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mpv/demux/packet.c

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/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <libavcodec/avcodec.h>
#include <libavutil/hdr_dynamic_metadata.h>
#include <libavutil/intreadwrite.h>
#include "common/av_common.h"
#include "common/common.h"
#include "demux.h"
#include "demux/ebml.h"
#include "packet.h"
// Free any refcounted data dp holds (but don't free dp itself). This does not
// care about pointers that are _not_ refcounted (like demux_packet.codec).
// Normally, a user should use talloc_free(dp). This function is only for
// annoyingly specific obscure use cases.
void demux_packet_unref_contents(struct demux_packet *dp)
{
if (dp->avpacket) {
assert(!dp->is_cached);
av_packet_free(&dp->avpacket);
dp->buffer = NULL;
dp->len = 0;
}
}
static void packet_destroy(void *ptr)
{
struct demux_packet *dp = ptr;
demux_packet_unref_contents(dp);
}
static struct demux_packet *packet_create(void)
{
struct demux_packet *dp = talloc(NULL, struct demux_packet);
talloc_set_destructor(dp, packet_destroy);
*dp = (struct demux_packet) {
.pts = MP_NOPTS_VALUE,
.dts = MP_NOPTS_VALUE,
.duration = -1,
.pos = -1,
.start = MP_NOPTS_VALUE,
.end = MP_NOPTS_VALUE,
.stream = -1,
.avpacket = av_packet_alloc(),
.animated = -1,
};
MP_HANDLE_OOM(dp->avpacket);
return dp;
}
// This actually preserves only data and side data, not PTS/DTS/pos/etc.
// It also allows avpkt->data==NULL with avpkt->size!=0 - the libavcodec API
// does not allow it, but we do it to simplify new_demux_packet().
struct demux_packet *new_demux_packet_from_avpacket(struct AVPacket *avpkt)
{
if (avpkt->size > 1000000000)
return NULL;
struct demux_packet *dp = packet_create();
int r = -1;
if (avpkt->data) {
// We hope that this function won't need/access AVPacket input padding,
// because otherwise new_demux_packet_from() wouldn't work.
r = av_packet_ref(dp->avpacket, avpkt);
} else {
r = av_new_packet(dp->avpacket, avpkt->size);
}
if (r < 0) {
talloc_free(dp);
return NULL;
}
dp->buffer = dp->avpacket->data;
dp->len = dp->avpacket->size;
return dp;
}
// (buf must include proper padding)
struct demux_packet *new_demux_packet_from_buf(struct AVBufferRef *buf)
{
if (!buf)
return NULL;
if (buf->size > 1000000000)
return NULL;
struct demux_packet *dp = packet_create();
dp->avpacket->buf = av_buffer_ref(buf);
if (!dp->avpacket->buf) {
talloc_free(dp);
return NULL;
}
dp->avpacket->data = dp->buffer = buf->data;
dp->avpacket->size = dp->len = buf->size;
return dp;
}
// Input data doesn't need to be padded.
struct demux_packet *new_demux_packet_from(void *data, size_t len)
{
struct demux_packet *dp = new_demux_packet(len);
if (!dp)
return NULL;
memcpy(dp->avpacket->data, data, len);
return dp;
}
struct demux_packet *new_demux_packet(size_t len)
{
if (len > INT_MAX)
return NULL;
struct demux_packet *dp = packet_create();
int r = av_new_packet(dp->avpacket, len);
if (r < 0) {
talloc_free(dp);
return NULL;
}
dp->buffer = dp->avpacket->data;
dp->len = len;
return dp;
}
void demux_packet_shorten(struct demux_packet *dp, size_t len)
{
assert(len <= dp->len);
if (dp->len) {
dp->len = len;
memset(dp->buffer + dp->len, 0, AV_INPUT_BUFFER_PADDING_SIZE);
}
}
void free_demux_packet(struct demux_packet *dp)
{
talloc_free(dp);
}
void demux_packet_copy_attribs(struct demux_packet *dst, struct demux_packet *src)
{
dst->pts = src->pts;
dst->dts = src->dts;
dst->duration = src->duration;
dst->pos = src->pos;
dst->segmented = src->segmented;
dst->start = src->start;
dst->end = src->end;
dst->codec = src->codec;
dst->back_restart = src->back_restart;
dst->back_preroll = src->back_preroll;
dst->keyframe = src->keyframe;
dst->stream = src->stream;
}
struct demux_packet *demux_copy_packet(struct demux_packet *dp)
{
struct demux_packet *new = NULL;
if (dp->avpacket) {
new = new_demux_packet_from_avpacket(dp->avpacket);
} else {
// Some packets might be not created by new_demux_packet*().
new = new_demux_packet_from(dp->buffer, dp->len);
}
if (!new)
return NULL;
demux_packet_copy_attribs(new, dp);
return new;
}
#define ROUND_ALLOC(s) MP_ALIGN_UP((s), 16)
// Attempt to estimate the total memory consumption of the given packet.
