PR #21609 opened by mkver URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21609 Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21609.patch
>From d845f9b7475c76da897aad5dfbab5c76e2a4df48 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt <[email protected]> Date: Fri, 30 Jan 2026 14:25:00 +0100 Subject: [PATCH 1/2] avformat/cafenc: Simplify writing pakt box Assemble it already in caf_write_packet(). This has the advantage of reducing the amount of buffers used; it also allows to avoid a seek when writing the trailer and avoids function call overhead (for the avio_w8(); it also reduces codesize). Signed-off-by: Andreas Rheinhardt <[email protected]> --- libavformat/cafenc.c | 98 +++++++++++++++----------------------------- 1 file changed, 34 insertions(+), 64 deletions(-) diff --git a/libavformat/cafenc.c b/libavformat/cafenc.c index 5f2d79e0a7..4542cc7b04 100644 --- a/libavformat/cafenc.c +++ b/libavformat/cafenc.c @@ -19,6 +19,8 @@ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ +#include <stdint.h> + #include "avformat.h" #include "caf.h" #include "isom.h" @@ -36,10 +38,9 @@ typedef struct { int64_t packets; uint32_t frame_size; - uint32_t *byte_size_buffer; - uint32_t *frame_size_buffer; - unsigned byte_size_buffer_sz; - unsigned frame_size_buffer_sz; + uint8_t *pakt_buf; + unsigned pakt_buf_size; + unsigned pakt_buf_alloc_size; } CAFContext; static uint32_t codec_flags(enum AVCodecID codec_id) { @@ -235,39 +236,39 @@ static int caf_write_header(AVFormatContext *s) return 0; } +static uint8_t *put_variable_length_num(uint8_t *buf, uint32_t num) +{ + for (int j = 4; j > 0; j--) { + unsigned top = num >> j * 7; + if (top) + *(buf++) = top | 128; + } + *(buf++) = num & 127; + return buf; +} + static int caf_write_packet(AVFormatContext *s, AVPacket *pkt) { CAFContext *caf = s->priv_data; AVStream *const st = s->streams[0]; if (!st->codecpar->block_align || !caf->frame_size) { - void *pkt_sizes; - unsigned alloc_size = caf->packets + 1; +#if SIZE_MAX - 10 < UINT_MAX + if (caf->pakt_buf_size > SIZE_MAX - 10) + return AVERROR(ERANGE); +#endif + uint8_t *pakt_buf = av_fast_realloc(caf->pakt_buf, &caf->pakt_buf_alloc_size, + caf->pakt_buf_size + (size_t)10); + if (!pakt_buf) + return AVERROR(ENOMEM); + caf->pakt_buf = pakt_buf; + pakt_buf += caf->pakt_buf_size; - if (!st->codecpar->block_align) { - if (UINT_MAX / sizeof(*caf->byte_size_buffer) < alloc_size) - return AVERROR(ERANGE); - - pkt_sizes = av_fast_realloc(caf->byte_size_buffer, - &caf->byte_size_buffer_sz, - alloc_size * sizeof(*caf->byte_size_buffer)); - if (!pkt_sizes) - return AVERROR(ENOMEM); - caf->byte_size_buffer = pkt_sizes; - caf->byte_size_buffer[caf->packets] = pkt->size; - } - if (!caf->frame_size) { - if (UINT_MAX / sizeof(*caf->frame_size_buffer) < alloc_size) - return AVERROR(ERANGE); - - pkt_sizes = av_fast_realloc(caf->frame_size_buffer, - &caf->frame_size_buffer_sz, - alloc_size * sizeof(*caf->frame_size_buffer)); - if (!pkt_sizes) - return AVERROR(ENOMEM); - caf->frame_size_buffer = pkt_sizes; - caf->frame_size_buffer[caf->packets] = pkt->duration; - } + if (!st->codecpar->block_align) + pakt_buf = put_variable_length_num(pakt_buf, pkt->size); + if (!caf->frame_size) + pakt_buf = put_variable_length_num(pakt_buf, pkt->duration); + caf->pakt_buf_size = pakt_buf - caf->pakt_buf; } caf->packets++; caf->total_duration += pkt->duration; @@ -294,47 +295,17 @@ static int caf_write_trailer(AVFormatContext *s) avio_wb64(pb, file_size - caf->data - 8); if (!par->block_align || !caf->frame_size || par->initial_padding || remainder_frames) { - int64_t size = 24; - valid_frames -= par->initial_padding; valid_frames -= remainder_frames; avio_seek(pb, file_size, SEEK_SET); ffio_wfourcc(pb, "pakt"); - avio_wb64(pb, 0); // size, to be replaced + avio_wb64(pb, 24 + caf->pakt_buf_size); // size avio_wb64(pb, packets); ///< mNumberPackets avio_wb64(pb, valid_frames); ///< mNumberValidFrames avio_wb32(pb, par->initial_padding); ///< mPrimingFrames avio_wb32(pb, remainder_frames); ///< mRemainderFrames - for (int i = 0; i < packets; i++) { - if (!par->block_align) { - for (int j = 4; j > 0; j--) { - unsigned top = caf->byte_size_buffer[i] >> j * 7; - if (top) { - avio_w8(pb, 128 | (uint8_t)top); - size++; - } - } - avio_w8(pb, caf->byte_size_buffer[i] & 127); - size++; - } - if (!caf->frame_size) { - for (int j = 4; j > 0; j--) { - unsigned top = caf->frame_size_buffer[i] >> j * 7; - if (top) { - avio_w8(pb, 128 | (uint8_t)top); - size++; - } - } - avio_w8(pb, caf->frame_size_buffer[i] & 127); - size++; - } - } - - int64_t end = avio_tell(pb); - avio_seek(pb, file_size + 4, SEEK_SET); - avio_wb64(pb, size); - avio_seek(pb, end, SEEK_SET); + avio_write(pb, caf->pakt_buf, caf->pakt_buf_size); } } @@ -345,8 +316,7 @@ static void caf_write_deinit(AVFormatContext *s) { CAFContext *caf = s->priv_data; - av_freep(&caf->byte_size_buffer); - av_freep(&caf->frame_size_buffer); + av_freep(&caf->pakt_buf); } const FFOutputFormat ff_caf_muxer = { -- 2.52.0 >From 2b82ab60fea0327a2fd606976fc677ae255902dc Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt <[email protected]> Date: Fri, 30 Jan 2026 15:02:33 +0100 Subject: [PATCH 2/2] avformat/cafenc: don't keep track of nb packets ourselves Just reuse AVStream.nb_frames. Signed-off-by: Andreas Rheinhardt <[email protected]> --- libavformat/cafenc.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/libavformat/cafenc.c b/libavformat/cafenc.c index 4542cc7b04..8879d13940 100644 --- a/libavformat/cafenc.c +++ b/libavformat/cafenc.c @@ -35,7 +35,6 @@ typedef struct { int64_t data; int64_t total_duration; - int64_t packets; uint32_t frame_size; uint8_t *pakt_buf; @@ -270,7 +269,6 @@ static int caf_write_packet(AVFormatContext *s, AVPacket *pkt) pakt_buf = put_variable_length_num(pakt_buf, pkt->duration); caf->pakt_buf_size = pakt_buf - caf->pakt_buf; } - caf->packets++; caf->total_duration += pkt->duration; avio_write(s->pb, pkt->data, pkt->size); @@ -286,8 +284,8 @@ static int caf_write_trailer(AVFormatContext *s) if (pb->seekable & AVIO_SEEKABLE_NORMAL) { int64_t file_size = avio_tell(pb); - int64_t packets = (!par->block_align || !caf->frame_size) ? caf->packets : 0; - int64_t valid_frames = caf->frame_size ? caf->packets * caf->frame_size : caf->total_duration; + int64_t packets = (!par->block_align || !caf->frame_size) ? st->nb_frames : 0; + int64_t valid_frames = caf->frame_size ? st->nb_frames * caf->frame_size : caf->total_duration; unsigned remainder_frames = valid_frames > caf->total_duration ? valid_frames - caf->total_duration : 0; -- 2.52.0 _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
