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mpv/sub/lavc_conv.c
Jan Ekström e20b645611 sub/lavc_conv: properly fill avctx with codecpar values at init 
This way we receive such minor details as the profile (necessary for
ARIB captions, among others) during init. This enables decoders
to switch between ARIB caption profile A and profile C streams.
2023-03-14 23:59:47 +02:00

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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 <assert.h>
#include <libavcodec/avcodec.h>
#include <libavutil/intreadwrite.h>
#include <libavutil/common.h>
#include <libavutil/opt.h>
#include "mpv_talloc.h"
#include "common/msg.h"
#include "common/av_common.h"
#include "demux/stheader.h"
#include "misc/bstr.h"
#include "sd.h"
struct lavc_conv {
struct mp_log *log;
AVCodecContext *avctx;
AVPacket *avpkt;
AVPacket *avpkt_vtt;
char *codec;
char *extradata;
AVSubtitle cur;
char **cur_list;
};
static const char *get_lavc_format(const char *format)
{
// For the hack involving parse_webvtt().
if (format && strcmp(format, "webvtt-webm") == 0)
format = "webvtt";
// Most text subtitles are srt/html style anyway.
if (format && strcmp(format, "text") == 0)
format = "subrip";
return format;
}
// Disable style definitions generated by the libavcodec converter.
// We always want the user defined style instead.
static void disable_styles(bstr header)
{
bstr style = bstr0("\nStyle: ");
while (header.len) {
int n = bstr_find(header, style);
if (n < 0)
break;
header.start[n + 1] = '#'; // turn into a comment
header = bstr_cut(header, n + style.len);
}
}
struct lavc_conv *lavc_conv_create(struct mp_log *log,
const struct mp_codec_params *mp_codec)
{
struct lavc_conv *priv = talloc_zero(NULL, struct lavc_conv);
priv->log = log;
priv->cur_list = talloc_array(priv, char*, 0);
priv->codec = talloc_strdup(priv, mp_codec->codec);
AVCodecContext *avctx = NULL;
AVDictionary *opts = NULL;
const char *fmt = get_lavc_format(priv->codec);
const AVCodec *codec = avcodec_find_decoder(mp_codec_to_av_codec_id(fmt));
if (!codec)
goto error;
avctx = avcodec_alloc_context3(codec);
if (!avctx)
goto error;
if (mp_set_avctx_codec_headers(avctx, mp_codec) < 0)
goto error;
priv->avpkt = av_packet_alloc();
priv->avpkt_vtt = av_packet_alloc();
if (!priv->avpkt || !priv->avpkt_vtt)
goto error;
#if LIBAVCODEC_VERSION_MAJOR < 59
av_dict_set(&opts, "sub_text_format", "ass", 0);
#endif
av_dict_set(&opts, "flags2", "+ass_ro_flush_noop", 0);
if (strcmp(priv->codec, "eia_608") == 0)
av_dict_set(&opts, "real_time", "1", 0);
if (avcodec_open2(avctx, codec, &opts) < 0)
goto error;
av_dict_free(&opts);
// Documented as "set by libavcodec", but there is no other way
avctx->time_base = (AVRational) {1, 1000};
avctx->pkt_timebase = avctx->time_base;
avctx->sub_charenc_mode = FF_SUB_CHARENC_MODE_IGNORE;
priv->avctx = avctx;
priv->extradata = talloc_strndup(priv, avctx->subtitle_header,
avctx->subtitle_header_size);
disable_styles(bstr0(priv->extradata));
return priv;
error:
MP_FATAL(priv, "Could not open libavcodec subtitle converter\n");
av_dict_free(&opts);
av_free(avctx);
mp_free_av_packet(&priv->avpkt);
mp_free_av_packet(&priv->avpkt_vtt);
talloc_free(priv);
return NULL;
}
char *lavc_conv_get_extradata(struct lavc_conv *priv)
{
return priv->extradata;
}
// FFmpeg WebVTT packets are pre-parsed in some way. The FFmpeg Matroska
// demuxer does this on its own. In order to free our demuxer_mkv.c from
// codec-specific crud, we do this here.
