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ffmpeg.wasm-core
Commit 155e9ee9 authored by Fabrice Bellard's avatar Fabrice Bellard
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initial seek support 

Originally committed as revision 2502 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 27f388aa
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Showing with 294 additions and 26 deletions
libavformat/avi.h
View file @ 155e9ee9
......@@ -13,6 +13,9 @@
#define AVI_MAX_RIFF_SIZE 0x40000000LL
#define AVI_MASTER_INDEX_SIZE 256
/* index flags */
#define AVIIF_INDEX 0x10
offset_t start_tag(ByteIOContext *pb, const char *tag);
void end_tag(ByteIOContext *pb, offset_t start);
......
libavformat/avidec.c
View file @ 155e9ee9
......@@ -21,18 +21,33 @@
#include "dv.h"
//#define DEBUG
typedef struct AVIIndex {
unsigned char tag[4];
unsigned int flags, pos, len;
struct AVIIndex *next;
} AVIIndex;
//#define DEBUG_SEEK
typedef struct AVIIndexEntry {
unsigned int flags;
unsigned int pos;
unsigned int cum_len; /* sum of all lengths before this packet */
} AVIIndexEntry;
typedef struct AVIStream {
AVIIndexEntry *index_entries;
int nb_index_entries;
int index_entries_allocated_size;
int frame_offset; /* current frame (video) or byte (audio) counter
(used to compute the pts) */
int scale;
int rate;
int sample_size; /* audio only data */
int new_frame_offset; /* temporary storage (used during seek) */
int cum_len; /* temporary storage (used during seek) */
} AVIStream;
typedef struct {
int64_t riff_end;
int64_t movi_end;
offset_t movi_list;
AVIIndex *first, *last;
int index_loaded;
DVDemuxContext* dv_demux;
} AVIContext;
......@@ -74,8 +89,11 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
unsigned int size, nb_frames;
int i, n;
AVStream *st;
AVIStream *ast;
int xan_video = 0; /* hack to support Xan A/V */
av_set_pts_info(s, 64, 1, AV_TIME_BASE);
if (get_riff(avi, pb) < 0)
return -1;
......@@ -100,7 +118,8 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
print_tag("list", tag1, 0);
#endif
if (tag1 == MKTAG('m', 'o', 'v', 'i')) {
avi->movi_end = url_ftell(pb) + size - 4;
avi->movi_list = url_ftell(pb) - 4;
avi->movi_end = avi->movi_list + size;
#ifdef DEBUG
printf("movi end=%Lx\n", avi->movi_end);
#endif
......@@ -115,9 +134,14 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
url_fskip(pb, 4 * 4);
n = get_le32(pb);
for(i=0;i<n;i++) {
AVIStream *ast;
st = av_new_stream(s, i);
if (!st)
goto fail;
ast = av_mallocz(sizeof(AVIStream));
if (!ast)
goto fail;
st->priv_data = ast;
}
url_fskip(pb, size - 7 * 4);
break;
......@@ -159,7 +183,8 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
}
st = s->streams[stream_index];
ast = st->priv_data;
get_le32(pb); /* flags */
get_le16(pb); /* priority */
get_le16(pb); /* language */
......@@ -168,27 +193,28 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
rate = get_le32(pb); /* rate */
if(scale && rate){
st->codec.frame_rate = rate;
st->codec.frame_rate_base = scale;
}else if(frame_period){
st->codec.frame_rate = 1000000;
st->codec.frame_rate_base = frame_period;
rate = 1000000;
scale = frame_period;
}else{
st->codec.frame_rate = 25;
st->codec.frame_rate_base = 1;
rate = 25;
scale = 1;
}
ast->rate = rate;
ast->scale = scale;
st->codec.frame_rate = rate;
st->codec.frame_rate_base = scale;
get_le32(pb); /* start */
nb_frames = get_le32(pb);
st->start_time = 0;
st->duration = (double)nb_frames *
st->codec.frame_rate_base * AV_TIME_BASE /
st->codec.frame_rate;
url_fskip(pb, size - 9 * 4);
break;
case MKTAG('a', 'u', 'd', 's'):
{
unsigned int length, rate;
unsigned int length;
