[FFmpeg-devel] [PATCH v2] avformat: add a concat protocol that takes a line break delimited list of resources
James Almer
jamrial at gmail.com
Sat Jun 26 19:56:57 EEST 2021
Suggested-by: ffmpeg at fb.com
Signed-off-by: James Almer <jamrial at gmail.com>
---
Updated documentation, and line breaks can now be part of the filename.
doc/protocols.texi | 33 +++++++++
libavformat/Makefile | 1 +
libavformat/concat.c | 146 ++++++++++++++++++++++++++++++++++++++++
libavformat/protocols.c | 1 +
4 files changed, 181 insertions(+)
diff --git a/doc/protocols.texi b/doc/protocols.texi
index ccdfb6e439..11de674225 100644
--- a/doc/protocols.texi
+++ b/doc/protocols.texi
@@ -215,6 +215,39 @@ ffplay concat:split1.mpeg\|split2.mpeg\|split3.mpeg
Note that you may need to escape the character "|" which is special for
many shells.
+ at section concatf
+
+Physical concatenation protocol using a line break delimited list of
+resources.
+
+Read and seek from many resources in sequence as if they were
+a unique resource.
+
+A URL accepted by this protocol has the syntax:
+ at example
+concatf:@var{URL}
+ at end example
+
+where @var{URL} is the url containing a line break delimited list of
+resources to be concatenated, each one possibly specifying a distinct
+protocol.
+
+For example to read a sequence of files @file{split1.mpeg},
+ at file{split2.mpeg}, @file{split3.mpeg} listed in separate lines within
+a file @file{split.txt} with @command{ffplay} use the command:
+ at example
+ffplay concatf:split.txt
+ at end example
+Where @file{split.txt} contains the lines:
+ at example
+split1.mpeg
+split2.mpeg
+split3.mpeg
+ at end example
+
+Note that if any of the entries in the list contain a line break as part
+of their name, you'll need to escape it with a preceding "\" character.
+
@section crypto
AES-encrypted stream reading protocol.
diff --git a/libavformat/Makefile b/libavformat/Makefile
index c9ef564523..caca95802a 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -616,6 +616,7 @@ OBJS-$(CONFIG_APPLEHTTP_PROTOCOL) += hlsproto.o
OBJS-$(CONFIG_BLURAY_PROTOCOL) += bluray.o
OBJS-$(CONFIG_CACHE_PROTOCOL) += cache.o
OBJS-$(CONFIG_CONCAT_PROTOCOL) += concat.o
+OBJS-$(CONFIG_CONCATF_PROTOCOL) += concat.o
OBJS-$(CONFIG_CRYPTO_PROTOCOL) += crypto.o
OBJS-$(CONFIG_DATA_PROTOCOL) += data_uri.o
OBJS-$(CONFIG_FFRTMPCRYPT_PROTOCOL) += rtmpcrypt.o rtmpdigest.o rtmpdh.o
diff --git a/libavformat/concat.c b/libavformat/concat.c
index 278afd997d..b66e3b9e01 100644
--- a/libavformat/concat.c
+++ b/libavformat/concat.c
@@ -22,9 +22,11 @@
*/
#include "libavutil/avstring.h"
+#include "libavutil/bprint.h"
#include "libavutil/mem.h"
#include "avformat.h"
+#include "avio_internal.h"
#include "url.h"
#define AV_CAT_SEPARATOR "|"
@@ -56,6 +58,7 @@ static av_cold int concat_close(URLContext *h)
return err < 0 ? -1 : 0;
}
+#if CONFIG_CONCAT_PROTOCOL
static av_cold int concat_open(URLContext *h, const char *uri, int flags)
{
char *node_uri = NULL;
@@ -124,6 +127,7 @@ static av_cold int concat_open(URLContext *h, const char *uri, int flags)
data->total_size = total_size;
return err;
}
+#endif
static int concat_read(URLContext *h, unsigned char *buf, int size)
{
@@ -188,6 +192,7 @@ static int64_t concat_seek(URLContext *h, int64_t pos, int whence)
return result;
}
+#if CONFIG_CONCAT_PROTOCOL
const URLProtocol ff_concat_protocol = {
.name = "concat",
.url_open = concat_open,
@@ -197,3 +202,144 @@ const URLProtocol ff_concat_protocol = {
.priv_data_size = sizeof(struct concat_data),
.default_whitelist = "concat,file,subfile",
};
+#endif
+
+#if CONFIG_CONCATF_PROTOCOL
+// Custom ff_read_line_to_bprint() implementation where line breaks can be
+// part of the line being read if escaped.
