[FFmpeg-devel] [PATCH] lavf/tee: add support for bitstream filtering
Nicolas George
nicolas.george at normalesup.org
Sun Aug 4 11:53:36 CEST 2013
Le sextidi 16 thermidor, an CCXXI, Stefano Sabatini a écrit :
> Updated with various fixes. I'm still making my mind about adopting a
> different syntax.
> --
> FFmpeg = Fast & Foolish Marvellous Powerful Everlasting Guru
> >From 35fed58f67befbdf9067a03110dc87d47be34b7c Mon Sep 17 00:00:00 2001
> From: Stefano Sabatini <stefasab at gmail.com>
> Date: Fri, 5 Jul 2013 18:33:30 +0200
> Subject: [PATCH] lavf/tee: add support for bitstream filtering
>
> This allows to apply different bitstream filters to different outputs,
> with no need to trancode.
Note: if you are not transcoding, -f tee is not necessary, -c copy will work
just fine. -f tee, IMHO, is most useful when transcoding with expensive
codecs.
>
> TODO: bump minor
> ---
> doc/muxers.texi | 25 ++++++-
> libavformat/tee.c | 201 +++++++++++++++++++++++++++++++++++++++++++++++++++---
> 2 files changed, 216 insertions(+), 10 deletions(-)
>
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index b0dc7e6..7c5a1c8 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -818,11 +818,34 @@ leading or trailing spaces or any special character, it must be
> escaped (see the ``Quoting and escaping'' section in the ffmpeg-utils
> manual).
>
> -Options can be specified for each slave by prepending them as a list of
> +Muxer options can be specified for each slave by prepending them as a list of
> @var{key}=@var{value} pairs separated by ':', between square brackets. If
> the options values contain a special character or the ':' separator, they
> must be escaped; note that this is a second level escaping.
>
> +The following special options are also recognized:
> + at table @option
> + at item f
> +Specify the format name. Useful if it cannot be guessed from the
> +output name suffix.
> +
> + at item bsfs
> +Specify a list of bitstream filters to apply to the specified
> +output. It is possible to specify to which streams a given bitstream
> +filter applies, by appending a stream specifier to a bitstream filter
> +followed by a "+". If the stream specifier is not specified, it will
> +be applied to all streams in the output.
> +
> +Several bitstream filters can be specified, separated each other by
I am not completely sure, but I believe that it should be "separated from
each other"; it could be simply "separated by".
> +",".
> +
> +The BNF description of the bitstream filters specification is given by:
> + at example
> + at var{BSF} ::= @var{BSF_NAME}[+ at var{STREAM_SPECIFIER}]
> + at var{BSFS} ::= @var{BSF}[, at var{BSFS}]
> + at end example
> + at end table
> +
> Example: encode something and both archive it in a WebM file and stream it
> as MPEG-TS over UDP (the streams need to be explicitly mapped):
>
> diff --git a/libavformat/tee.c b/libavformat/tee.c
> index 7b8b371..90947c7 100644
> --- a/libavformat/tee.c
> +++ b/libavformat/tee.c
> @@ -27,10 +27,16 @@
>
> #define MAX_SLAVES 16
>
> +typedef struct {
> + AVFormatContext *fmt_ctx;
> + AVBitStreamFilterContext **bsf_ctxs; ///< bitstream filters per stream
> +} TeeSlave;
> +
> typedef struct TeeContext {
> const AVClass *class;
> unsigned nb_slaves;
> - AVFormatContext *slaves[MAX_SLAVES];
> + TeeSlave slaves[MAX_SLAVES];
> + char *bsfs;
> } TeeContext;
>
> static const char *const slave_delim = "|";
> @@ -82,13 +88,98 @@ fail:
> return ret;
> }
>
> -static int open_slave(AVFormatContext *avf, char *slave, AVFormatContext **ravf)
> +/**
> + * Parse bitstream filter, in the form:
> + * BSF ::= BSF_NAME[+STREAM_SPECIFIER]
> + */
> +static int parse_bsf(void *log_ctx, char *bsf,
> + AVFormatContext *fmt_ctx,
