| /* |
| * AMV muxer |
| * |
| * Copyright (C) 2020 Zane van Iperen (zane@zanevaniperen.com) |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| #include "avformat.h" |
| #include "riff.h" |
| #include "internal.h" |
| #include "avio_internal.h" |
| #include "libavutil/intreadwrite.h" |
| #include "libavutil/avassert.h" |
| |
| /* |
| * Things to note: |
| * - AMV is a hard-coded (and broken) subset of AVI. It's not worth sullying the |
| * existing AVI muxer with its filth. |
| * - No separate demuxer as the existing AVI demuxer can handle these. |
| * - The sizes of certain tags are deliberately set to 0 as some players break |
| * when they're set correctly. Ditto with some header fields. |
| * - There is no index. |
| * - Players are **very** sensitive to the frame order and sizes. |
| * - Frames must be strictly interleaved as V-A, any V-V or A-A will |
| * cause crashes. |
| * - Variable video frame sizes seem to be handled fine. |
| * - Variable audio frame sizes cause crashes. |
| * - If audio is shorter than video, it's padded with silence. |
| * - If video is shorter than audio, the most recent frame is repeated. |
| */ |
| |
| #define AMV_STREAM_COUNT 2 |
| #define AMV_STREAM_VIDEO 0 |
| #define AMV_STREAM_AUDIO 1 |
| #define AMV_VIDEO_STRH_SIZE 56 |
| #define AMV_VIDEO_STRF_SIZE 36 |
| #define AMV_AUDIO_STRH_SIZE 48 |
| #define AMV_AUDIO_STRF_SIZE 20 /* sizeof(WAVEFORMATEX) + 2 */ |
| |
| typedef struct AMVContext |
| { |
| int64_t riff_start; |
| int64_t movi_list; |
| int64_t offset_duration; |
| int last_stream; |
| |
| int32_t us_per_frame; /* Microseconds per frame. */ |
| |
| int32_t aframe_size; /* Expected audio frame size. */ |
| int32_t ablock_align; /* Expected audio block align. */ |
| AVPacket apad; /* Dummy audio packet for padding. */ |
| AVPacket vpad; /* Most recent video frame, for padding. */ |
| |
| /* |
| * Cumulative PTS values for each stream, used for the final |
| * duration calculcation. |
| */ |
| int64_t lastpts[AMV_STREAM_COUNT]; |
| } AMVContext; |
| |
| /* ff_{start,end}_tag(), but sets the size to 0. */ |
| static int64_t amv_start_tag(AVIOContext *pb, const char *tag) |
| { |
| ffio_wfourcc(pb, tag); |
| avio_wl32(pb, 0); |
| return avio_tell(pb); |
| } |
| |
| static void amv_end_tag(AVIOContext *pb, int64_t start) |
| { |
| int64_t pos; |
| av_assert0((start&1) == 0); |
| |
| pos = avio_tell(pb); |
| if (pos & 1) |
| avio_w8(pb, 0); |
| } |
| |
| static av_cold int amv_init(AVFormatContext *s) |
| { |
| AMVContext *amv = s->priv_data; |
| AVStream *vst, *ast; |
| int ret; |
| |
| amv->last_stream = -1; |
| |
| if (s->nb_streams != AMV_STREAM_COUNT) { |
| av_log(s, AV_LOG_ERROR, "AMV files only support 2 streams\n"); |
| return AVERROR(EINVAL); |
| } |
| |
| vst = s->streams[AMV_STREAM_VIDEO]; |
| ast = s->streams[AMV_STREAM_AUDIO]; |
| |
| if (vst->codecpar->codec_id != AV_CODEC_ID_AMV) { |
