From 2c5362b499b106b10e7be985660701f2c3c6af79 Mon Sep 17 00:00:00 2001 From: Andre Noll Date: Sun, 1 Mar 2009 23:09:51 +0100 Subject: [PATCH] vss.c: Improve the fec timing code. This patch - Fixes a the bug where assert(start_buf) caused para_server to abort. - Gets rid of buffer underruns by introducing a quick hack that sends all but the first slice a bit early. - Moves some code from compute_next_fec_slice() to setup_next_fec_group() where it belongs. --- vss.c | 143 +++++++++++++++++++++++++++++++--------------------------- 1 file changed, 76 insertions(+), 67 deletions(-) diff --git a/vss.c b/vss.c index b8c7463b..dc598936 100644 --- a/vss.c +++ b/vss.c @@ -179,46 +179,77 @@ struct timeval *vss_chunk_time(void) return &mmd->afd.afhi.chunk_tv; } -static void setup_fec_group(struct fec_client *fc, struct vss_task *vsst) +/** + * Write a fec header to a buffer. + * + * \param buf The buffer to write to. + * \param h The fec header to write. + */ +static void write_fec_header(struct fec_client *fc) +{ + char *buf = (char *)fc->enc_buf; + + write_u32(buf, FEC_MAGIC); + + write_u8(buf + 4, fc->fcp->slices_per_group); + write_u8(buf + 5, fc->fcp->data_slices_per_group); + write_u32(buf + 6, (uint32_t)0); /* audio header len */ + + write_u32(buf + 10, fc->group.num); + write_u32(buf + 14, fc->group.bytes); + + write_u8(buf + 18, fc->slice.num); + write_u16(buf + 20, fc->slice.bytes); + memset(buf + 22, 0, 11); +} + +static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst) { - uint32_t num_bytes = 0, chunk_num, max_group_size, last_payload_size; + uint32_t max_group_size, last_payload_size; int i, k = fc->fcp->data_slices_per_group; - const char *start_buf = NULL; + size_t len; + const char *start_buf; struct timeval tmp, *chunk_tv = vss_chunk_time(); assert(chunk_tv); + if (fc->first_stream_chunk < 0) { + fc->stream_start = *now; + fc->first_stream_chunk = mmd->current_chunk; + fc->group.first_chunk = mmd->current_chunk; + fc->group.num = 0; + } else { + fc->group.first_chunk += fc->group.num_chunks; + fc->group.num++; + } + if (fc->group.first_chunk >= mmd->afd.afhi.chunks_total) + return 0; max_group_size = (fc->fcp->max_slice_bytes - FEC_HEADER_SIZE) * k; - chunk_num = fc->group.first_chunk; - for (;;) { + afh_get_chunk(fc->group.first_chunk, &mmd->afd.afhi, vsst->map, + &start_buf, &len); + for (i = fc->group.first_chunk, fc->group.bytes = 0; + i < mmd->afd.afhi.chunks_total; i++) { const char *buf; - size_t len; - if (chunk_num >= mmd->afd.afhi.chunks_total) + afh_get_chunk(i, &mmd->afd.afhi, vsst->map, &buf, &len); + if (fc->group.bytes + len > max_group_size) break; - afh_get_chunk(chunk_num, &mmd->afd.afhi, vsst->map, &buf, &len); - if (!start_buf) - start_buf = buf; - if (num_bytes + len > max_group_size) - break; - chunk_num++; - num_bytes += len; + fc->group.bytes += len; } - assert(start_buf); - fc->group.num_chunks = chunk_num - fc->group.first_chunk; - fc->group.num++; - fc->group.bytes = num_bytes; + fc->group.num_chunks = i - fc->group.first_chunk; fc->slice.num = 0; - fc->slice.bytes = ROUND_UP(num_bytes, k) / k; + fc->slice.bytes = ROUND_UP(fc->group.bytes, k) / k; /* The last slice will not be fully used */ - last_payload_size = num_bytes % fc->slice.bytes; + last_payload_size = fc->group.bytes % fc->slice.bytes; if (!last_payload_size) last_payload_size = fc->slice.bytes; - tv_scale(fc->group.num_chunks, chunk_tv, &fc->group.duration); tv_scale(fc->group.first_chunk - fc->first_stream_chunk, chunk_tv, &tmp); tv_add(&fc->stream_start, &tmp, &fc->group.start); + if (fc->group.num) /* quick hack to avoid buffer underruns */ + fc->group.start.tv_sec--; + tv_scale(fc->group.num_chunks, chunk_tv, &fc->group.duration); tv_divide(fc->fcp->slices_per_group, &fc->group.duration, &fc->group.slice_duration); @@ -228,39 +259,38 @@ static void setup_fec_group(struct fec_client *fc, struct vss_task *vsst) if (start_buf + k * fc->slice.bytes > vsst->map + mmd->size) { /* can not use last slice as it goes beyond the map */ - if (fc->extra_src_buf_size < fc->slice.bytes) + if (fc->extra_src_buf_size < fc->slice.bytes) { fc->extra_src_buf = para_realloc(fc->extra_src_buf, fc->slice.bytes); + fc->extra_src_buf_size = fc->slice.bytes; + } memcpy(fc->extra_src_buf, start_buf + (k - 1) * fc->slice.bytes, last_payload_size); memset(fc->extra_src_buf + last_payload_size, 0, fc->slice.bytes - last_payload_size); fc->src_data[k - 1] = fc->extra_src_buf; } - + if (fc->enc_buf_size < fc->slice.bytes + FEC_HEADER_SIZE) { + fc->enc_buf_size = fc->slice.bytes + FEC_HEADER_SIZE; + fc->enc_buf = para_realloc(fc->enc_buf, fc->enc_buf_size); + } + PARA_INFO_LOG("FEC group %d: %d chunks (%d - %d), duration: %lums\n", + fc->group.num, fc->group.num_chunks, fc->group.first_chunk, + fc->group.first_chunk + fc->group.num_chunks - 1, + tv2ms(&fc->group.duration)); + return 1; } -/** - * Write a fec header to a buffer. - * - * \param buf The buffer to write to. - * \param h The fec header to write. - */ -static void write_fec_header(struct fec_client *fc) +static int compute_next_fec_slice(struct fec_client *fc, struct vss_task *vsst) { - char *buf = (char *)fc->enc_buf; - - write_u32(buf, FEC_MAGIC); - - write_u8(buf + 4, fc->fcp->slices_per_group); - write_u8(buf + 5, fc->fcp->data_slices_per_group); - write_u32(buf + 6, (uint32_t)0); /* audio header len */ - - write_u32(buf + 10, fc->group.num); - write_u32(buf + 14, fc->group.bytes); - - write_u8(buf + 18, fc->slice.num); - write_u16(buf + 20, fc->slice.bytes); - memset(buf + 22, 0, 11); + if (fc->first_stream_chunk < 0 || fc->slice.num + == fc->fcp->slices_per_group) { + if (!setup_next_fec_group(fc, vsst)) + return 0; + } + write_fec_header(fc); + fec_encode(fc->parms, fc->src_data, fc->enc_buf + FEC_HEADER_SIZE, + fc->slice.num, fc->slice.bytes); + return 1; } /** @@ -283,28 +313,6 @@ size_t vss_get_fec_eof_packet(const char **buf) return FEC_HEADER_SIZE; } -static void compute_next_fec_slice(struct fec_client *fc, struct vss_task *vsst) -{ - if (fc->first_stream_chunk < 0) { - fc->stream_start = *now; - fc->first_stream_chunk = mmd->current_chunk; - fc->group.first_chunk = mmd->current_chunk; - fc->group.num = 0; - setup_fec_group(fc, vsst); - } else if (fc->slice.num == fc->fcp->slices_per_group) { - fc->group.first_chunk += fc->group.num_chunks; - setup_fec_group(fc, vsst); - - } - if (fc->enc_buf_size < fc->slice.bytes + FEC_HEADER_SIZE) { - fc->enc_buf_size = fc->slice.bytes + FEC_HEADER_SIZE; - fc->enc_buf = para_realloc(fc->enc_buf, fc->enc_buf_size); - } - write_fec_header(fc); - fec_encode(fc->parms, fc->src_data, fc->enc_buf + FEC_HEADER_SIZE, - fc->slice.num, fc->slice.bytes); -} - /** * Add one entry to the list of active fec clients. * @@ -761,7 +769,8 @@ static void vss_send(struct vss_task *vsst) list_for_each_entry_safe(fc, tmp_fc, &fec_client_list, node) { if (!next_slice_is_due(fc, NULL)) continue; - compute_next_fec_slice(fc, vsst); + if (!compute_next_fec_slice(fc, vsst)) + continue; PARA_DEBUG_LOG("sending %d:%d (%zu bytes)\n", fc->group.num, fc->slice.num, fc->slice.bytes); fc->fcp->send((char *)fc->enc_buf, -- 2.39.5