diff options
Diffstat (limited to 'sub/lavc_conv.c')
| -rw-r--r-- | sub/lavc_conv.c | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/sub/lavc_conv.c b/sub/lavc_conv.c new file mode 100644 index 0000000000..21e54c04a7 --- /dev/null +++ b/sub/lavc_conv.c @@ -0,0 +1,280 @@ +/* + * This file is part of mpv. + * + * mpv is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 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 General Public License for more details. + * + * You should have received a copy of the GNU 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 "config.h" + +#include "talloc.h" +#include "common/msg.h" +#include "common/av_common.h" +#include "misc/bstr.h" +#include "sd.h" + +#define HAVE_AV_WEBVTT (LIBAVCODEC_VERSION_MICRO >= 100) + +struct lavc_conv { + struct mp_log *log; + AVCodecContext *avctx; + 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"; + return format; +} + +bool lavc_conv_supports_format(const char *format) +{ + format = get_lavc_format(format); + enum AVCodecID cid = mp_codec_to_av_codec_id(format); + AVCodec *codec = avcodec_find_decoder(cid); + const AVCodecDescriptor *desc = avcodec_descriptor_get(cid); + return codec && desc && desc->type == AVMEDIA_TYPE_SUBTITLE; +} + +// Disable style definitions generated by the libavcodec converter. +// We always want the user defined style instead. +static void disable_styles(bstr header) +{ + while (header.len) { + int n = bstr_find(header, bstr0("\nStyle: ")); + if (n < 0) + break; + header.start[n + 1] = '#'; // turn into a comment + header = bstr_cut(header, 2); + } +} + +struct lavc_conv *lavc_conv_create(struct mp_log *log, const char *codec_name, + char *extradata, int extradata_len) +{ + 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, codec_name); + AVCodecContext *avctx = NULL; + const char *fmt = get_lavc_format(priv->codec); + 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; + avctx->extradata_size = extradata_len; + avctx->extradata = talloc_memdup(priv, extradata, extradata_len); + if (avcodec_open2(avctx, codec, NULL) < 0) + goto error; + // Documented as "set by libavcodec", but there is no other way + avctx->time_base = (AVRational) {1, 1000}; + 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_free(avctx); + talloc_free(priv); + return NULL; +} + +char *lavc_conv_get_extradata(struct lavc_conv *priv) +{ + return priv->extradata; +} + +#if HAVE_AV_WEBVTT + +// 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; +#if !HAVE_AV_AVPACKET_INT64_DURATION + pkt->convergence_duration = in->convergence_duration; +#endif + return 0; +} + +#else + +static int parse_webvtt(AVPacket *in, AVPacket *pkt) +{ + return -1; +} + +#endif + +// Return a NULL-terminated list of ASS event lines. +char **lavc_conv_decode(struct lavc_conv *priv, struct demux_packet *packet) +{ + AVCodecContext *avctx = priv->avctx; + AVPacket pkt; + AVPacket parsed_pkt = {0}; + int ret, got_sub; + + avsubtitle_free(&priv->cur); + priv->cur_list[0] = NULL; + + mp_set_av_packet(&pkt, packet, &avctx->time_base); + + if (strcmp(priv->codec, "webvtt-webm") == 0) { + if (parse_webvtt(&pkt, &parsed_pkt) < 0) { + MP_ERR(priv, "Error parsing subtitle\n"); + goto done; + } + pkt = parsed_pkt; + } + + ret = avcodec_decode_subtitle2(avctx, &priv->cur, &got_sub, &pkt); + if (ret < 0) { + MP_ERR(priv, "Error decoding subtitle\n"); + } else if (got_sub) { + int num_cur = 0; + 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); + } + MP_TARRAY_APPEND(priv, priv->cur_list, num_cur, NULL); + } + +done: + av_packet_unref(&parsed_pkt); + 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) +{ + avcodec_close(priv->avctx); + av_free(priv->avctx); + talloc_free(priv); +} |