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Paul Wilkins authored
Some minor refactoring code relating to estimates of bits per MB at a given Q and estimating the allowed Q range. Most of the changes here were included in a previous commit. This commit seeks to separate out the refactoring from more the material changes. Two #define control flags have been added for experimentation. ONE_SHOT_Q_ESTIMATE force the two pass encoder to use its initial Q range estimate for the whole clip even if this results in a miss on the target data rate. In effect this tightens the Q range seen at the expense of rate control accuracy. DISABLE_RC_LONG_TERM_MEM is a related flag that disables the long term memory in the rate control. Local adjustments are still made to try and better hit the rate target on a per frame basis but the impact of rate control misses is not propagated to the remainder of the clip. This means that for example an overshoot early on will not cause frames later in the clip to be starved of bits. Again the result of this relaxation amy be less rate control accuracy especially on short clips. The flags are disabled by default for now. Change-Id: I7482f980146d8ea033b5d50cc689f772e4bd119e
97da8b8c
/* * Copyright (c) 2013 The WebM project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */#include "webmenc.h"#include <limits.h>#include <string.h>#include "third_party/libmkv/EbmlWriter.h"#include "third_party/libmkv/EbmlIDs.h"void Ebml_Write(struct EbmlGlobal *glob, const void *buffer_in, unsigned long len) { (void) fwrite(buffer_in, 1, len, glob->stream);}#define WRITE_BUFFER(s) \for (i = len - 1; i >= 0; i--) { \ x = (char)(*(const s *)buffer_in >> (i * CHAR_BIT)); \ Ebml_Write(glob, &x, 1); \}void Ebml_Serialize(struct EbmlGlobal *glob, const void *buffer_in, int buffer_size, unsigned long len) { char x; int i; /* buffer_size: * 1 - int8_t; * 2 - int16_t; * 3 - int32_t; * 4 - int64_t; */ switch (buffer_size) { case 1: WRITE_BUFFER(int8_t) break; case 2: WRITE_BUFFER(int16_t) break; case 4: WRITE_BUFFER(int32_t) break; case 8: WRITE_BUFFER(int64_t) break; default: break; }}#undef WRITE_BUFFER/* Need a fixed size serializer for the track ID. libmkv provides a 64 bit * one, but not a 32 bit one. */static void Ebml_SerializeUnsigned32(struct EbmlGlobal *glob, unsigned int class_id, uint64_t ui) { const unsigned char sizeSerialized = 4 | 0x80; Ebml_WriteID(glob, class_id); Ebml_Serialize(glob, &sizeSerialized, sizeof(sizeSerialized), 1);7172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140
Ebml_Serialize(glob, &ui, sizeof(ui), 4);
}
static void Ebml_StartSubElement(struct EbmlGlobal *glob,
EbmlLoc *ebmlLoc,
unsigned int class_id) {
const uint64_t kEbmlUnknownLength = LITERALU64(0x01FFFFFF, 0xFFFFFFFF);
Ebml_WriteID(glob, class_id);
*ebmlLoc = ftello(glob->stream);
Ebml_Serialize(glob, &kEbmlUnknownLength, sizeof(kEbmlUnknownLength), 8);
}
static void Ebml_EndSubElement(struct EbmlGlobal *glob, EbmlLoc *ebmlLoc) {
off_t pos;
uint64_t size;
/* Save the current stream pointer. */
pos = ftello(glob->stream);
/* Calculate the size of this element. */
size = pos - *ebmlLoc - 8;
size |= LITERALU64(0x01000000, 0x00000000);
/* Seek back to the beginning of the element and write the new size. */
fseeko(glob->stream, *ebmlLoc, SEEK_SET);
Ebml_Serialize(glob, &size, sizeof(size), 8);
/* Reset the stream pointer. */
fseeko(glob->stream, pos, SEEK_SET);
}
