sub: rename sd_lavc_conv.c to lavc_conv.c

The previous commit turned sd_lavc_conv from a sd_driver to
free-standing functions. Do the rename to reflect this change
separately to avoid confusing git's content tracking. (Or did
git solve this, making separating renames and content changes
unnecessary?)

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);
+}