codec_type = CODEC_TYPE_AUDIO;
......@@ -197,19 +223,23 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
break;
}
st = s->streams[stream_index];
ast = st->priv_data;
get_le32(pb); /* flags */
get_le16(pb); /* priority */
get_le16(pb); /* language */
get_le32(pb); /* initial frame */
get_le32(pb); /* scale */
rate = get_le32(pb);
ast->scale = get_le32(pb); /* scale */
ast->rate = get_le32(pb);
get_le32(pb); /* start */
length = get_le32(pb); /* length, in samples or bytes */
get_le32(pb); /* buffer size */
get_le32(pb); /* quality */
ast->sample_size = get_le32(pb); /* sample ssize */
st->start_time = 0;
if (rate != 0)
st->duration = (int64_t)length * AV_TIME_BASE / rate;
url_fskip(pb, size - 9 * 4);
if (ast->rate != 0)
st->duration = (int64_t)length * AV_TIME_BASE / ast->rate;
url_fskip(pb, size - 12 * 4);
}
break;
default:
......@@ -274,6 +304,9 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
url_fskip(pb, 1);
/* special case time: To support Xan DPCM, hardcode
* the format if Xxan is the video codec */
st->need_parsing = 1;
/* force parsing as several audio frames can be in
one packet */
if (xan_video)
st->codec.codec_id = CODEC_ID_XAN_DPCM;
break;
......@@ -377,10 +410,31 @@ static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
size = dv_produce_packet(avi->dv_demux, pkt,
pkt->data, pkt->size);
pkt->destruct = dstr;
pkt->flags |= PKT_FLAG_KEY;
} else {
AVStream *st;
AVIStream *ast;
st = s->streams[n];
ast = st->priv_data;
/* XXX: how to handle B frames in avi ? */
pkt->pts = ((int64_t)ast->frame_offset * ast->scale* AV_TIME_BASE) / ast->rate;
pkt->stream_index = n;
pkt->flags |= PKT_FLAG_KEY; // FIXME: We really should read
// index for that
/* FIXME: We really should read index for that */
if (st->codec.codec_type == CODEC_TYPE_VIDEO) {
if (ast->frame_offset < ast->nb_index_entries) {
if (ast->index_entries[ast->frame_offset].flags & AVIIF_INDEX)
pkt->flags |= PKT_FLAG_KEY;
} else {
/* if no index, better to say that all frames
are key frames */
pkt->flags |= PKT_FLAG_KEY;
}
ast->frame_offset++;
} else {
ast->frame_offset += pkt->size;
pkt->flags |= PKT_FLAG_KEY;
}
}
return size;
}
......@@ -388,6 +442,214 @@ static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
return -1;
}
/* XXX: we make the implicit supposition that the position are sorted
for each stream */
static int avi_read_idx1(AVFormatContext *s, int size)
{
ByteIOContext *pb = &s->pb;
int nb_index_entries, i;
AVStream *st;
AVIStream *ast;
AVIIndexEntry *ie, *entries;
unsigned int index, tag, flags, pos, len;
nb_index_entries = size / 16;
if (nb_index_entries <= 0)
return -1;
/* read the entries and sort them in each stream component */
for(i = 0; i < nb_index_entries; i++) {
tag = get_le32(pb);
flags = get_le32(pb);
pos = get_le32(pb);
len = get_le32(pb);
#if defined(DEBUG_SEEK) && 0
printf("%d: tag=0x%x flags=0x%x pos=0x%x len=%d\n",
i, tag, flags, pos, len);
#endif
index = ((tag & 0xff) - '0') * 10;
index += ((tag >> 8) & 0xff) - '0';
if (index >= s->nb_streams)
continue;
st = s->streams[index];
ast = st->priv_data;
entries = av_fast_realloc(ast->index_entries,
&ast->index_entries_allocated_size,
(ast->nb_index_entries + 1) *
sizeof(AVIIndexEntry));
if (entries) {
ast->index_entries = entries;
ie = &entries[ast->nb_index_entries++];
ie->flags = flags;
ie->pos = pos;
ie->cum_len = ast->cum_len;
ast->cum_len += len;
}
}
return 0;
}
static int avi_load_index(AVFormatContext *s)
{
AVIContext *avi = s->priv_data;
ByteIOContext *pb = &s->pb;
uint32_t tag, size;
url_fseek(pb, avi->movi_end, SEEK_SET);
#ifdef DEBUG_SEEK
printf("movi_end=0x%llx\n", avi->movi_end);
