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hlsenc: Support recovery from an already present playlist

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Parse the playlist to recover the start sequence and previously
generated segments and continue muxing from there.

Mainly useful for near-seamless recovery in live scenarios.
This commit is contained in:
Luca Barbato 2017-05-19 20:32:47 +02:00
parent 91622f6446
commit 16cb06bb30
1 changed files with 85 additions and 10 deletions
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95
libavformat/hlsenc.c
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@ -119,7 +119,7 @@ static int setup_encryption(AVFormatContext *s)
AVIOContext *out = NULL;
int len, ret;
uint8_t buf[16];
uint8_t *k;
uint8_t *k = NULL;
len = strlen(hls->basename) + 4 + 1;
hls->key_basename = av_mallocz(len);
@ -141,9 +141,22 @@ static int setup_encryption(AVFormatContext *s)
return ret;
k = hls->key;
} else {
if ((ret = randomize(buf, sizeof(buf))) < 0) {
av_log(s, AV_LOG_ERROR, "Cannot generate a strong random key\n");
return ret;
if (hls->start_sequence < 0) {
ret = s->io_open(s, &out, hls->key_basename, AVIO_FLAG_READ, NULL);
if (ret < 0) {
av_log(s, AV_LOG_WARNING,
"Cannot recover the key, generating a new one.\n");
} else {
avio_read(out, buf, 16);
k = buf;
avio_close(out);
}
}
if (!k) {
if ((ret = randomize(buf, sizeof(buf))) < 0) {
av_log(s, AV_LOG_ERROR, "Cannot generate a strong random key\n");
return ret;
}
}
if ((ret = dict_set_bin(&hls->enc_opts, "key", buf, sizeof(buf))) < 0)
@ -201,14 +214,14 @@ static int hls_mux_init(AVFormatContext *s)
return 0;
}
static int append_entry(HLSContext *hls, int64_t duration)
static int append_entry(HLSContext *hls, int64_t duration, const char *name)
{
ListEntry *en = av_malloc(sizeof(*en));
if (!en)
return AVERROR(ENOMEM);
av_strlcpy(en->name, av_basename(hls->avf->filename), sizeof(en->name));
av_strlcpy(en->name, name, sizeof(en->name));
en->duration = duration;
en->next = NULL;
@ -356,12 +369,67 @@ fail:
return err;
}
static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
{
int len = ff_get_line(s, buf, maxlen);
while (len > 0 && av_isspace(buf[len - 1]))
buf[--len] = '\0';
return len;
}
static int hls_recover(AVFormatContext *s)
{
HLSContext *hls = s->priv_data;
char line[1024];
AVIOContext *io;
const char *ptr;
int ret, is_segment = 0;
int64_t duration = 0;
ret = s->io_open(s, &io, s->filename, AVIO_FLAG_READ, NULL);
if (ret < 0) {
av_log(s, AV_LOG_WARNING,
"Cannot recover the playlist, generating a new one.\n");
hls->start_sequence = 0;
hls->sequence = 0;
return 0;
}
read_chomp_line(io, line, sizeof(line));
if (strcmp(line, "#EXTM3U")) {
av_log(s, AV_LOG_ERROR,
"The playlist file is present but unparsable."
" Please remove it.\n");
return AVERROR_INVALIDDATA;
}
while (!io->eof_reached) {
read_chomp_line(io, line, sizeof(line));
if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
hls->sequence = hls->start_sequence = atoi(ptr);
} else if (av_strstart(line, "#EXTINF:", &ptr)) {
is_segment = 1;
duration = atof(ptr) * AV_TIME_BASE;
} else if (av_strstart(line, "#", NULL)) {
continue;
} else if (line[0]) {
if (is_segment) {
append_entry(hls, duration, av_basename(line));
is_segment = 0;
}
}
}
return 0;
}
static int hls_setup(AVFormatContext *s)
{
HLSContext *hls = s->priv_data;
const char *pattern = "%d.ts";
int basename_size = strlen(s->filename) + strlen(pattern) + 1;
char *p;
int ret;
if (hls->encrypt)
basename_size += 7;
@ -382,7 +450,13 @@ static int hls_setup(AVFormatContext *s)
*p = '\0';
if (hls->encrypt) {
int ret = setup_encryption(s);
ret = setup_encryption(s);
if (ret < 0)
return ret;
}
if (hls->start_sequence < 0) {
ret = hls_recover(s);
if (ret < 0)
return ret;
}
@ -465,7 +539,7 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
hls->duration = pts - hls->end_pts;
if (can_split && pts - hls->start_pts >= end_pts) {
ret = append_entry(hls, hls->duration);
ret = append_entry(hls, hls->duration, av_basename(hls->avf->filename));
if (ret)
return ret;
@ -500,7 +574,7 @@ static int hls_write_trailer(struct AVFormatContext *s)
ff_format_io_close(s, &oc->pb);
avformat_free_context(oc);
av_free(hls->basename);
append_entry(hls, hls->duration);
append_entry(hls, hls->duration, av_basename(hls->avf->filename));
hls_window(s, 1);
free_entries(hls);
@ -511,7 +585,8 @@ static int hls_write_trailer(struct AVFormatContext *s)
#define OFFSET(x) offsetof(HLSContext, x)
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{"start_number", "first number in the sequence", OFFSET(start_sequence),AV_OPT_TYPE_INT64, {.i64 = 0}, 0, INT64_MAX, E},
{"start_number", "first number in the sequence", OFFSET(start_sequence),AV_OPT_TYPE_INT64, {.i64 = 0}, -1, INT64_MAX, E, "start_number"},
{"recover", "If there is already a m3u8 file in the path, populate the sequence from it", 0, AV_OPT_TYPE_CONST, {.i64 = -1}, 0, 0, E, "start_number"},
{"hls_time", "segment length in seconds", OFFSET(time), AV_OPT_TYPE_FLOAT, {.dbl = 2}, 0, FLT_MAX, E},
{"hls_list_size", "maximum number of playlist entries", OFFSET(size), AV_OPT_TYPE_INT, {.i64 = 5}, 0, INT_MAX, E},
{"hls_wrap", "number after which the index wraps", OFFSET(wrap), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E},