diff --git a/src/internal_modules/roc_core/parse_duration.cpp b/src/internal_modules/roc_core/parse_units.cpp
similarity index 56%
rename from src/internal_modules/roc_core/parse_duration.cpp
rename to src/internal_modules/roc_core/parse_units.cpp
index de7e33990..e16581a40 100644
--- a/src/internal_modules/roc_core/parse_duration.cpp
+++ b/src/internal_modules/roc_core/parse_units.cpp
@@ -6,7 +6,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-#include "roc_core/parse_duration.h"
+#include "roc_core/parse_units.h"
 #include "roc_core/log.h"
 #include "roc_core/stddefs.h"
 
@@ -84,5 +84,67 @@ bool parse_duration(const char* str, nanoseconds_t& result) {
     return true;
 }
 
+bool parse_size(const char* str, size_t& result) {
+    if (str == NULL) {
+        roc_log(LogError, "parse size: string is null");
+        return false;
+    }
+
+    const size_t kibibyte = 1024;
+    const size_t mebibyte = 1024 * kibibyte;
+    const size_t gibibyte = 1024 * mebibyte;
+
+    size_t multiplier = 1;
+
+    const size_t str_len = strlen(str);
+    const char* suffix;
+
+    // suffix is optional.
+    if ((suffix = find_suffix(str, str_len, "G"))) {
+        multiplier = gibibyte;
+    } else if ((suffix = find_suffix(str, str_len, "M"))) {
+        multiplier = mebibyte;
+    } else if ((suffix = find_suffix(str, str_len, "K"))) {
+        multiplier = kibibyte;
+    }
+
+    if (!isdigit(*str)) {
+        roc_log(LogError,
+                "parse size: invalid format, not a number, expected <number>[<suffix>], "
+                "where suffix=<K|M|G>");
+        return false;
+    }
+
+    char* number_end = NULL;
+    unsigned long long number = strtoull(str, &number_end, 10);
+
+    if (number == ULLONG_MAX || (!suffix && *number_end != '\0')
+        || (suffix && number_end != suffix)) {
+        roc_log(LogError,
+                "parse size: invalid format, can't parse number, expected "
+                "<number>[<suffix>], where suffix=<K|M|G>");
+        return false;
+    }
+
+    size_t number_converted = number;
+    if (number_converted < number) {
+        roc_log(LogError,
+                "parse size: too large, can't parse number, expected "
+                "<number>[<suffix>], where suffix=<K|M|G>");
+        return false;
+    }
+
+    size_t output = number_converted * multiplier;
+    if (output / multiplier != number_converted) {
+        roc_log(LogError,
+                "parse size: too large, can't parse number, expected "
+                "<number>[<suffix>], where suffix=<K|M|G>");
+        return false;
+    }
+
+    result = output;
+    return true;
+}
+
 } // namespace core
 } // namespace roc
diff --git a/src/internal_modules/roc_core/parse_duration.h b/src/internal_modules/roc_core/parse_units.h
similarity index 60%
rename from src/internal_modules/roc_core/parse_duration.h
rename to src/internal_modules/roc_core/parse_units.h
index 71b1488aa..9e7052e0d 100644
--- a/src/internal_modules/roc_core/parse_duration.h
+++ b/src/internal_modules/roc_core/parse_units.h
@@ -6,11 +6,11 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-//! @file roc_core/parse_duration.h
-//! @brief Parse duration.
+//! @file roc_core/parse_units.h
+//! @brief Parse units like duration, size, etc.
 