// This is important if we store thousands of packets and not to exceed
// user-provided limits. Of course we can't know how much memory internal
// fragmentation of the libc memory allocator will waste.
// Note that this should return a "stable" value - e.g. if a new packet ref
// is created, this should return the same value with the new ref. (This
// implies the value is not exact and does not return the actual size of
// memory wasted due to internal fragmentation.)
size_t demux_packet_estimate_total_size(struct demux_packet *dp)
{
size_t size = ROUND_ALLOC(sizeof(struct demux_packet));
size += 8 * sizeof(void *); // ta overhead
size += 10 * sizeof(void *); // additional estimate for ta_ext_header
if (dp->avpacket) {
assert(!dp->is_cached);
size += ROUND_ALLOC(dp->len);
size += ROUND_ALLOC(sizeof(AVPacket));
size += 8 * sizeof(void *); // ta overhead
size += ROUND_ALLOC(sizeof(AVBufferRef));
size += ROUND_ALLOC(64); // upper bound estimate on sizeof(AVBuffer)
size += ROUND_ALLOC(dp->avpacket->side_data_elems *
sizeof(dp->avpacket->side_data[0]));
for (int n = 0; n < dp->avpacket->side_data_elems; n++)
size += ROUND_ALLOC(dp->avpacket->side_data[n].size);
}
return size;
}
int demux_packet_set_padding(struct demux_packet *dp, int start, int end)
{
if (!start && !end)
return 0;
if (!dp->avpacket)
return -1;
uint8_t *p = av_packet_new_side_data(dp->avpacket, AV_PKT_DATA_SKIP_SAMPLES, 10);
if (!p)
return -1;
AV_WL32(p + 0, start);
AV_WL32(p + 4, end);
return 0;
}
int demux_packet_add_blockadditional(struct demux_packet *dp, uint64_t id,
void *data, size_t size)
{
if (!dp->avpacket)
return -1;
switch (id) {
case MATROSKA_BLOCK_ADD_ID_TYPE_ITU_T_T35: {
static const uint8_t ITU_T_T35_COUNTRY_CODE_US = 0xB5;
static const uint16_t ITU_T_T35_PROVIDER_CODE_SMTPE = 0x3C;
if (size < 6)
break;
uint8_t *p = data;
uint8_t country_code = AV_RB8(p);
p += sizeof(country_code);
uint16_t provider_code = AV_RB16(p);
p += sizeof(provider_code);
if (country_code != ITU_T_T35_COUNTRY_CODE_US ||
provider_code != ITU_T_T35_PROVIDER_CODE_SMTPE)
break;
uint16_t provider_oriented_code = AV_RB16(p);
p += sizeof(provider_oriented_code);
uint8_t application_identifier = AV_RB8(p);
p += sizeof(application_identifier);
if (provider_oriented_code != 1 || application_identifier != 4)
break;
size_t hdrplus_size;
AVDynamicHDRPlus *hdrplus = av_dynamic_hdr_plus_alloc(&hdrplus_size);
MP_HANDLE_OOM(hdrplus);
if (av_dynamic_hdr_plus_from_t35(hdrplus, p, size - (p - (uint8_t *)data)) < 0 ||
av_packet_add_side_data(dp->avpacket, AV_PKT_DATA_DYNAMIC_HDR10_PLUS,
(uint8_t *)hdrplus, hdrplus_size) < 0)
{
av_free(hdrplus);
return -1;
}
return 0;
}
default:
break;
}
uint8_t *sd = av_packet_new_side_data(dp->avpacket,
AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL,
8 + size);
if (!sd)
return -1;
AV_WB64(sd, id);
if (size > 0)
memcpy(sd + 8, data, size);
return 0;
}
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