#endif
for(;;) {
if (url_feof(pb))
break;
tag = get_le32(pb);
size = get_le32(pb);
#ifdef DEBUG_SEEK
printf("tag=%c%c%c%c size=0x%x\n",
tag & 0xff,
(tag >> 8) & 0xff,
(tag >> 16) & 0xff,
(tag >> 24) & 0xff,
size);
#endif
switch(tag) {
case MKTAG('i', 'd', 'x', '1'):
if (avi_read_idx1(s, size) < 0)
goto skip;
else
goto the_end;
break;
default:
skip:
size += (size & 1);
url_fskip(pb, size);
break;
}
}
the_end:
return 0;
}
/* return the index entry whose position is immediately >= 'wanted_pos' */
static int locate_frame_in_index(AVIIndexEntry *entries,
int nb_entries, int wanted_pos)
{
int a, b, m, pos;
a = 0;
b = nb_entries - 1;
while (a <= b) {
m = (a + b) >> 1;
pos = entries[m].pos;
if (pos == wanted_pos)
goto found;
else if (pos > wanted_pos) {
b = m - 1;
} else {
a = m + 1;
}
}
m = a;
if (m > 0)
m--;
found:
return m;
}
static int avi_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp)
{
AVIContext *avi = s->priv_data;
AVStream *st;
AVIStream *ast;
int frame_number, i;
int64_t pos;
if (!avi->index_loaded) {
/* we only load the index on demand */
avi_load_index(s);
avi->index_loaded = 1;
}
if (stream_index < 0) {
for(i = 0; i < s->nb_streams; i++) {
st = s->streams[i];
if (st->codec.codec_type == CODEC_TYPE_VIDEO)
goto found;
}
return -1;
found:
stream_index = i;
}
st = s->streams[stream_index];
if (st->codec.codec_type != CODEC_TYPE_VIDEO)
return -1;
ast = st->priv_data;
/* compute the frame number */
frame_number = (timestamp * ast->rate) /
(ast->scale * (int64_t)AV_TIME_BASE);
#ifdef DEBUG_SEEK
printf("timestamp=%0.3f nb_indexes=%d frame_number=%d\n",
(double)timestamp / AV_TIME_BASE,
ast->nb_index_entries, frame_number);
#endif
/* find a closest key frame before */
if (frame_number >= ast->nb_index_entries)
return -1;
while (frame_number >= 0 &&
!(ast->index_entries[frame_number].flags & AVIIF_INDEX))
frame_number--;
if (frame_number < 0)
return -1;
ast->new_frame_offset = frame_number;
/* find the position */
pos = ast->index_entries[frame_number].pos;
#ifdef DEBUG_SEEK
printf("key_frame_number=%d pos=0x%llx\n",
frame_number, pos);
#endif
/* update the frame counters for all the other stream by looking
at the positions just after the one found */
for(i = 0; i < s->nb_streams; i++) {
int j;
if (i != stream_index) {
st = s->streams[i];
ast = st->priv_data;
if (ast->nb_index_entries <= 0)
return -1;
j = locate_frame_in_index(ast->index_entries,
ast->nb_index_entries,
pos);
/* get next frame */
if ((j + 1) < ast->nb_index_entries)
j++;
/* extract the current frame number */
if (st->codec.codec_type == CODEC_TYPE_VIDEO)
ast->new_frame_offset = j;
else
ast->new_frame_offset = ast->index_entries[j].cum_len;
}
}
/* everything is OK now. We can update the frame offsets */
for(i = 0; i < s->nb_streams; i++) {
st = s->streams[i];
ast = st->priv_data;
ast->frame_offset = ast->new_frame_offset;
#ifdef DEBUG_SEEK
printf("%d: frame_offset=%d\n", i,
ast->frame_offset);
#endif
}
/* do the seek */
pos += avi->movi_list;
url_fseek(&s->pb, pos, SEEK_SET);
return 0;
}
static int avi_read_close(AVFormatContext *s)
{
int i;
......@@ -395,7 +657,9 @@ static int avi_read_close(AVFormatContext *s)
for(i=0;i<s->nb_streams;i++) {
AVStream *st = s->streams[i];
// av_free(st->priv_data);
AVIStream *ast = st->priv_data;
av_free(ast->index_entries);
av_free(ast);
av_free(st->codec.extradata);
av_free(st->codec.palctrl);
}
......@@ -428,6 +692,7 @@ static AVInputFormat avi_iformat = {
avi_read_header,
avi_read_packet,
avi_read_close,
avi_read_seek,
};
int avidec_init(void)
......
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