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ffmpeg.wasm-core
Commit baf71dca authored by David Conrad's avatar David Conrad
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Calculate the size of key EBML master elements beforehand so only just enough... 

Calculate the size of key EBML master elements beforehand so only just enough size is reserved for the size

Originally committed as revision 10358 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent cce800b4
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Showing with 76 additions and 43 deletions
libavformat/matroskaenc.c
View file @ baf71dca
......@@ -25,6 +25,11 @@
#include "xiph.h"
#include "matroska.h"
typedef struct ebml_master {
offset_t pos; ///< absolute offset in the file where the master's elements start
int sizebytes; ///< how many bytes were reserved for the size
} ebml_master;
typedef struct mkv_seekhead_entry {
unsigned int elementid;
uint64_t segmentpos;
......@@ -52,10 +57,10 @@ typedef struct {
} mkv_cues;
typedef struct MatroskaMuxContext {
offset_t segment;
ebml_master segment;
offset_t segment_offset;
offset_t segment_uid;
offset_t cluster;
ebml_master cluster;
offset_t cluster_pos; ///< file offset of the current cluster
uint64_t cluster_pts;
offset_t duration_offset;
......@@ -67,6 +72,17 @@ typedef struct MatroskaMuxContext {
struct AVMD5 *md5_ctx;
} MatroskaMuxContext;
// 2 bytes * 3 for EBML IDs, 3 1-byte EBML lengths, 8 bytes for 64 bit offset, 4 bytes for target EBML ID
#define MAX_SEEKENTRY_SIZE 21
// per-cuepoint-track - 3 1-byte EBML IDs, 3 1-byte EBML sizes, 2 8-byte uint max
#define MAX_CUETRACKPOS_SIZE 22
// per-cuepoint - 2 1-byte EBML IDs, 2 1-byte EBML sizes, 8-byte uint max
#define MAX_CUEPOINT_SIZE(num_tracks) 12 + MAX_CUETRACKPOS_SIZE*num_tracks
static int ebml_id_size(unsigned int id)
{
return (av_log2(id+1)-1)/7+1;
......@@ -194,21 +210,20 @@ static void put_ebml_void(ByteIOContext *pb, uint64_t size)
url_fseek(pb, currentpos + size, SEEK_SET);
}
static offset_t start_ebml_master(ByteIOContext *pb, unsigned int elementid)
static ebml_master start_ebml_master(ByteIOContext *pb, unsigned int elementid, uint64_t expectedsize)
{
int bytes = expectedsize ? ebml_size_bytes(expectedsize) : 8;
put_ebml_id(pb, elementid);
// XXX: this always reserves the maximum needed space to store any size value
// we should be smarter (additional parameter for expected size?)
put_ebml_size_unknown(pb, 8);
return url_ftell(pb);
put_ebml_size_unknown(pb, bytes);
return (ebml_master){ url_ftell(pb), bytes };
}
static void end_ebml_master(ByteIOContext *pb, offset_t start)
static void end_ebml_master(ByteIOContext *pb, ebml_master master)
{
offset_t pos = url_ftell(pb);
url_fseek(pb, start - 8, SEEK_SET);
put_ebml_size(pb, pos - start, 8);
url_fseek(pb, master.pos - master.sizebytes, SEEK_SET);
put_ebml_size(pb, pos - master.pos, master.sizebytes);
url_fseek(pb, pos, SEEK_SET);
}
......@@ -241,8 +256,7 @@ static mkv_seekhead * mkv_start_seekhead(ByteIOContext *pb, offset_t segment_off
new_seekhead->filepos = url_ftell(pb);
// 21 bytes max for a seek entry, 10 bytes max for the SeekHead ID and size,
// and 3 bytes to guarantee that an EBML void element will fit afterwards
// XXX: 28 bytes right now because begin_ebml_master() reserves more than necessary
new_seekhead->reserved_size = numelements * 28 + 13;
new_seekhead->reserved_size = numelements * MAX_SEEKENTRY_SIZE + 13;
new_seekhead->max_entries = numelements;
put_ebml_void(pb, new_seekhead->reserved_size);
}
......@@ -280,7 +294,8 @@ static int mkv_add_seekhead_entry(mkv_seekhead *seekhead, unsigned int elementid
*/
static offset_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
{
offset_t metaseek, seekentry, currentpos;
ebml_master metaseek, seekentry;
offset_t currentpos;
int i;
currentpos = url_ftell(pb);
......@@ -288,11 +303,11 @@ static offset_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
if (seekhead->reserved_size > 0)
url_fseek(pb, seekhead->filepos, SEEK_SET);
metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD);
metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD, seekhead->reserved_size);
for (i = 0; i < seekhead->num_entries; i++) {
mkv_seekhead_entry *entry = &seekhead->entries[i];
seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY);
seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY, MAX_SEEKENTRY_SIZE);
put_ebml_id(pb, MATROSKA_ID_SEEKID);
put_ebml_size(pb, ebml_id_size(entry->elementid), 0);
......@@ -344,26 +359,27 @@ static int mkv_add_cuepoint(mkv_cues *cues, AVPacket *pkt, offset_t cluster_pos)
return 0;
}
static offset_t mkv_write_cues(ByteIOContext *pb, mkv_cues *cues)
static offset_t mkv_write_cues(ByteIOContext *pb, mkv_cues *cues, int num_tracks)
{
offset_t currentpos, cues_element;
ebml_master cues_element;
offset_t currentpos;
int i, j;
currentpos = url_ftell(pb);
cues_element = start_ebml_master(pb, MATROSKA_ID_CUES);
cues_element = start_ebml_master(pb, MATROSKA_ID_CUES, 0);
for (i = 0; i < cues->num_entries; i++) {
offset_t cuepoint, track_positions;
ebml_master cuepoint, track_positions;
mkv_cuepoint *entry = &cues->entries[i];
uint64_t pts = entry->pts;
cuepoint = start_ebml_master(pb, MATROSKA_ID_POINTENTRY);
cuepoint = start_ebml_master(pb, MATROSKA_ID_POINTENTRY, MAX_CUEPOINT_SIZE(num_tracks));
put_ebml_uint(pb, MATROSKA_ID_CUETIME, pts);
// put all the entries from different tracks that have the exact same
// timestamp into the same CuePoint
for (j = 0; j < cues->num_entries - i && entry[j].pts == pts; j++) {
track_positions = start_ebml_master(pb, MATROSKA_ID_CUETRACKPOSITION);
track_positions = start_ebml_master(pb, MATROSKA_ID_CUETRACKPOSITION, MAX_CUETRACKPOS_SIZE);
put_ebml_uint(pb, MATROSKA_ID_CUETRACK , entry[j].tracknum );
put_ebml_uint(pb, MATROSKA_ID_CUECLUSTERPOSITION, entry[j].cluster_pos);
end_ebml_master(pb, track_positions);
......@@ -380,7 +396,7 @@ static offset_t mkv_write_cues(ByteIOContext *pb, mkv_cues *cues)
static int put_xiph_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
{
offset_t codecprivate;
ebml_master codecprivate;
uint8_t *header_start[3];
int header_len[3];
int first_header_size;
......@@ -397,7 +413,7 @@ static int put_xiph_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
return -1;
}
codecprivate = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
codecprivate = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
put_byte(pb, 2); // number packets - 1
for (j = 0; j < 2; j++) {
put_xiph_size(pb, header_len[j]);
......@@ -413,7 +429,7 @@ static int put_xiph_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
static int put_flac_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
{
offset_t codecpriv = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
ebml_master codecpriv = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
// if the extradata_size is greater than FLAC_STREAMINFO_SIZE,
// assume that it's in Matroska's format already
......@@ -466,17 +482,17 @@ static int mkv_write_tracks(AVFormatContext *s)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = &s->pb;
offset_t tracks;
ebml_master tracks;
int i, j;
if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, url_ftell(pb)) < 0)
return -1;
tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS);
tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS, 0);
for (i = 0; i < s->nb_streams; i++) {
AVStream *st = s->streams[i];
AVCodecContext *codec = st->codec;
offset_t subinfo, track;
ebml_master subinfo, track;
int native_id = 0;
int bit_depth = av_get_bits_per_sample(codec->codec_id);
int sample_rate = codec->sample_rate;
......@@ -485,7 +501,7 @@ static int mkv_write_tracks(AVFormatContext *s)
if (codec->codec_id == CODEC_ID_AAC)
get_aac_sample_rates(codec, &sample_rate, &output_sample_rate);
track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY);
track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY, 0);
put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER , i + 1);
put_ebml_uint (pb, MATROSKA_ID_TRACKUID , i + 1);
put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0); // no lacing (yet)
......@@ -521,17 +537,17 @@ static int mkv_write_tracks(AVFormatContext *s)
put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
if (!native_id) {
offset_t bmp_header;
ebml_master bmp_header;
// if there is no mkv-specific codec id, use VFW mode
if (!codec->codec_tag)
codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
put_bmp_header(pb, codec, codec_bmp_tags, 0);
end_ebml_master(pb, bmp_header);
}
subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO);
subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO, 0);
// XXX: interlace flag?
