lavf: add a concat demuxer.

1 files changed, 221 insertions, 0 deletions

diff --git a/libavformat/concatdec.c b/libavformat/concatdec.c
new file mode 100644
index 0000000000..29233e2c8c
--- /dev/null
+++ b/libavformat/concatdec.c
@@ -0,0 +1,221 @@
+/*
+ * Copyright (c) 2012 Nicolas George
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/avstring.h"
+#include "avformat.h"
+#include "internal.h"
+
+typedef struct {
+    char *url;
+    int64_t start_time;
+    int64_t duration;
+} ConcatFile;
+
+typedef struct {
+    ConcatFile *files;
+    ConcatFile *cur_file;
+    unsigned nb_files;
+    AVFormatContext *avf;
+} ConcatContext;
+
+static int concat_probe(AVProbeData *probe)
+{
+    return 0;
+}
+
+static char *get_keyword(uint8_t **cursor)
+{
+    char *ret = *cursor += strspn(*cursor, SPACE_CHARS);
+    *cursor += strcspn(*cursor, SPACE_CHARS);
+    if (**cursor) {
+        *((*cursor)++) = 0;
+        *cursor += strspn(*cursor, SPACE_CHARS);
+    }
+    return ret;
+}
+
+#define FAIL(retcode) do { ret = (retcode); goto fail; } while(0)
+
+static int add_file(AVFormatContext *avf, char *filename, ConcatFile **rfile,
+                    unsigned *nb_files_alloc)
+{
+    ConcatContext *cat = avf->priv_data;
+    ConcatFile *file;
+    char *url;
+    size_t url_len;
+
+    url_len = strlen(avf->filename) + strlen(filename) + 16;
+    if (!(url = av_malloc(url_len)))
+        return AVERROR(ENOMEM);
+    ff_make_absolute_url(url, url_len, avf->filename, filename);
+    av_free(filename);
+
+    if (cat->nb_files >= *nb_files_alloc) {
+        unsigned n = FFMAX(*nb_files_alloc * 2, 16);
+        if (n <= cat->nb_files ||
+            !(cat->files = av_realloc_f(cat->files, n, sizeof(*cat->files))))
+            return AVERROR(ENOMEM);
+        *nb_files_alloc = n;
+    }
+
+    file = &cat->files[cat->nb_files++];
+    memset(file, 0, sizeof(*file));
+    *rfile = file;
+
+    file->url        = url;
+    file->start_time = AV_NOPTS_VALUE;
+    file->duration   = AV_NOPTS_VALUE;
+
+    return 0;
+}
+
+static int open_file(AVFormatContext *avf, unsigned fileno)
+{
+    ConcatContext *cat = avf->priv_data;
+    ConcatFile *file = &cat->files[fileno];
+    int ret;
+
+    if ((ret = avformat_open_input(&cat->avf, file->url, NULL, NULL)) < 0 ||
+        (ret = avformat_find_stream_info(cat->avf, NULL)) < 0) {
+        av_log(avf, AV_LOG_ERROR, "Impossible to open '%s'\n", file->url);
+        return ret;
+    }
+    cat->cur_file = file;
+    if (file->start_time == AV_NOPTS_VALUE)
+        file->start_time = !fileno ? 0 :
+                           cat->files[fileno - 1].start_time +
+                           cat->files[fileno - 1].duration;
+    return 0;
+}
+
+static int concat_read_close(AVFormatContext *avf)
+{
+    ConcatContext *cat = avf->priv_data;
+    unsigned i;
+
+    if (cat->avf)
+        avformat_close_input(&cat->avf);
+    for (i = 0; i < cat->nb_files; i++)
+        av_freep(&cat->files[i].url);
+    av_freep(&cat->files);
+    return 0;
+}
+
+static int concat_read_header(AVFormatContext *avf)
+{
+    ConcatContext *cat = avf->priv_data;
+    uint8_t buf[4096];
+    uint8_t *cursor, *keyword;
+    int ret, line = 0, i;
+    unsigned nb_files_alloc = 0;
+    ConcatFile *file = NULL;
+    AVStream *st, *source_st;
+
+    while (1) {
+        if ((ret = ff_get_line(avf->pb, buf, sizeof(buf))) <= 0)
+            break;
+        line++;
+        cursor = buf;
+        keyword = get_keyword(&cursor);
+        if (!*keyword || *keyword == '#')
+            continue;
+
+        if (!strcmp(keyword, "file")) {
+            char *filename = av_get_token((const char **)&cursor, SPACE_CHARS);
+            if (!filename) {
+                av_log(avf, AV_LOG_ERROR, "Line %d: filename required\n", line);
+                FAIL(AVERROR_INVALIDDATA);
+            }
+            if ((ret = add_file(avf, filename, &file, &nb_files_alloc)) < 0)
+                FAIL(ret);
+        } else {
+            av_log(avf, AV_LOG_ERROR, "Line %d: unknown keyword '%s'\n",
+                   line, keyword);
+            FAIL(AVERROR_INVALIDDATA);
+        }
+    }
+    if (ret < 0)
+        FAIL(ret);
+
+    if ((ret = open_file(avf, 0)) < 0)
+        FAIL(ret);
+    for (i = 0; i < cat->avf->nb_streams; i++) {
+        if (!(st = avformat_new_stream(avf, NULL)))
+            FAIL(AVERROR(ENOMEM));
+        source_st = cat->avf->streams[i];
+        if ((ret = avcodec_copy_context(st->codec, source_st->codec)) < 0)
+            FAIL(ret);
+        st->r_frame_rate        = source_st->r_frame_rate;
+        st->avg_frame_rate      = source_st->avg_frame_rate;
+        st->time_base           = source_st->time_base;
+        st->sample_aspect_ratio = source_st->sample_aspect_ratio;
+    }
+
+    return 0;
+
+fail:
+    concat_read_close(avf);
+    return ret;
+}
+
+static int open_next_file(AVFormatContext *avf)
+{
+    ConcatContext *cat = avf->priv_data;
+    unsigned fileno = cat->cur_file - cat->files;
+
+    if (cat->cur_file->duration == AV_NOPTS_VALUE)
+        cat->cur_file->duration = cat->avf->duration;
+
+    if (++fileno >= cat->nb_files)
+        return AVERROR_EOF;
+    avformat_close_input(&cat->avf);
+    return open_file(avf, fileno);
+}
+
+static int concat_read_packet(AVFormatContext *avf, AVPacket *pkt)
+{
+    ConcatContext *cat = avf->priv_data;
+    int ret;
+    int64_t delta;
+
+    while (1) {
+        if ((ret = av_read_frame(cat->avf, pkt)) != AVERROR_EOF ||
+            (ret = open_next_file(avf)) < 0)
+            break;
+    }
+    delta = av_rescale_q(cat->cur_file->start_time - cat->avf->start_time,
+                         AV_TIME_BASE_Q,
+                         cat->avf->streams[pkt->stream_index]->time_base);
+    if (pkt->pts != AV_NOPTS_VALUE)
+        pkt->pts += delta;
+    if (pkt->dts != AV_NOPTS_VALUE)
+        pkt->dts += delta;
+    return ret;
+}
+
+AVInputFormat ff_concat_demuxer = {
+    .name           = "concat",
+    .long_name      = NULL_IF_CONFIG_SMALL("Virtual concatenation script"),
+    .priv_data_size = sizeof(ConcatContext),
+    .read_probe     = concat_probe,
+    .read_header    = concat_read_header,
+    .read_packet    = concat_read_packet,
+    .read_close     = concat_read_close,
+};