-#ifndef ROC_CORE_PARSE_DURATION_H_
-#define ROC_CORE_PARSE_DURATION_H_
+#ifndef ROC_CORE_PARSE_UNITS_H_
+#define ROC_CORE_PARSE_UNITS_H_
 
 #include "roc_core/attributes.h"
 #include "roc_core/time.h"
@@ -33,7 +33,20 @@ namespace core {
 //!  false if string can't be parsed.
 ROC_ATTR_NODISCARD bool parse_duration(const char* string, nanoseconds_t& result);
 
+//! Parse size from string.
+//!
+//! @remarks
+//!  The input string should be in one of the following forms:
+//!   - "<number>"
+//!   - "<number>K"
+//!   - "<number>M"
+//!   - "<number>G"
+//!
+//! @returns
+//!  false if string can't be parsed.
+ROC_ATTR_NODISCARD bool parse_size(const char* string, size_t& result);
+
 } // namespace core
 } // namespace roc
 
-#endif // ROC_CORE_PARSE_DURATION_H_
+#endif // ROC_CORE_PARSE_UNITS_H_
diff --git a/src/tests/roc_core/test_parse_duration.cpp b/src/tests/roc_core/test_parse_duration.cpp
deleted file mode 100644
index 0fe85320f..000000000
--- a/src/tests/roc_core/test_parse_duration.cpp
+++ /dev/null
@@ -1,57 +0,0 @@
-/*
- * Copyright (c) 2015 Roc Streaming authors
- *
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/.
- */
-
-#include <CppUTest/TestHarness.h>
-
-#include "roc_core/parse_duration.h"
-#include "roc_core/time.h"
-
-namespace roc {
-namespace core {
-
-TEST_GROUP(parse_duration) {};
-
-TEST(parse_duration, error) {
-    nanoseconds_t result = 0;
-
-    CHECK(!parse_duration(NULL, result));
-    CHECK(!parse_duration("", result));
-    CHECK(!parse_duration("1", result));
-    CHECK(!parse_duration("s", result));
-    CHECK(!parse_duration("1 s", result));
-    CHECK(!parse_duration(" 1s", result));
-    CHECK(!parse_duration("1s ", result));
-    CHECK(!parse_duration("!s", result));
-    CHECK(!parse_duration("s1", result));
-    CHECK(!parse_duration("1x", result));
-}
-
-TEST(parse_duration, parse) {
-    nanoseconds_t result = 0;
-
-    CHECK(parse_duration("123ns", result));
-    CHECK(result == 123 * Nanosecond);
-
-    CHECK(parse_duration("123us", result));
-    CHECK(result == 123 * Microsecond);
-
-    CHECK(parse_duration("123ms", result));
-    CHECK(result == 123 * Millisecond);
-
-    CHECK(parse_duration("123s", result));
-    CHECK(result == 123 * Second);
-
-    CHECK(parse_duration("123m", result));
-    CHECK(result == 123 * Minute);
-
-    CHECK(parse_duration("123h", result));
-    CHECK(result == 123 * Hour);
-}
-
-} // namespace core
-} // namespace roc
diff --git a/src/tests/roc_core/test_parse_units.cpp b/src/tests/roc_core/test_parse_units.cpp
new file mode 100644
index 000000000..42bdc871e
--- /dev/null
+++ b/src/tests/roc_core/test_parse_units.cpp
@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2015 Roc Streaming authors
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <CppUTest/TestHarness.h>
+
+#include "roc_core/parse_units.h"
+#include "roc_core/time.h"
+
+namespace roc {
+namespace core {
+
+TEST_GROUP(parse_units) {};
+
+TEST(parse_units, parse_duration_error) {
+    nanoseconds_t result = 0;
+
+    CHECK(!parse_duration(NULL, result));
+    CHECK(!parse_duration("", result));