// Copied from libavformat/matroskadec.c (FFmpeg 818ebe9 / 2013-08-19)
// License: LGPL v2.1 or later
// Author header: The FFmpeg Project
// Modified in some ways.
static int parse_webvtt(AVPacket *in, AVPacket *pkt)
{
uint8_t *id, *settings, *text, *buf;
int id_len, settings_len, text_len;
uint8_t *p, *q;
int err;
uint8_t *data = in->data;
int data_len = in->size;
if (data_len <= 0)
return AVERROR_INVALIDDATA;
p = data;
q = data + data_len;
id = p;
id_len = -1;
while (p < q) {
if (*p == '\r' || *p == '\n') {
id_len = p - id;
if (*p == '\r')
p++;
break;
}
p++;
}
if (p >= q || *p != '\n')
return AVERROR_INVALIDDATA;
p++;
settings = p;
settings_len = -1;
while (p < q) {
if (*p == '\r' || *p == '\n') {
settings_len = p - settings;
if (*p == '\r')
p++;
break;
}
p++;
}
if (p >= q || *p != '\n')
return AVERROR_INVALIDDATA;
p++;
text = p;
text_len = q - p;
while (text_len > 0) {
const int len = text_len - 1;
const uint8_t c = p[len];
if (c != '\r' && c != '\n')
break;
text_len = len;
}
if (text_len <= 0)
return AVERROR_INVALIDDATA;
err = av_new_packet(pkt, text_len);
if (err < 0)
return AVERROR(err);
memcpy(pkt->data, text, text_len);
if (id_len > 0) {
buf = av_packet_new_side_data(pkt,
AV_PKT_DATA_WEBVTT_IDENTIFIER,
id_len);
if (buf == NULL) {
av_packet_unref(pkt);
return AVERROR(ENOMEM);
}
memcpy(buf, id, id_len);
}
if (settings_len > 0) {
buf = av_packet_new_side_data(pkt,
AV_PKT_DATA_WEBVTT_SETTINGS,
settings_len);
if (buf == NULL) {
av_packet_unref(pkt);
return AVERROR(ENOMEM);
}
memcpy(buf, settings, settings_len);
}
pkt->pts = in->pts;
pkt->duration = in->duration;
return 0;
}
// Return a NULL-terminated list of ASS event lines and have
// the AVSubtitle display PTS and duration set to input
// double variables.
char **lavc_conv_decode(struct lavc_conv *priv, struct demux_packet *packet,
double *sub_pts, double *sub_duration)
{
AVCodecContext *avctx = priv->avctx;
AVPacket *curr_pkt = priv->avpkt;
int ret, got_sub;
int num_cur = 0;
avsubtitle_free(&priv->cur);
mp_set_av_packet(priv->avpkt, packet, &avctx->time_base);
if (priv->avpkt->pts < 0)
priv->avpkt->pts = 0;
if (strcmp(priv->codec, "webvtt-webm") == 0) {
if (parse_webvtt(priv->avpkt, priv->avpkt_vtt) < 0) {
MP_ERR(priv, "Error parsing subtitle\n");
goto done;
}
curr_pkt = priv->avpkt_vtt;
}
ret = avcodec_decode_subtitle2(avctx, &priv->cur, &got_sub, curr_pkt);
if (ret < 0) {
MP_ERR(priv, "Error decoding subtitle\n");
} else if (got_sub) {
*sub_pts = packet->pts + mp_pts_from_av(priv->cur.start_display_time,
&avctx->time_base);
*sub_duration = priv->cur.end_display_time == UINT32_MAX ?
UINT32_MAX :
mp_pts_from_av(priv->cur.end_display_time -
priv->cur.start_display_time,
&avctx->time_base);
for (int i = 0; i < priv->cur.num_rects; i++) {
if (priv->cur.rects[i]->w > 0 && priv->cur.rects[i]->h > 0)
MP_WARN(priv, "Ignoring bitmap subtitle.\n");
char *ass_line = priv->cur.rects[i]->ass;
if (!ass_line)
continue;
MP_TARRAY_APPEND(priv, priv->cur_list, num_cur, ass_line);
}
}
done:
av_packet_unref(priv->avpkt_vtt);
MP_TARRAY_APPEND(priv, priv->cur_list, num_cur, NULL);
return priv->cur_list;
}
void lavc_conv_reset(struct lavc_conv *priv)
{
avcodec_flush_buffers(priv->avctx);
}
void lavc_conv_uninit(struct lavc_conv *priv)
{
avsubtitle_free(&priv->cur);
avcodec_free_context(&priv->avctx);
mp_free_av_packet(&priv->avpkt);
mp_free_av_packet(&priv->avpkt_vtt);
talloc_free(priv);
}
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