[FFmpeg-devel] [PATCH] avformat: add a concat protocol that takes a line break delimited list of resources
James Almer
jamrial at gmail.com
Thu Jun 24 18:08:42 EEST 2021
On 6/24/2021 11:59 AM, Nicolas George wrote:
> 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?
Yes, since it's used to delimit files in the list.
>
>> + 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?
At least on Windows a backslash is not allowed on file names (Alongside
many other such characters), but apostrophes are, and they effectively
need to be escaped. Thanks for catching it.
I'll add a mention in the doxy about the need to escape certain characters.
>
>> + 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,
>
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