        ctx = avformat_alloc_context();
333        if (!ctx) {
334            ret = AVERROR(ENOMEM);
335            goto fail;
336        }
337        os->ctx = ctx;
338        ctx->oformat = oformat;
339        ctx->interrupt_callback = s->interrupt_callback;
340
341        if (!(st = avformat_new_stream(ctx, NULL))) {
342            ret = AVERROR(ENOMEM);
343            goto fail;
344        }
345        avcodec_copy_context(st->codec, s->streams[i]->codec);
346        st->sample_aspect_ratio = s->streams[i]->sample_aspect_ratio;
347
348        ctx->pb = avio_alloc_context(os->iobuf, sizeof(os->iobuf), AVIO_FLAG_WRITE, os, NULL, ism_write, ism_seek);
349        if (!ctx->pb) {
350            ret = AVERROR(ENOMEM);
351            goto fail;
352        }
353
354        snprintf(buf, sizeof(buf), "%d", c->lookahead_count);
355        av_dict_set(&opts, "ism_lookahead", buf, 0);
356        av_dict_set(&opts, "movflags", "frag_custom", 0);
357        if ((ret = avformat_write_header(ctx, &opts)) < 0) {
358             goto fail;
359        }
360        os->ctx_inited = 1;
361        avio_flush(ctx->pb);
362        av_dict_free(&opts);
363        s->streams[i]->time_base = st->time_base;
364        if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
365            c->has_video = 1;
366            os->stream_type_tag = "video";
367            if (st->codec->codec_id == AV_CODEC_ID_H264) {
368                os->fourcc = "H264";
369            } else if (st->codec->codec_id == AV_CODEC_ID_VC1) {
370                os->fourcc = "WVC1";
371            } else {
372                av_log(s, AV_LOG_ERROR, "Unsupported video codec\n");
373                ret = AVERROR(EINVAL);
374                goto fail;
375            }
376        } else {
377            c->has_audio = 1;
378            os->stream_type_tag = "audio";
379            if (st->codec->codec_id == AV_CODEC_ID_AAC) {
380                os->fourcc = "AACL";
381                os->audio_tag = 0xff;
382            } else if (st->codec->codec_id == AV_CODEC_ID_WMAPRO) {
383                os->fourcc = "WMAP";
384                os->audio_tag = 0x0162;
385            } else {
386                av_log(s, AV_LOG_ERROR, "Unsupported audio codec\n");
387                ret = AVERROR(EINVAL);
388                goto fail;
389            }
390            os->packet_size = st->codec->block_align ? st->codec->block_align : 4;
391        }
392        get_private_data(os);
393    }
394
395    if (!c->has_video && c->min_frag_duration <= 0) {
396        av_log(s, AV_LOG_WARNING, "no video stream and no min frag duration set\n");
397        ret = AVERROR(EINVAL);
398    }
399    ret = write_manifest(s, 0);
400
401fail:
402    if (ret)
403        ism_free(s);
404    return ret;
405}
406
407static int parse_fragment(AVFormatContext *s, const char *filename, int64_t *start_ts, int64_t *duration, int64_t *moof_size, int64_t size)
408{
409    AVIOContext *in;
410    int ret;
411    uint32_t len;
412    if ((ret = avio_open2(&in, filename, AVIO_FLAG_READ, &s->interrupt_callback, NULL)) < 0)
413        return ret;
414    ret = AVERROR(EIO);
415    *moof_size = avio_rb32(in);
416    if (*moof_size < 8 || *moof_size > size)
417        goto fail;
418    if (avio_rl32(in) != MKTAG('m','o','o','f'))
419        goto fail;
420    len = avio_rb32(in);
421    if (len > *moof_size)
422        goto fail;
423    if (avio_rl32(in) != MKTAG('m','f','h','d'))
424        goto fail;
425    avio_seek(in, len - 8, SEEK_CUR);
426    avio_rb32(in); /* traf size */
427    if (avio_rl32(in) != MKTAG('t','r','a','f'))
428        goto fail;
429    while (avio_tell(in) < *moof_size) {
430        uint32_t len = avio_rb32(in);
431        uint32_t tag = avio_rl32(in);
432        int64_t end = avio_tell(in) + len - 8;
433        if (len < 8 || len >= *moof_size)
434            goto fail;
435        if (tag == MKTAG('u','u','i','d')) {
436            static const uint8_t tfxd[] = {
437                0x6d, 0x1d, 0x9b, 0x05, 0x42, 0xd5, 0x44, 0xe6,
438                0x80, 0xe2, 0x14, 0x1d, 0xaf, 0xf7, 0x57, 0xb2