void write_webm_seek_element(struct EbmlGlobal *ebml,
unsigned int id,
off_t pos) {
uint64_t offset = pos - ebml->position_reference;
EbmlLoc start;
Ebml_StartSubElement(ebml, &start, Seek);
Ebml_SerializeBinary(ebml, SeekID, id);
Ebml_SerializeUnsigned64(ebml, SeekPosition, offset);
Ebml_EndSubElement(ebml, &start);
}
void write_webm_seek_info(struct EbmlGlobal *ebml) {
off_t pos;
EbmlLoc start;
EbmlLoc startInfo;
uint64_t frame_time;
char version_string[64];
/* Save the current stream pointer. */
pos = ftello(ebml->stream);
if (ebml->seek_info_pos)
fseeko(ebml->stream, ebml->seek_info_pos, SEEK_SET);
else
ebml->seek_info_pos = pos;
Ebml_StartSubElement(ebml, &start, SeekHead);
write_webm_seek_element(ebml, Tracks, ebml->track_pos);
write_webm_seek_element(ebml, Cues, ebml->cue_pos);
write_webm_seek_element(ebml, Info, ebml->segment_info_pos);
Ebml_EndSubElement(ebml, &start);
/* Create and write the Segment Info. */
if (ebml->debug) {
strcpy(version_string, "vpxenc");
} else {
strcpy(version_string, "vpxenc ");
strncat(version_string,
vpx_codec_version_str(),
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sizeof(version_string) - 1 - strlen(version_string));
}
frame_time = (uint64_t)1000 * ebml->framerate.den
/ ebml->framerate.num;
ebml->segment_info_pos = ftello(ebml->stream);
Ebml_StartSubElement(ebml, &startInfo, Info);
Ebml_SerializeUnsigned(ebml, TimecodeScale, 1000000);
Ebml_SerializeFloat(ebml, Segment_Duration,
(double)(ebml->last_pts_ms + frame_time));
Ebml_SerializeString(ebml, 0x4D80, version_string);
Ebml_SerializeString(ebml, 0x5741, version_string);
Ebml_EndSubElement(ebml, &startInfo);
}
void write_webm_file_header(struct EbmlGlobal *glob,
const vpx_codec_enc_cfg_t *cfg,
const struct vpx_rational *fps,
stereo_format_t stereo_fmt,
unsigned int fourcc) {
EbmlLoc start;
EbmlLoc trackStart;
EbmlLoc videoStart;
unsigned int trackNumber = 1;
uint64_t trackID = 0;
unsigned int pixelWidth = cfg->g_w;
unsigned int pixelHeight = cfg->g_h;
/* Write the EBML header. */
Ebml_StartSubElement(glob, &start, EBML);
Ebml_SerializeUnsigned(glob, EBMLVersion, 1);
Ebml_SerializeUnsigned(glob, EBMLReadVersion, 1);
Ebml_SerializeUnsigned(glob, EBMLMaxIDLength, 4);
Ebml_SerializeUnsigned(glob, EBMLMaxSizeLength, 8);
Ebml_SerializeString(glob, DocType, "webm");
Ebml_SerializeUnsigned(glob, DocTypeVersion, 2);
Ebml_SerializeUnsigned(glob, DocTypeReadVersion, 2);
Ebml_EndSubElement(glob, &start);
/* Open and begin writing the segment element. */
Ebml_StartSubElement(glob, &glob->startSegment, Segment);
glob->position_reference = ftello(glob->stream);
glob->framerate = *fps;
write_webm_seek_info(glob);
/* Open and write the Tracks element. */
glob->track_pos = ftello(glob->stream);
Ebml_StartSubElement(glob, &trackStart, Tracks);
/* Open and write the Track entry. */
Ebml_StartSubElement(glob, &start, TrackEntry);
Ebml_SerializeUnsigned(glob, TrackNumber, trackNumber);
glob->track_id_pos = ftello(glob->stream);
Ebml_SerializeUnsigned32(glob, TrackUID, trackID);
Ebml_SerializeUnsigned(glob, TrackType, 1);
Ebml_SerializeString(glob, CodecID,
fourcc == VP8_FOURCC ? "V_VP8" : "V_VP9");
Ebml_StartSubElement(glob, &videoStart, Video);
Ebml_SerializeUnsigned(glob, PixelWidth, pixelWidth);
Ebml_SerializeUnsigned(glob, PixelHeight, pixelHeight);
Ebml_SerializeUnsigned(glob, StereoMode, stereo_fmt);
Ebml_EndSubElement(glob, &videoStart);
/* Close Track entry. */
Ebml_EndSubElement(glob, &start);
/* Close Tracks element. */