+    CHECK(!parse_duration("1", result));
+    CHECK(!parse_duration("s", result));
+    CHECK(!parse_duration("1 s", result));
+    CHECK(!parse_duration(" 1s", result));
+    CHECK(!parse_duration("1s ", result));
+    CHECK(!parse_duration("!s", result));
+    CHECK(!parse_duration("s1", result));
+    CHECK(!parse_duration("1x", result));
+}
+
+TEST(parse_units, parse_duration) {
+    nanoseconds_t result = 0;
+
+    CHECK(parse_duration("123ns", result));
+    CHECK(result == 123 * Nanosecond);
+
+    CHECK(parse_duration("123us", result));
+    CHECK(result == 123 * Microsecond);
+
+    CHECK(parse_duration("123ms", result));
+    CHECK(result == 123 * Millisecond);
+
+    CHECK(parse_duration("123s", result));
+    CHECK(result == 123 * Second);
+
+    CHECK(parse_duration("123m", result));
+    CHECK(result == 123 * Minute);
+
+    CHECK(parse_duration("123h", result));
+    CHECK(result == 123 * Hour);
+}
+
+TEST(parse_units, parse_size_error) {
+    size_t result = 0;
+
+    CHECK(!parse_size(NULL, result));
+    CHECK(!parse_size("", result));
+    CHECK(!parse_size("K", result));
+    CHECK(!parse_size("1 K", result));
+    CHECK(!parse_size(" 1K", result));
+    CHECK(!parse_size("1K ", result));
+    CHECK(!parse_size("!K", result));
+    CHECK(!parse_size("K1", result));
+    CHECK(!parse_size("1x", result));
+}
+
+TEST(parse_units, parse_size) {
+    size_t result = 0;
+
+    const size_t kibibyte = 1024;
+    const size_t mebibyte = 1024 * kibibyte;
+    const size_t gibibyte = 1024 * mebibyte;
+
+    CHECK(parse_size("123", result));
+    CHECK(result == 123);
+
+    CHECK(parse_size("123K", result));
+    CHECK(result == 123 * kibibyte);
+
+    CHECK(parse_size("123M", result));
+    CHECK(result == 123 * mebibyte);
+
+    CHECK(parse_size("1G", result));
+    CHECK(result == 1 * gibibyte);
+}
+
+TEST(parse_units, parse_size_overflows_due_to_sizeof_size_t) {
+    if (SIZE_MAX < ULLONG_MAX) {
+        char s[32];
+        snprintf(s, 32, "%llu", ULLONG_MAX - 1);
+        size_t result = 0;
+        CHECK_FALSE(parse_size(s, result));
+    }
+}
+
+TEST(parse_units, parse_size_overflows_due_to_multiplier) {
+    char s[32];
+    snprintf(s, 32, "%zuK", SIZE_MAX - 1);
+    size_t result = 0;
+    CHECK_FALSE(parse_size(s, result));
+}
+
+} // namespace core
+} // namespace roc
diff --git a/src/tools/roc_copy/main.cpp b/src/tools/roc_copy/main.cpp
index 01e18e952..d97b9bfc2 100644
--- a/src/tools/roc_copy/main.cpp
+++ b/src/tools/roc_copy/main.cpp
@@ -11,7 +11,7 @@
 #include "roc_core/crash_handler.h"
 #include "roc_core/heap_arena.h"
 #include "roc_core/log.h"
-#include "roc_core/parse_duration.h"
+#include "roc_core/parse_units.h"
 #include "roc_core/scoped_ptr.h"
 #include "roc_pipeline/transcoder_sink.h"
 #include "roc_sndio/backend_dispatcher.h"
diff --git a/src/tools/roc_recv/cmdline.ggo b/src/tools/roc_recv/cmdline.ggo
index 684db2eb4..851965074 100644
--- a/src/tools/roc_recv/cmdline.ggo
+++ b/src/tools/roc_recv/cmdline.ggo
@@ -44,14 +44,14 @@ section "Options"
     option "choppy-play-timeout" - "Choppy playback timeout, TIME units"
         string optional
 