> + AVBitStreamFilterContext **bsf_ctxs)
> +{
> + int i, ret = 0;
> + char *bsf1 = av_strdup(bsf);
> + char *bsf_name, *spec;
> +
> + if (!bsf1)
> + return AVERROR(ENOMEM);
> + bsf_name = av_strtok(bsf1, "+", &spec);
> +
> + /* select the streams matched by the specifier */
> + for (i = 0; i < fmt_ctx->nb_streams; i++) {
> + AVBitStreamFilterContext *bsf_ctx;
> +
> + if (spec && spec[0]) {
> + ret = avformat_match_stream_specifier(fmt_ctx, fmt_ctx->streams[i], spec);
> + if (ret < 0) {
> + av_log(log_ctx, AV_LOG_ERROR,
> + "Invalid stream specifier for bitstream filter '%s'\n", bsf);
> + goto end;
> + }
> +
> + if (ret == 0) /* no match */
> + continue;
> + }
> +
> + bsf_ctx = av_bitstream_filter_init(bsf_name);
> + if (!bsf_ctx) {
> + av_log(log_ctx, AV_LOG_ERROR,
> + "Cannot create bitstream filter with name '%s' for stream %d, "
> + "unknown filter or internal error happened\n",
> + bsf_name, i);
> + ret = AVERROR_UNKNOWN;
> + goto end;
> + }
> +
> + /* append bsf context to the list of per-stream bsf contexts */
> + if (!bsf_ctxs[i]) {
> + bsf_ctxs[i] = bsf_ctx;
> + } else {
> + AVBitStreamFilterContext *bsf_ctx1 = bsf_ctxs[i];
> + while (bsf_ctx1->next)
> + bsf_ctx1 = bsf_ctx1->next;
> + bsf_ctx1->next = bsf_ctx;
> + }
> + }
> +
> +end:
> + av_free(bsf1);
> + return ret;
> +}
> +
> +/**
> + * Parse list of bitstream filters in the form:
> + * BSFS ::= BSF[,BSFS]
> + */
> +static int parse_slave_bsfs(void *log_ctx, char *slave_bsfs,
> + AVFormatContext *fmt_ctx,
> + AVBitStreamFilterContext **bsf_ctx)
> +{
> + char *bsf, *slave_bsfs1 = av_strdup(slave_bsfs);
> + char *saveptr, *buf = slave_bsfs1;
> + int ret;
> +
> + if (!slave_bsfs1)
> + return AVERROR(ENOMEM);
> +
> + while (bsf = av_strtok(buf, ",", &saveptr)) {
> + buf = NULL;
> + ret = parse_bsf(log_ctx, bsf, fmt_ctx, bsf_ctx);
> + if (ret < 0)
> + goto end;
> + }
> +
> +end:
> + av_free(slave_bsfs1);
> + return ret;
> +}
> +
> +static int open_slave(AVFormatContext *avf, char *slave, TeeSlave *tee_slave)
> {
> int i, ret;
> AVDictionary *options = NULL;
> AVDictionaryEntry *entry;
> char *filename;
> - char *format = NULL;
> + char *format = NULL, *bsfs = NULL;
> AVFormatContext *avf2 = NULL;
> AVStream *st, *st2;
>
> @@ -99,6 +190,11 @@ static int open_slave(AVFormatContext *avf, char *slave, AVFormatContext **ravf)
> entry->value = NULL; /* prevent it from being freed */
> av_dict_set(&options, "f", NULL, 0);
> }
> + if ((entry = av_dict_get(options, "bsfs", NULL, 0))) {
> + bsfs = entry->value;
> + entry->value = NULL; /* prevent it from being freed */
> + av_dict_set(&options, "bsfs", NULL, 0);
> + }
>
> ret = avformat_alloc_output_context2(&avf2, NULL, format, filename);
> if (ret < 0)
> @@ -138,6 +234,7 @@ static int open_slave(AVFormatContext *avf, char *slave, AVFormatContext **ravf)
> slave, av_err2str(ret));
> goto fail;
> }
> +
> if (options) {
> entry = NULL;
> while ((entry = av_dict_get(options, "", entry, AV_DICT_IGNORE_SUFFIX)))
> @@ -146,7 +243,17 @@ static int open_slave(AVFormatContext *avf, char *slave, AVFormatContext **ravf)
> goto fail;
> }
>
> - *ravf = avf2;
> + tee_slave->fmt_ctx = avf2;
> + tee_slave->bsf_ctxs = av_calloc(avf2->nb_streams, sizeof(TeeSlave));
> + if (!tee_slave->bsf_ctxs)
> + return AVERROR(ENOMEM);
> + memset(tee_slave->bsf_ctxs, 0, avf2->nb_streams * sizeof(TeeSlave));
> +
> + /* generate the array of bitstream filters */
> + if (bsfs) {
> + if ((ret = parse_slave_bsfs(avf, bsfs, avf2, tee_slave->bsf_ctxs)) < 0)
> + return ret;
> + }
I suspect bsfs leaks here. And since it belongs exclusively to this code,
you could remove all the av_strdup() in the parsing code, that would make it
simpler (or do you have a reason not to?).