| av_log(s, AV_LOG_ERROR, "First AMV stream must be %s\n", |
| avcodec_get_name(AV_CODEC_ID_AMV)); |
| return AVERROR(EINVAL); |
| } |
| |
| if (ast->codecpar->codec_id != AV_CODEC_ID_ADPCM_IMA_AMV) { |
| av_log(s, AV_LOG_ERROR, "Second AMV stream must be %s\n", |
| avcodec_get_name(AV_CODEC_ID_ADPCM_IMA_AMV)); |
| return AVERROR(EINVAL); |
| } |
| |
| /* These files are broken-enough as they are. They shouldn't be streamed. */ |
| if (!(s->pb->seekable & AVIO_SEEKABLE_NORMAL)) { |
| av_log(s, AV_LOG_ERROR, "Stream not seekable, unable to write output file\n"); |
| return AVERROR(EINVAL); |
| } |
| |
| amv->us_per_frame = av_rescale(AV_TIME_BASE, vst->time_base.num, vst->time_base.den); |
| amv->aframe_size = av_rescale(ast->codecpar->sample_rate, amv->us_per_frame, AV_TIME_BASE); |
| amv->ablock_align = 8 + (FFALIGN(amv->aframe_size, 2) / 2); |
| |
| av_log(s, AV_LOG_TRACE, "us_per_frame = %d\n", amv->us_per_frame); |
| av_log(s, AV_LOG_TRACE, "aframe_size = %d\n", amv->aframe_size); |
| av_log(s, AV_LOG_TRACE, "ablock_align = %d\n", amv->ablock_align); |
| |
| /* |
| * Bail if the framerate's too high. Prevents the audio frame size from |
| * getting too small. 63fps is the closest value to 60fps that divides |
| * cleanly, so cap it there. |
| */ |
| if (amv->us_per_frame < 15873) { |
| av_log(s, AV_LOG_ERROR, "Refusing to mux >63fps video\n"); |
| return AVERROR(EINVAL); |
| } |
| |
| /* |
| * frame_size will be set if coming from the encoder. |
| * Make sure the its been configured correctly. The audio frame duration |
| * needs to match that of the video. |
| */ |
| if (ast->codecpar->frame_size) { |
| AVCodecParameters *par = ast->codecpar; |
| int bad = 0; |
| |
| if (par->frame_size != amv->aframe_size) { |
| av_log(s, AV_LOG_ERROR, "Invalid audio frame size. Got %d, wanted %d\n", |
| par->frame_size, amv->aframe_size); |
| bad = 1; |
| } |
| |
| if (par->block_align != amv->ablock_align) { |
| av_log(s, AV_LOG_ERROR, "Invalid audio block align. Got %d, wanted %d\n", |
| par->block_align, amv->ablock_align); |
| bad = 1; |
| } |
| |
| if (bad) { |
| av_log(s, AV_LOG_ERROR, "Try -block_size %d\n", amv->aframe_size); |
| return AVERROR(EINVAL); |
| } |
| |
| if (ast->codecpar->sample_rate % amv->aframe_size) { |
| av_log(s, AV_LOG_ERROR, "Audio sample rate not a multiple of the frame size.\n" |
| "Please change video frame rate. Suggested rates: 10,14,15,18,21,25,30\n"); |
| return AVERROR(EINVAL); |
| } |
| } else { |
| /* If remuxing from the same source, then this will match the video. */ |
| int32_t aus = av_rescale(AV_TIME_BASE, ast->time_base.num, ast->time_base.den); |
| if (aus != amv->us_per_frame) { |
| av_log(s, AV_LOG_ERROR, "Cannot remux streams with a different time base\n"); |
| return AVERROR(EINVAL); |
| } |
| } |
| |
| /* Allocate and fill dummy packet so we can pad the audio. */ |