-    option "packet-limit" - "Maximum packet size, in bytes"
-        int optional
+    option "frame-len" - "Duration of the internal frames, TIME units"
+        typestr="TIME" string optional
 
-    option "frame-limit" - "Maximum internal frame size, in bytes"
-        int optional
+    option "max-packet-size" - "Maximum packet size, in SIZE units"
+        typestr="SIZE" string optional
 
-    option "frame-length" - "Duration of the internal frames, TIME units"
-        typestr="TIME" string optional
+    option "max-frame-size" - "Maximum internal frame size, in SIZE units"
+        typestr="SIZE" string optional
 
     option "rate" - "Override output sample rate, Hz"
         int optional
@@ -92,6 +92,9 @@ FILE_FORMAT is the output file format name, e.g.:
 TIME is an integer number with a suffix, e.g.:
   123ns; 123us; 123ms; 123s; 123m; 123h;
 
+SIZE is an integer number with an optional suffix, e.g.:
+  123; 123K; 123M; 123G;
+
 Use --list-supported option to print the list of the supported
 URI schemes and file formats.
 
diff --git a/src/tools/roc_recv/main.cpp b/src/tools/roc_recv/main.cpp
index 628649aed..3714111b9 100644
--- a/src/tools/roc_recv/main.cpp
+++ b/src/tools/roc_recv/main.cpp
@@ -16,7 +16,7 @@
 #include "roc_core/crash_handler.h"
 #include "roc_core/heap_arena.h"
 #include "roc_core/log.h"
-#include "roc_core/parse_duration.h"
+#include "roc_core/parse_units.h"
 #include "roc_core/scoped_ptr.h"
 #include "roc_netio/network_loop.h"
 #include "roc_node/context.h"
@@ -64,65 +64,40 @@ int main(int argc, char** argv) {
         break;
     }
 
-    node::ContextConfig context_config;
-
-    if (args.packet_limit_given) {
-        if (args.packet_limit_arg <= 0) {
-            roc_log(LogError, "invalid --packet-limit: should be > 0");
-            return 1;
-        }
-        context_config.max_packet_size = (size_t)args.packet_limit_arg;
-    }
-
-    if (args.frame_limit_given) {
-        if (args.frame_limit_arg <= 0) {
-            roc_log(LogError, "invalid --frame-limit: should be > 0");
-            return 1;
-        }
-        context_config.max_frame_size = (size_t)args.frame_limit_arg;
-    }
-
-    core::HeapArena heap_arena;
-
-    node::Context context(context_config, heap_arena);
-    if (!context.is_valid()) {
-        roc_log(LogError, "can't initialize node context");
-        return 1;
-    }
-
-    sndio::BackendDispatcher backend_dispatcher(context.arena());
-
-    if (args.list_supported_given) {
-        if (!address::print_supported(context.arena())) {
-            return 1;
-        }
-
-        if (!sndio::print_supported(backend_dispatcher, context.arena())) {
-            return 1;
-        }
-
-        return 0;
-    }
-
     pipeline::ReceiverConfig receiver_config;
 
     sndio::Config io_config;
     io_config.sample_spec.set_channel_set(
         receiver_config.common.output_sample_spec.channel_set());
 
-    if (args.frame_length_given) {
-        if (!core::parse_duration(args.frame_length_arg, io_config.frame_length)) {
-            roc_log(LogError, "invalid --frame-length: bad format");
+    if (args.frame_len_given) {
+        if (!core::parse_duration(args.frame_len_arg, io_config.frame_length)) {
+            roc_log(LogError, "invalid --frame-len: bad format");
             return 1;
         }
         if (receiver_config.common.output_sample_spec.ns_2_samples_overall(
                 io_config.frame_length)
             <= 0) {
-            roc_log(LogError, "invalid --frame-length: should be > 0");
+            roc_log(LogError, "invalid --frame-len: should be > 0");
             return 1;
         }
     }
 
+    if (args.io_latency_given) {
+        if (!core::parse_duration(args.io_latency_arg, io_config.latency)) {
+            roc_log(LogError, "invalid --io-latency");
+            return 1;
+        }
+    }
+
+    if (args.rate_given) {
+        if (args.rate_arg <= 0) {
+            roc_log(LogError, "invalid --rate: should be > 0");
+            return 1;
+        }
+        io_config.sample_spec.set_sample_rate((size_t)args.rate_arg);
+    }
+
     sndio::BackendMap::instance().set_frame_size(
         io_config.frame_length, receiver_config.common.output_sample_spec);
 
@@ -235,19 +210,62 @@ int main(int argc, char** argv) {
     receiver_config.common.enable_profiling = args.profiling_flag;
     receiver_config.common.enable_beeping = args.beep_flag;
 
