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

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Originally committed as revision 10358 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
David Conrad 2007-09-05 00:24:56 +00:00
parent cce800b456
commit baf71dca28
1 changed files with 76 additions and 43 deletions
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119
libavformat/matroskaenc.c
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@ -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);