> return 0;
>
> fail:
> @@ -158,14 +265,47 @@ static void close_slaves(AVFormatContext *avf)
> {
> TeeContext *tee = avf->priv_data;
> AVFormatContext *avf2;
> - unsigned i;
> + unsigned i, j;
>
> for (i = 0; i < tee->nb_slaves; i++) {
> - avf2 = tee->slaves[i];
> + avf2 = tee->slaves[i].fmt_ctx;
> +
> + for (j = 0; j < avf2->nb_streams; j++) {
> + AVBitStreamFilterContext *bsf_ctx = tee->slaves[i].bsf_ctxs[j];
> + while (bsf_ctx) {
> + bsf_ctx = bsf_ctx->next;
> + av_bitstream_filter_close(bsf_ctx);
> + }
> + }
> +
> avio_close(avf2->pb);
> avf2->pb = NULL;
> avformat_free_context(avf2);
> - tee->slaves[i] = NULL;
> + tee->slaves[i].fmt_ctx = NULL;
> + }
> +}
> +
> +static void log_slave(TeeSlave *slave, void *log_ctx, int log_level)
> +{
> + int i;
> + av_log(log_ctx, log_level, "filename:'%s' format:%s\n",
> + slave->fmt_ctx->filename, slave->fmt_ctx->oformat->name);
> + for (i = 0; i < slave->fmt_ctx->nb_streams; i++) {
> + AVStream *st = slave->fmt_ctx->streams[i];
> + AVBitStreamFilterContext *bsf_ctx = slave->bsf_ctxs[i];
> +
> + av_log(log_ctx, log_level, " stream:%d codec:%s type:%s",
> + i, avcodec_get_name(st->codec->codec_id),
> + av_get_media_type_string(st->codec->codec_type));
> + if (bsf_ctx) {
> + av_log(log_ctx, log_level, " bsfs:");
> + while (bsf_ctx) {
> + av_log(log_ctx, log_level, "%s%s",
> + bsf_ctx->filter->name, bsf_ctx->next ? "," : "");
> + bsf_ctx = bsf_ctx->next;
> + }
> + }
> + av_log(log_ctx, log_level, "\n");
> }
> }
>
> @@ -195,6 +335,7 @@ static int tee_write_header(AVFormatContext *avf)
> for (i = 0; i < nb_slaves; i++) {
> if ((ret = open_slave(avf, slaves[i], &tee->slaves[i])) < 0)
> goto fail;
> + log_slave(&tee->slaves[i], avf, AV_LOG_VERBOSE);
> av_freep(&slaves[i]);
> }
>
> @@ -208,6 +349,46 @@ fail:
> return ret;
> }
>
> +static int filter_packet(void *log_ctx, AVPacket *pkt,
> + AVFormatContext *fmt_ctx, AVBitStreamFilterContext *bsf_ctx)
> +{
> + AVCodecContext *enc_ctx = fmt_ctx->streams[pkt->stream_index]->codec;
> + int ret;
> +
> + while (bsf_ctx) {
> + AVPacket new_pkt = *pkt;
> + ret = av_bitstream_filter_filter(bsf_ctx, enc_ctx, NULL,
> + &new_pkt.data, &new_pkt.size,
> + pkt->data, pkt->size,
> + pkt->flags & AV_PKT_FLAG_KEY);
> + if (ret == 0 && new_pkt.data != pkt->data && new_pkt.destruct) {
> + if ((ret = av_copy_packet(&new_pkt, pkt)) < 0)
> + break;
> + ret = 1;
> + }
> +
> + if (ret > 0) {
> + av_free_packet(pkt);
> + new_pkt.buf = av_buffer_create(new_pkt.data, new_pkt.size,
> + av_buffer_default_free, NULL, 0);
> + if (!new_pkt.buf)
> + break;
> + }
> + *pkt = new_pkt;
> +
> + bsf_ctx = bsf_ctx->next;
> + }
> +
> + if (ret < 0) {
> + av_log(log_ctx, AV_LOG_ERROR,
> + "Failed to filter bitstream with filter %s for stream %d in file '%s' with codec %s\n",
> + bsf_ctx->filter->name, pkt->stream_index, fmt_ctx->filename,
> + avcodec_get_name(enc_ctx->codec_id));
> + }
> +
> + return ret;
> +}
> +
> static int tee_write_trailer(AVFormatContext *avf)
> {
> TeeContext *tee = avf->priv_data;
> @@ -216,7 +397,7 @@ static int tee_write_trailer(AVFormatContext *avf)
> unsigned i;
>
> for (i = 0; i < tee->nb_slaves; i++) {
> - avf2 = tee->slaves[i];
> + avf2 = tee->slaves[i].fmt_ctx;
> if ((ret = av_write_trailer(avf2)) < 0)
> if (!ret_all)
> ret_all = ret;
> @@ -241,7 +422,7 @@ static int tee_write_packet(AVFormatContext *avf, AVPacket *pkt)
> AVRational tb, tb2;
>
> for (i = 0; i < tee->nb_slaves; i++) {
> - avf2 = tee->slaves[i];
> + avf2 = tee->slaves[i].fmt_ctx;
> s = pkt->stream_index;
> if (s >= avf2->nb_streams) {
> if (!ret_all)
> @@ -259,6 +440,8 @@ static int tee_write_packet(AVFormatContext *avf, AVPacket *pkt)
> pkt2.pts = av_rescale_q(pkt->pts, tb, tb2);
> pkt2.dts = av_rescale_q(pkt->dts, tb, tb2);
> pkt2.duration = av_rescale_q(pkt->duration, tb, tb2);
> +
> + filter_packet(avf2, &pkt2, avf2, tee->slaves[i].bsf_ctxs[s]);
> if ((ret = av_interleaved_write_frame(avf2, &pkt2)) < 0)
> if (!ret_all)
> ret_all = ret;
No more remarks for now.
Regards,
--
Nicolas George
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