-    if (args.io_latency_given) {
-        if (!core::parse_duration(args.io_latency_arg, io_config.latency)) {
-            roc_log(LogError, "invalid --io-latency");
+    node::ContextConfig context_config;
+
+    if (args.max_packet_size_given) {
+        if (!core::parse_size(args.max_packet_size_arg, context_config.max_packet_size)) {
+            roc_log(LogError, "invalid --max-packet-size");
+            return 1;
+        }
+        if (context_config.max_packet_size == 0) {
+            roc_log(LogError, "invalid --max-packet-size: should be > 0");
             return 1;
         }
     }
 
-    if (args.rate_given) {
-        if (args.rate_arg <= 0) {
-            roc_log(LogError, "invalid --rate: should be > 0");
+    if (args.max_frame_size_given) {
+        if (!core::parse_size(args.max_frame_size_arg, context_config.max_frame_size)) {
+            roc_log(LogError, "invalid --max-frame-size");
             return 1;
         }
-        io_config.sample_spec.set_sample_rate((size_t)args.rate_arg);
+        if (context_config.max_frame_size == 0) {
+            roc_log(LogError, "invalid --max-frame-size: should be > 0");
+            return 1;
+        }
+    } else {
+        audio::SampleSpec spec = io_config.sample_spec;
+        if (spec.sample_rate() == 0) {
+            spec.set_sample_rate(48000);
+        }
+        if (spec.num_channels() == 0) {
+            spec.set_channel_set(audio::ChannelSet(audio::ChanLayout_Surround,
+                                                   audio::ChanOrder_Smpte,
+                                                   audio::ChanMask_Surround_7_1_4));
+        }
+        context_config.max_frame_size =
+            spec.ns_2_samples_overall(io_config.frame_length) * sizeof(audio::sample_t);
+    }
+
+    core::HeapArena heap_arena;
+
+    node::Context context(context_config, heap_arena);
+    if (!context.is_valid()) {
+        roc_log(LogError, "can't initialize node context");
+        return 1;
+    }
+
+    sndio::BackendDispatcher backend_dispatcher(context.arena());
+
+    if (args.list_supported_given) {
+        if (!address::print_supported(context.arena())) {
+            return 1;
+        }
+
+        if (!sndio::print_supported(backend_dispatcher, context.arena())) {
+            return 1;
+        }
+
+        return 0;
     }
 
     address::IoUri output_uri(context.arena());
diff --git a/src/tools/roc_send/cmdline.ggo b/src/tools/roc_send/cmdline.ggo
index bcbb3e31b..cf5487a58 100644
--- a/src/tools/roc_send/cmdline.ggo
+++ b/src/tools/roc_send/cmdline.ggo
@@ -29,17 +29,17 @@ section "Options"
     option "nbrpr" - "Number of repair packets in FEC block"
         int optional
 
-    option "packet-length" - "Outgoing packet length, TIME units"
+    option "packet-len" - "Outgoing packet length, TIME units"
         string optional
 
-    option "packet-limit" - "Maximum packet size, in bytes"
-        int optional
+    option "frame-len" - "Duration of the internal frames, TIME units"
+        typestr="TIME" string optional
 
-    option "frame-limit" - "Maximum internal frame size, in bytes"
-        int optional
+    option "max-packet-size" - "Maximum packet size, in SIZE units"
+        typestr="SIZE" string optional
 
-    option "frame-length" - "Duration of the internal frames, TIME units"
-        typestr="TIME" string optional
+    option "max-frame-size" - "Maximum internal frame size, in SIZE units"
+        typestr="SIZE" string optional
 
     option "rate" - "Override input sample rate, Hz"
         int optional
@@ -71,6 +71,9 @@ FILE_FORMAT is the output file format name, e.g.:
 TIME is an integer number with a suffix, e.g.:
   123ns; 123us; 123ms; 123s; 123m; 123h;
 
+SIZE is an integer number with an optional suffix, e.g.:
+  123; 123K; 123M; 123G;
+
 Use --list-supported option to print the list of the supported
 URI schemes and file formats.
 
