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ffmpeg.wasm-core
Commit 13b350a3 authored by Aurelien Jacobs's avatar Aurelien Jacobs
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matroskadec: use generic parser to parse seekhead 

Originally committed as revision 14564 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 8ecdab8f
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Showing with 47 additions and 113 deletions
libavformat/matroskadec.c
View file @ 13b350a3
......@@ -163,6 +163,11 @@ typedef struct {
EbmlList pos;
} MatroskaIndex;
typedef struct {
uint64_t id;
uint64_t pos;
} MatroskaSeekhead;
typedef struct MatroskaLevel {
uint64_t start;
uint64_t length;
......@@ -184,6 +189,7 @@ typedef struct MatroskaDemuxContext {
EbmlList attachments;
EbmlList chapters;
EbmlList index;
EbmlList seekhead;
/* num_streams is the number of streams that av_new_stream() was called
* for ( = that are available to the calling program). */
......@@ -388,6 +394,19 @@ static EbmlSyntax matroska_tags[] = {
{ 0 }
};
static EbmlSyntax matroska_seekhead_entry[] = {
{ MATROSKA_ID_SEEKID, EBML_UINT, 0, offsetof(MatroskaSeekhead,id) },
{ MATROSKA_ID_SEEKPOSITION, EBML_UINT, 0, offsetof(MatroskaSeekhead,pos), {.u=-1} },
{ EBML_ID_VOID, EBML_NONE },
{ 0 }
};
static EbmlSyntax matroska_seekhead[] = {
{ MATROSKA_ID_SEEKENTRY, EBML_NEST, sizeof(MatroskaSeekhead), offsetof(MatroskaDemuxContext,seekhead), {.n=matroska_seekhead_entry} },
{ EBML_ID_VOID, EBML_NONE },
{ 0 }
};
/*
* The first few functions handle EBML file parsing. The rest
* is the document interpretation. Matroska really just is a
......@@ -1316,86 +1335,32 @@ matroska_parse_metadata (MatroskaDemuxContext *matroska)
static int
matroska_parse_seekhead (MatroskaDemuxContext *matroska)
{
int res = 0;
uint32_t id;
av_log(matroska->ctx, AV_LOG_DEBUG, "parsing seekhead...\n");
while (res == 0) {
if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
res = AVERROR(EIO);
break;
} else if (matroska->level_up) {
matroska->level_up--;
break;
}
switch (id) {
case MATROSKA_ID_SEEKENTRY: {
uint32_t seek_id = 0, peek_id_cache = 0;
uint64_t seek_pos = (uint64_t) -1, t;
int dummy_level = 0;
if ((res = ebml_read_master(matroska, &id)) < 0)
break;
while (res == 0) {
if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
res = AVERROR(EIO);
break;
} else if (matroska->level_up) {
matroska->level_up--;
break;
}
switch (id) {
case MATROSKA_ID_SEEKID:
res = ebml_read_uint(matroska, &id, &t);
seek_id = t;
break;
case MATROSKA_ID_SEEKPOSITION:
res = ebml_read_uint(matroska, &id, &seek_pos);
break;
default:
av_log(matroska->ctx, AV_LOG_INFO,
"Unknown seekhead ID 0x%x\n", id);
/* fall-through */
case EBML_ID_VOID:
res = ebml_read_skip(matroska);
break;
}
if (matroska->level_up) {
matroska->level_up--;
break;
}
}
if (!seek_id || seek_pos == (uint64_t) -1) {
av_log(matroska->ctx, AV_LOG_INFO,
"Incomplete seekhead entry (0x%x/%"PRIu64")\n",
seek_id, seek_pos);
break;
}
return ebml_parse(matroska, matroska_seekhead, matroska, MATROSKA_ID_SEEKHEAD, 0);
}
switch (seek_id) {
case MATROSKA_ID_CUES:
case MATROSKA_ID_TAGS: {
static void
matroska_execute_seekhead(MatroskaDemuxContext *matroska)
{
EbmlList *seekhead_list = &matroska->seekhead;
MatroskaSeekhead *seekhead = seekhead_list->elem;
uint32_t peek_id_cache = matroska->peek_id;
uint32_t level_up = matroska->level_up;
offset_t before_pos;
offset_t before_pos = url_ftell(matroska->ctx->pb);
int dummy_level = 0;
MatroskaLevel level;
uint32_t id;
int i, res;
/* remember the peeked ID and the current position */
peek_id_cache = matroska->peek_id;
before_pos = url_ftell(matroska->ctx->pb);
for (i=0; i<seekhead_list->nb_elem; i++) {
if (seekhead[i].pos <= before_pos
|| seekhead[i].id == MATROSKA_ID_SEEKHEAD
|| seekhead[i].id == MATROSKA_ID_CLUSTER)
continue;
/* seek */
if ((res = ebml_read_seek(matroska, seek_pos +
matroska->segment_start)) < 0)
goto finish;
if (ebml_read_seek(matroska,
seekhead[i].pos+matroska->segment_start) < 0)
continue;
/* we don't want to lose our seekhead level, so we add
* a dummy. This is a crude hack. */
......@@ -1403,7 +1368,7 @@ matroska_parse_seekhead (MatroskaDemuxContext *matroska)
av_log(matroska->ctx, AV_LOG_INFO,
"Max EBML element depth (%d) reached, "
"cannot parse further.\n", EBML_MAX_DEPTH);
return AVERROR_UNKNOWN;
break;
}
level.start = 0;
......@@ -1416,11 +1381,11 @@ matroska_parse_seekhead (MatroskaDemuxContext *matroska)
if (!(id = ebml_peek_id (matroska,
&matroska->level_up)))
goto finish;
if (id != seek_id) {
if (id != seekhead[i].id) {
av_log(matroska->ctx, AV_LOG_INFO,
"We looked for ID=0x%x but got "
"ID=0x%x (pos=%"PRIu64")",
seek_id, id, seek_pos +
(int)seekhead[i].id, id, seekhead[i].pos +
matroska->segment_start);
goto finish;
}
......@@ -1451,42 +1416,12 @@ matroska_parse_seekhead (MatroskaDemuxContext *matroska)
if (length == (uint64_t)-1)
break;
}
}
/* seek back */
if ((res = ebml_read_seek(matroska, before_pos)) < 0)
return res;
ebml_read_seek(matroska, before_pos);
matroska->peek_id = peek_id_cache;
matroska->level_up = level_up;
break;
}
default:
av_log(matroska->ctx, AV_LOG_INFO,
"Ignoring seekhead entry for ID=0x%x\n",
seek_id);
break;
}
break;
}
default:
av_log(matroska->ctx, AV_LOG_INFO,
"Unknown seekhead ID 0x%x\n", id);
/* fall-through */
case EBML_ID_VOID:
res = ebml_read_skip(matroska);
break;
}
if (matroska->level_up) {
matroska->level_up--;
break;
}
}
return res;
}
static int
......@@ -1667,8 +1602,6 @@ matroska_read_header (AVFormatContext *s,
/* file index (if seekable, seek to Cues/Tags to parse it) */
case MATROSKA_ID_SEEKHEAD: {
if ((res = ebml_read_master(matroska, &id)) < 0)
break;
res = matroska_parse_seekhead(matroska);
break;
}
......@@ -1705,6 +1638,7 @@ matroska_read_header (AVFormatContext *s,
break;
}
}
matroska_execute_seekhead(matroska);
/* Have we found a cluster? */
if (ebml_peek_id(matroska, NULL) == MATROSKA_ID_CLUSTER) {
......
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