put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
......@@ -546,7 +562,7 @@ static int mkv_write_tracks(AVFormatContext *s)
put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
if (!native_id) {
offset_t wav_header;
ebml_master wav_header;
// no mkv-specific ID, use ACM mode
codec->codec_tag = codec_get_tag(codec_wav_tags, codec->codec_id);
if (!codec->codec_tag) {
......@@ -555,11 +571,11 @@ static int mkv_write_tracks(AVFormatContext *s)
}
put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_AUDIO_ACM);
wav_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
wav_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE, 0);
put_wav_header(pb, codec);
end_ebml_master(pb, wav_header);
}
subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO);
subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO, 0);
put_ebml_uint (pb, MATROSKA_ID_AUDIOCHANNELS , codec->channels);
put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
if (output_sample_rate)
......@@ -589,12 +605,12 @@ static int mkv_write_header(AVFormatContext *s)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = &s->pb;
offset_t ebml_header, segment_info;
ebml_master ebml_header, segment_info;
mkv->md5_ctx = av_mallocz(av_md5_size);
av_md5_init(mkv->md5_ctx);
ebml_header = start_ebml_master(pb, EBML_ID_HEADER);
ebml_header = start_ebml_master(pb, EBML_ID_HEADER, 0);
put_ebml_uint (pb, EBML_ID_EBMLVERSION , 1);
put_ebml_uint (pb, EBML_ID_EBMLREADVERSION , 1);
put_ebml_uint (pb, EBML_ID_EBMLMAXIDLENGTH , 4);
......@@ -604,7 +620,7 @@ static int mkv_write_header(AVFormatContext *s)
put_ebml_uint (pb, EBML_ID_DOCTYPEREADVERSION , 2);
end_ebml_master(pb, ebml_header);
mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT);
mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT, 0);
mkv->segment_offset = url_ftell(pb);
// we write 2 seek heads - one at the end of the file to point to each cluster, and
......@@ -617,7 +633,7 @@ static int mkv_write_header(AVFormatContext *s)
if (mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_INFO, url_ftell(pb)) < 0)
return -1;
segment_info = start_ebml_master(pb, MATROSKA_ID_INFO);
segment_info = start_ebml_master(pb, MATROSKA_ID_INFO, 0);
put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
if (strlen(s->title))
put_ebml_string(pb, MATROSKA_ID_TITLE, s->title);
......@@ -643,7 +659,7 @@ static int mkv_write_header(AVFormatContext *s)
return -1;
mkv->cluster_pos = url_ftell(pb);
mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER);
mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, 0);
mkv->cluster_pts = 0;
......@@ -654,6 +670,23 @@ static int mkv_write_header(AVFormatContext *s)
return 0;
}
static int mkv_block_size(AVPacket *pkt)
{
int size = 4; // track num + timecode + flags
return size + pkt->size;
}
static int mkv_blockgroup_size(AVPacket *pkt)
{
int size = mkv_block_size(pkt);
size += ebml_size_bytes(size);
size += 2; // EBML ID for block and block duration
size += 8; // max size of block duration
size += ebml_size_bytes(size);
size += 1; // blockgroup EBML ID
return size;
}
static void mkv_write_block(AVFormatContext *s, unsigned int blockid, AVPacket *pkt, int flags)
{
MatroskaMuxContext *mkv = s->priv_data;
......@@ -662,7 +695,7 @@ static void mkv_write_block(AVFormatContext *s, unsigned int blockid, AVPacket *
av_log(s, AV_LOG_DEBUG, "Writing block at offset %llu, size %d, pts %lld, dts %lld, duration %d, flags %d\n",
url_ftell(pb), pkt->size, pkt->pts, pkt->dts, pkt->duration, flags);
put_ebml_id(pb, blockid);
put_ebml_size(pb, pkt->size + 4, 0);
put_ebml_size(pb, mkv_block_size(pkt), 0);
put_byte(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126
put_be16(pb, pkt->pts - mkv->cluster_pts);
put_byte(pb, flags);
......@@ -685,7 +718,7 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
return -1;
mkv->cluster_pos = url_ftell(pb);
mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER);
mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
mkv->cluster_pts = pkt->pts;
av_md5_update(mkv->md5_ctx, pkt->data, FFMIN(200, pkt->size));
......@@ -694,7 +727,7 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
if (codec->codec_type != CODEC_TYPE_SUBTITLE) {
mkv_write_block(s, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe << 7);
} else {
offset_t blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP);
ebml_master blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(pkt));
mkv_write_block(s, MATROSKA_ID_BLOCK, pkt, 0);
put_ebml_uint(pb, MATROSKA_ID_DURATION, pkt->duration);
end_ebml_master(pb, blockgroup);
......@@ -717,7 +750,7 @@ static int mkv_write_trailer(AVFormatContext *s)
end_ebml_master(pb, mkv->cluster);
cuespos = mkv_write_cues(pb, mkv->cues);
cuespos = mkv_write_cues(pb, mkv->cues, s->nb_streams);
second_seekhead = mkv_write_seekhead(pb, mkv->cluster_seekhead);
mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CUES , cuespos);
......
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