+static int64_t read_line_to_bprint(AVIOContext *s, AVBPrint *bp)
+{
+ int len, end;
+ int64_t read = 0;
+ char tmp[1024];
+ char c;
+
+ do {
+ len = 0;
+ do {
+ char escape = c = avio_r8(s);
+ if (c == '\\')
+ c = avio_r8(s);
+ end = (c == '\r' || c == '\n' || c == '\0');
+ if (end && escape == '\\') {
+ if (c != '\0') {
+ tmp[len++] = c;
+ end = 0;
+ } else
+ tmp[len++] = escape;
+ } else if (!end) {
+ if (escape == '\\') {
+ tmp[len++] = escape;
+ avio_skip(s, -1);
+ } else
+ tmp[len++] = c;
+ }
+ } while (!end && len < sizeof(tmp));
+ av_bprint_append_data(bp, tmp, len);
+ read += len;
+ } while (!end);
+
+ if (c == '\r' && avio_r8(s) != '\n' && !avio_feof(s))
+ avio_skip(s, -1);
+
+ if (!c && s->error)
+ return s->error;
+
+ if (!c && !read && avio_feof(s))
+ return AVERROR_EOF;
+
+ return read;
+}
+
+static av_cold int concatf_open(URLContext *h, const char *uri, int flags)
+{
+ AVBPrint bp;
+ struct concat_data *data = h->priv_data;
+ struct concat_nodes *nodes = NULL;
+ AVIOContext *in = NULL;
+ URLContext *uc;
+ int64_t size, total_size = 0;
+ unsigned int nodes_size = 0;
+ size_t i = 0;
+ int err = 0;
+
+ if (!av_strstart(uri, "concatf:", &uri)) {
+ av_log(h, AV_LOG_ERROR, "URL %s lacks prefix\n", uri);
+ return AVERROR(EINVAL);
+ }
+
+ /* handle input */
+ if (!*uri)
+ return AVERROR(ENOENT);
+
+ err = ffio_open_whitelist(&in, uri, AVIO_FLAG_READ, &h->interrupt_callback,
+ NULL, h->protocol_whitelist, h->protocol_blacklist);
+ if (err < 0)
+ return err;
+
+ av_bprint_init(&bp, 0, AV_BPRINT_SIZE_UNLIMITED);
+
+ for (i = 0; !avio_feof(in); i++) {
+ size_t len = i;
+
+ av_bprint_clear(&bp);
+ if ((err = read_line_to_bprint(in, &bp)) <= 0) {
+ if (err == 0 && i == 0)
+ err = AVERROR_INVALIDDATA;
+ else if (err == AVERROR_EOF)
+ err = 0;
+ break;
+ }
+
+ if (++len == SIZE_MAX / sizeof(*nodes)) {
+ err = AVERROR(ENAMETOOLONG);
+ break;
+ }
+
+ /* creating URLContext */
+ err = ffurl_open_whitelist(&uc, bp.str, flags,
+ &h->interrupt_callback, NULL, h->protocol_whitelist, h->protocol_blacklist, h);
+ if (err < 0)
+ break;
+
+ /* creating size */
+ if ((size = ffurl_size(uc)) < 0) {
+ ffurl_close(uc);
+ err = AVERROR(ENOSYS);
+ break;
+ }
+
+ nodes = av_fast_realloc(data->nodes, &nodes_size, sizeof(*nodes) * len);
+ if (!nodes) {
+ ffurl_close(uc);
+ err = AVERROR(ENOMEM);
+ break;
+ }
+ data->nodes = nodes;
+
+ /* assembling */
+ data->nodes[i].uc = uc;
+ data->nodes[i].size = size;
+ total_size += size;
+ }
+ avio_closep(&in);
+ av_bprint_finalize(&bp, NULL);
+ data->length = i;
+
+ if (err < 0)
+ concat_close(h);
+
+ data->total_size = total_size;
+ return err;
+}
+
+const URLProtocol ff_concatf_protocol = {
+ .name = "concatf",
+ .url_open = concatf_open,
+ .url_read = concat_read,
+ .url_seek = concat_seek,
+ .url_close = concat_close,
+ .priv_data_size = sizeof(struct concat_data),
+ .default_whitelist = "concatf,concat,file,subfile",
+};
+#endif
diff --git a/libavformat/protocols.c b/libavformat/protocols.c
index 4b6b1c8e98..7f08f151b6 100644
--- a/libavformat/protocols.c
+++ b/libavformat/protocols.c
@@ -27,6 +27,7 @@ extern const URLProtocol ff_async_protocol;
extern const URLProtocol ff_bluray_protocol;
extern const URLProtocol ff_cache_protocol;
extern const URLProtocol ff_concat_protocol;
+extern const URLProtocol ff_concatf_protocol;
extern const URLProtocol ff_crypto_protocol;
extern const URLProtocol ff_data_protocol;
extern const URLProtocol ff_ffrtmpcrypt_protocol;
--
2.32.0
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