diff --git a/src/tools/roc_send/main.cpp b/src/tools/roc_send/main.cpp
index 0a7f3e195..bffb2ede6 100644
--- a/src/tools/roc_send/main.cpp
+++ b/src/tools/roc_send/main.cpp
@@ -15,7 +15,7 @@
 #include "roc_core/crash_handler.h"
 #include "roc_core/heap_arena.h"
 #include "roc_core/log.h"
-#include "roc_core/parse_duration.h"
+#include "roc_core/parse_units.h"
 #include "roc_core/scoped_ptr.h"
 #include "roc_netio/network_loop.h"
 #include "roc_netio/udp_sender_port.h"
@@ -63,22 +63,60 @@ int main(int argc, char** argv) {
         break;
     }
 
+    pipeline::SenderConfig sender_config;
+
+    sndio::Config io_config;
+    io_config.sample_spec.set_channel_set(sender_config.input_sample_spec.channel_set());
+
+    if (args.packet_len_given) {
+        if (!core::parse_duration(args.packet_len_arg, sender_config.packet_length)) {
+            roc_log(LogError, "invalid --packet-len");
+            return 1;
+        }
+    }
+
+    if (args.frame_len_given) {
+        if (!core::parse_duration(args.frame_len_arg, io_config.frame_length)) {
+            roc_log(LogError, "invalid --frame-len: bad format");
+            return 1;
+        }
+        if (sender_config.input_sample_spec.ns_2_samples_overall(io_config.frame_length)
+            <= 0) {
+            roc_log(LogError, "invalid --frame-len: should be > 0");
+            return 1;
+        }
+    }
+
     node::ContextConfig context_config;
 
-    if (args.packet_limit_given) {
-        if (args.packet_limit_arg <= 0) {
-            roc_log(LogError, "invalid --packet-limit: should be > 0");
+    if (args.max_packet_size_given) {
+        if (!core::parse_size(args.max_packet_size_arg, context_config.max_packet_size)) {
+            roc_log(LogError, "invalid --max-packet-size");
             return 1;
         }
-        context_config.max_packet_size = (size_t)args.packet_limit_arg;
+        if (context_config.max_packet_size == 0) {
+            roc_log(LogError, "invalid --max-packet-size: should be > 0");
+            return 1;
+        }
+    } else {
+        size_t extra_space = 64;
+        // TODO(gh-608): take size from --packet-encoding instead of assuming 2 bytes per
+        // sample
+        context_config.max_packet_size = 2
+                * sender_config.input_sample_spec.ns_2_samples_overall(
+                    sender_config.packet_length)
+            + extra_space;
     }
 
-    if (args.frame_limit_given) {
-        if (args.frame_limit_arg <= 0) {
-            roc_log(LogError, "invalid --frame-limit: should be > 0");
+    if (args.max_frame_size_given) {
+        if (!core::parse_size(args.max_frame_size_arg, context_config.max_frame_size)) {
+            roc_log(LogError, "invalid --max-frame-size");
+            return 1;
+        }
+        if (context_config.max_frame_size == 0) {
+            roc_log(LogError, "invalid --max-frame-size: should be > 0");
             return 1;
         }
-        context_config.max_frame_size = (size_t)args.frame_limit_arg;
     }
 
     core::HeapArena heap_arena;
@@ -102,30 +140,6 @@ int main(int argc, char** argv) {
         return 0;
     }
 
-    pipeline::SenderConfig sender_config;
-
-    sndio::Config io_config;
-    io_config.sample_spec.set_channel_set(sender_config.input_sample_spec.channel_set());
-
-    if (args.packet_length_given) {
-        if (!core::parse_duration(args.packet_length_arg, sender_config.packet_length)) {
-            roc_log(LogError, "invalid --packet-length");
-            return 1;
-        }
-    }
-
-    if (args.frame_length_given) {
-        if (!core::parse_duration(args.frame_length_arg, io_config.frame_length)) {
-            roc_log(LogError, "invalid --frame-length: bad format");
-            return 1;
-        }
-        if (sender_config.input_sample_spec.ns_2_samples_overall(io_config.frame_length)
-            <= 0) {
-            roc_log(LogError, "invalid --frame-length: should be > 0");
-            return 1;
-        }
-    }
-
     sndio::BackendMap::instance().set_frame_size(io_config.frame_length,
                                                  sender_config.input_sample_spec);