Ebml_EndSubElement(glob, &trackStart);
/* Segment element remains open. */
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}
void write_webm_block(struct EbmlGlobal *glob,
const vpx_codec_enc_cfg_t *cfg,
const vpx_codec_cx_pkt_t *pkt) {
unsigned int block_length;
unsigned char track_number;
uint16_t block_timecode = 0;
unsigned char flags;
int64_t pts_ms;
int start_cluster = 0, is_keyframe;
/* Calculate the PTS of this frame in milliseconds. */
pts_ms = pkt->data.frame.pts * 1000
* (uint64_t)cfg->g_timebase.num / (uint64_t)cfg->g_timebase.den;
if (pts_ms <= glob->last_pts_ms)
pts_ms = glob->last_pts_ms + 1;
glob->last_pts_ms = pts_ms;
/* Calculate the relative time of this block. */
if (pts_ms - glob->cluster_timecode > SHRT_MAX)
start_cluster = 1;
else
block_timecode = (uint16_t)pts_ms - glob->cluster_timecode;
is_keyframe = (pkt->data.frame.flags & VPX_FRAME_IS_KEY);
if (start_cluster || is_keyframe) {
if (glob->cluster_open)
Ebml_EndSubElement(glob, &glob->startCluster);
/* Open the new cluster. */
block_timecode = 0;
glob->cluster_open = 1;
glob->cluster_timecode = (uint32_t)pts_ms;
glob->cluster_pos = ftello(glob->stream);
Ebml_StartSubElement(glob, &glob->startCluster, Cluster);
Ebml_SerializeUnsigned(glob, Timecode, glob->cluster_timecode);
/* Save a cue point if this is a keyframe. */
if (is_keyframe) {
struct cue_entry *cue, *new_cue_list;
new_cue_list = realloc(glob->cue_list,
(glob->cues + 1) * sizeof(struct cue_entry));
if (new_cue_list)
glob->cue_list = new_cue_list;
else
fatal("Failed to realloc cue list.");
cue = &glob->cue_list[glob->cues];
cue->time = glob->cluster_timecode;
cue->loc = glob->cluster_pos;
glob->cues++;
}
}
/* Write the Simple Block. */
Ebml_WriteID(glob, SimpleBlock);
block_length = (unsigned int)pkt->data.frame.sz + 4;
block_length |= 0x10000000;
Ebml_Serialize(glob, &block_length, sizeof(block_length), 4);
track_number = 1;
track_number |= 0x80;
Ebml_Write(glob, &track_number, 1);
Ebml_Serialize(glob, &block_timecode, sizeof(block_timecode), 2);
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flags = 0;
if (is_keyframe)
flags |= 0x80;
if (pkt->data.frame.flags & VPX_FRAME_IS_INVISIBLE)
flags |= 0x08;
Ebml_Write(glob, &flags, 1);
Ebml_Write(glob, pkt->data.frame.buf, (unsigned int)pkt->data.frame.sz);
}
void write_webm_file_footer(struct EbmlGlobal *glob, int hash) {
EbmlLoc start_cues;
EbmlLoc start_cue_point;
EbmlLoc start_cue_tracks;
unsigned int i;
if (glob->cluster_open)
Ebml_EndSubElement(glob, &glob->startCluster);
glob->cue_pos = ftello(glob->stream);
Ebml_StartSubElement(glob, &start_cues, Cues);
for (i = 0; i < glob->cues; i++) {
struct cue_entry *cue = &glob->cue_list[i];
Ebml_StartSubElement(glob, &start_cue_point, CuePoint);
Ebml_SerializeUnsigned(glob, CueTime, cue->time);
Ebml_StartSubElement(glob, &start_cue_tracks, CueTrackPositions);
Ebml_SerializeUnsigned(glob, CueTrack, 1);
Ebml_SerializeUnsigned64(glob, CueClusterPosition,
cue->loc - glob->position_reference);
Ebml_EndSubElement(glob, &start_cue_tracks);
Ebml_EndSubElement(glob, &start_cue_point);
}
Ebml_EndSubElement(glob, &start_cues);
/* Close the Segment. */
Ebml_EndSubElement(glob, &glob->startSegment);
/* Patch up the seek info block. */
write_webm_seek_info(glob);
/* Patch up the track id. */
fseeko(glob->stream, glob->track_id_pos, SEEK_SET);
Ebml_SerializeUnsigned32(glob, TrackUID, glob->debug ? 0xDEADBEEF : hash);
fseeko(glob->stream, 0, SEEK_END);
}