439            };
440            uint8_t uuid[16];
441            avio_read(in, uuid, 16);
442            if (!memcmp(uuid, tfxd, 16) && len >= 8 + 16 + 4 + 16) {
443                avio_seek(in, 4, SEEK_CUR);
444                *start_ts = avio_rb64(in);
445                *duration = avio_rb64(in);
446                ret = 0;
447                break;
448            }
449        }
450        avio_seek(in, end, SEEK_SET);
451    }
452fail:
453    avio_close(in);
454    return ret;
455}
456
457static int add_fragment(OutputStream *os, const char *file, const char *infofile, int64_t start_time, int64_t duration, int64_t start_pos, int64_t size)
458{
459    int err;
460    Fragment *frag;
461    if (os->nb_fragments >= os->fragments_size) {
462        os->fragments_size = (os->fragments_size + 1) * 2;
463        if ((err = av_reallocp(&os->fragments, sizeof(*os->fragments) *
464                               os->fragments_size)) < 0) {
465            os->fragments_size = 0;
466            os->nb_fragments = 0;
467            return err;
468        }
469    }
470    frag = av_mallocz(sizeof(*frag));
471    if (!frag)
472        return AVERROR(ENOMEM);
473    av_strlcpy(frag->file, file, sizeof(frag->file));
474    av_strlcpy(frag->infofile, infofile, sizeof(frag->infofile));
475    frag->start_time = start_time;
476    frag->duration = duration;
477    frag->start_pos = start_pos;
478    frag->size = size;
479    frag->n = os->fragment_index;
480    os->fragments[os->nb_fragments++] = frag;
481    os->fragment_index++;
482    return 0;
483}
484
485static int copy_moof(AVFormatContext *s, const char* infile, const char *outfile, int64_t size)
486{
487    AVIOContext *in, *out;
488    int ret = 0;
489    if ((ret = avio_open2(&in, infile, AVIO_FLAG_READ, &s->interrupt_callback, NULL)) < 0)
490        return ret;
491    if ((ret = avio_open2(&out, outfile, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL)) < 0) {
492        avio_close(in);
493        return ret;
494    }
495    while (size > 0) {
496        uint8_t buf[8192];
497        int n = FFMIN(size, sizeof(buf));
498        n = avio_read(in, buf, n);
499        if (n <= 0) {
500            ret = AVERROR(EIO);
501            break;
502        }
503        avio_write(out, buf, n);
504        size -= n;
505    }
506    avio_flush(out);
507    avio_close(out);
508    avio_close(in);
509    return ret;
510}
511
512static int ism_flush(AVFormatContext *s, int final)
513{
514    SmoothStreamingContext *c = s->priv_data;
515    int i, ret = 0;
516
517    for (i = 0; i < s->nb_streams; i++) {
518        OutputStream *os = &c->streams[i];
519        char filename[1024], target_filename[1024], header_filename[1024];
520        int64_t start_pos = os->tail_pos, size;
521        int64_t start_ts, duration, moof_size;
522        if (!os->packets_written)
523            continue;
524
525        snprintf(filename, sizeof(filename), "%s/temp", os->dirname);
526        ret = ffurl_open(&os->out, filename, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL);
527        if (ret < 0)
528            break;
529        os->cur_start_pos = os->tail_pos;
530        av_write_frame(os->ctx, NULL);
531        avio_flush(os->ctx->pb);
532        os->packets_written = 0;
533        if (!os->out || os->tail_out)
534            return AVERROR(EIO);
535
536        ffurl_close(os->out);
537        os->out = NULL;
538        size = os->tail_pos - start_pos;
539        if ((ret = parse_fragment(s, filename, &start_ts, &duration, &moof_size, size)) < 0)
540            break;
541        snprintf(header_filename, sizeof(header_filename), "%s/FragmentInfo(%s=%"PRIu64")", os->dirname, os->stream_type_tag, start_ts);
542        snprintf(target_filename, sizeof(target_filename), "%s/Fragments(%s=%"PRIu64")", os->dirname, os->stream_type_tag, start_ts);
543        copy_moof(s, filename, header_filename, moof_size);
544        rename(filename, target_filename);
545        add_fragment(os, target_filename, header_filename, start_ts, duration, start_pos, size);
546    }
547
