[FFmpeg-devel] [PATCH] avformat: add a concat protocol that takes a line break delimited list of resources
Nicolas George
george at nsup.org
Thu Jun 24 17:59:43 EEST 2021
James Almer (12021-06-23):
> Suggested-by: ffmpeg at fb.com
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> doc/protocols.texi | 30 +++++++++++
> libavformat/Makefile | 1 +
> libavformat/concat.c | 111 ++++++++++++++++++++++++++++++++++++++++
> libavformat/protocols.c | 1 +
> 4 files changed, 143 insertions(+)
>
> diff --git a/doc/protocols.texi b/doc/protocols.texi
> index ccdfb6e439..2b8ce1b7d5 100644
> --- a/doc/protocols.texi
> +++ b/doc/protocols.texi
> @@ -215,6 +215,36 @@ 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
> +
> @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..d224b51db0 100644
> --- a/libavformat/concat.c
> +++ b/libavformat/concat.c
> @@ -22,9 +22,12 @@
> */
>
> #include "libavutil/avstring.h"
> +#include "libavutil/bprint.h"
> #include "libavutil/mem.h"
>
> #include "avformat.h"
> +#include "avio_internal.h"
> +#include "internal.h"
> #include "url.h"
>
> #define AV_CAT_SEPARATOR "|"
> @@ -56,6 +59,7 @@ 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 +128,7 @@ 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 +193,7 @@ 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 +203,108 @@ const URLProtocol ff_concat_protocol = {
> .priv_data_size = sizeof(struct concat_data),
> .default_whitelist = "concat,file,subfile",
> };
> +#endif
> +
> +#if CONFIG_CONCATF_PROTOCOL
> +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;
> + char *node_uri = NULL;
> + 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++) {
> + uint8_t *cursor;
> + size_t len = i;
> +
> + if ((err = ff_read_line_to_bprint_overwrite(in, &bp)) <= 0) {
Are we ok that file with a \n in their name will not be supported?
> + if (err == 0 && i == 0)
> + err = AVERROR_INVALIDDATA;
> + else if (err == AVERROR_EOF)
> + err = 0;
> + break;
> + }
> +
> + cursor = bp.str;
> + node_uri = av_get_token((const char **)&cursor, "\t\r\n");
Does this protocol work with file names that contain an apostrophe or an
actual backslash?
> + if (!node_uri) {
> + err = AVERROR(ENOMEM);
> + break;
> + }
> +
> + if (++len == SIZE_MAX / sizeof(*nodes)) {
> + av_freep(&node_uri);
> + err = AVERROR(ENAMETOOLONG);
> + break;
> + }
> +
> + /* creating URLContext */
> + err = ffurl_open_whitelist(&uc, node_uri, flags,
> + &h->interrupt_callback, NULL, h->protocol_whitelist, h->protocol_blacklist, h);
> + av_freep(&node_uri);
> + 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;
Regards,
--
Nicolas George
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