548    if (c->window_size || (final && c->remove_at_exit)) {
549        for (i = 0; i < s->nb_streams; i++) {
550            OutputStream *os = &c->streams[i];
551            int j;
552            int remove = os->nb_fragments - c->window_size - c->extra_window_size - c->lookahead_count;
553            if (final && c->remove_at_exit)
554                remove = os->nb_fragments;
555            if (remove > 0) {
556                for (j = 0; j < remove; j++) {
557                    unlink(os->fragments[j]->file);
558                    unlink(os->fragments[j]->infofile);
559                    av_free(os->fragments[j]);
560                }
561                os->nb_fragments -= remove;
562                memmove(os->fragments, os->fragments + remove, os->nb_fragments * sizeof(*os->fragments));
563            }
564            if (final && c->remove_at_exit)
565                rmdir(os->dirname);
566        }
567    }
568
569    if (ret >= 0)
570        ret = write_manifest(s, final);
571    return ret;
572}
573
574static int ism_write_packet(AVFormatContext *s, AVPacket *pkt)
575{
576    SmoothStreamingContext *c = s->priv_data;
577    AVStream *st = s->streams[pkt->stream_index];
578    OutputStream *os = &c->streams[pkt->stream_index];
579    int64_t end_dts = (c->nb_fragments + 1LL) * c->min_frag_duration;
580    int ret;
581
582    if (st->first_dts == AV_NOPTS_VALUE)
583        st->first_dts = pkt->dts;
584
585    if ((!c->has_video || st->codec->codec_type == AVMEDIA_TYPE_VIDEO) &&
586        av_compare_ts(pkt->dts - st->first_dts, st->time_base,
587                      end_dts, AV_TIME_BASE_Q) >= 0 &&
588        pkt->flags & AV_PKT_FLAG_KEY && os->packets_written) {
589
590        if ((ret = ism_flush(s, 0)) < 0)
591            return ret;
592        c->nb_fragments++;
593    }
594
595    os->packets_written++;
596    return ff_write_chained(os->ctx, 0, pkt, s);
597}
598
599static int ism_write_trailer(AVFormatContext *s)
600{
601    SmoothStreamingContext *c = s->priv_data;
602    ism_flush(s, 1);
603
604    if (c->remove_at_exit) {
605        char filename[1024];
606        snprintf(filename, sizeof(filename), "%s/Manifest", s->filename);
607        unlink(filename);
608        rmdir(s->filename);
609    }
610
611    ism_free(s);
612    return 0;
613}
614
615#define OFFSET(x) offsetof(SmoothStreamingContext, x)
616#define E AV_OPT_FLAG_ENCODING_PARAM
617static const AVOption options[] = {
618    { "window_size", "number of fragments kept in the manifest", OFFSET(window_size), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, E },
619    { "extra_window_size", "number of fragments kept outside of the manifest before removing from disk", OFFSET(extra_window_size), AV_OPT_TYPE_INT, { .i64 = 5 }, 0, INT_MAX, E },
620    { "lookahead_count", "number of lookahead fragments", OFFSET(lookahead_count), AV_OPT_TYPE_INT, { .i64 = 2 }, 0, INT_MAX, E },
621    { "min_frag_duration", "minimum fragment duration (in microseconds)", OFFSET(min_frag_duration), AV_OPT_TYPE_INT64, { .i64 = 5000000 }, 0, INT_MAX, E },
622    { "remove_at_exit", "remove all fragments when finished", OFFSET(remove_at_exit), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, E },
623    { NULL },
624};
625
626static const AVClass ism_class = {
627    .class_name = "smooth streaming muxer",
628    .item_name  = av_default_item_name,
629    .option     = options,
630    .version    = LIBAVUTIL_VERSION_INT,
631};
632
633
634AVOutputFormat ff_smoothstreaming_muxer = {
635    .name           = "smoothstreaming",
636    .long_name      = NULL_IF_CONFIG_SMALL("Smooth Streaming Muxer"),
637    .priv_data_size = sizeof(SmoothStreamingContext),
638    .audio_codec    = AV_CODEC_ID_AAC,
639    .video_codec    = AV_CODEC_ID_H264,
640    .flags          = AVFMT_GLOBALHEADER | AVFMT_NOFILE,
641    .write_header   = ism_write_header,
642    .write_packet   = ism_write_packet,
643    .write_trailer  = ism_write_trailer,
644    .codec_tag      = (const AVCodecTag* const []){ ff_mp4_obj_type, 0 },
645    .priv_class     = &ism_class,
646};
647