| if ((ret = av_new_packet(&amv->apad, amv->ablock_align)) < 0) |
| return ret; |
| |
| amv->apad.stream_index = AMV_STREAM_AUDIO; |
| memset(amv->apad.data, 0, amv->ablock_align); |
| AV_WL32(amv->apad.data + 4, amv->aframe_size); |
| |
| av_init_packet(&amv->vpad); |
| amv->vpad.stream_index = AMV_STREAM_VIDEO; |
| amv->vpad.duration = 1; |
| return 0; |
| } |
| |
| static void amv_deinit(AVFormatContext *s) |
| { |
| AMVContext *amv = s->priv_data; |
| |
| av_packet_unref(&amv->apad); |
| av_packet_unref(&amv->vpad); |
| } |
| |
| static void amv_write_vlist(AVFormatContext *s, AVCodecParameters *par) |
| { |
| int64_t tag_list, tag_str; |
| |
| av_assert0(par->codec_id == AV_CODEC_ID_AMV); |
| |
| tag_list = amv_start_tag(s->pb, "LIST"); |
| ffio_wfourcc(s->pb, "strl"); |
| tag_str = ff_start_tag(s->pb, "strh"); |
| ffio_fill(s->pb, 0, AMV_VIDEO_STRH_SIZE); |
| ff_end_tag(s->pb, tag_str); |
| |
| tag_str = ff_start_tag(s->pb, "strf"); |
| ffio_fill(s->pb, 0, AMV_VIDEO_STRF_SIZE); |
| ff_end_tag(s->pb, tag_str); |
| |
| amv_end_tag(s->pb, tag_list); |
| } |
| |
| static void amv_write_alist(AVFormatContext *s, AVCodecParameters *par) |
| { |
| uint8_t buf[AMV_AUDIO_STRF_SIZE]; |
| AVIOContext *pb = s->pb; |
| int64_t tag_list, tag_str; |
| |
| av_assert0(par->codec_id == AV_CODEC_ID_ADPCM_IMA_AMV); |
| |
| tag_list = amv_start_tag(pb, "LIST"); |
| ffio_wfourcc(pb, "strl"); |
| tag_str = ff_start_tag(pb, "strh"); |
| ffio_fill(s->pb, 0, AMV_AUDIO_STRH_SIZE); |
| ff_end_tag(pb, tag_str); |
| |
| /* Bodge an (incorrect) WAVEFORMATEX (+2 pad bytes) */ |
| tag_str = ff_start_tag(pb, "strf"); |
| AV_WL16(buf + 0, 1); |
| AV_WL16(buf + 2, par->channels); |
| AV_WL32(buf + 4, par->sample_rate); |
| AV_WL32(buf + 8, par->sample_rate * par->channels * 2); |
| AV_WL16(buf + 12, 2); |
| AV_WL16(buf + 14, 16); |
| AV_WL16(buf + 16, 0); |
| AV_WL16(buf + 18, 0); |
| avio_write(pb, buf, AMV_AUDIO_STRF_SIZE); |
| ff_end_tag(pb, tag_str); |
| |
| amv_end_tag(pb, tag_list); |
| } |
| |
| static int amv_write_header(AVFormatContext *s) |
| { |
| AMVContext *amv = s->priv_data; |
| AVIOContext *pb = s->pb; |
| AVStream *vst = s->streams[AMV_STREAM_VIDEO]; |
| AVStream *ast = s->streams[AMV_STREAM_AUDIO]; |
| uint8_t amvh[56] = {0}; |
| int64_t list1; |
| |
| amv->riff_start = amv_start_tag(pb, "RIFF"); |
| ffio_wfourcc(pb, "AMV "); |
| list1 = amv_start_tag(pb, "LIST"); |
| ffio_wfourcc(pb, "hdrl"); |
| |
| ffio_wfourcc(pb, "amvh"); |
| avio_wl32(pb, 56); |
| |
| AV_WL32(amvh + 0, amv->us_per_frame); |
| AV_WL32(amvh + 32, vst->codecpar->width); |
| AV_WL32(amvh + 36, vst->codecpar->height); |
| AV_WL32(amvh + 40, vst->time_base.den); |
| AV_WL32(amvh + 44, vst->time_base.num); |
| AV_WL32(amvh + 48, 0); |
| AV_WL32(amvh + 52, 0); /* duration, filled in later. */ |
| |
| avio_write(pb, amvh, sizeof(amvh)); |
| amv->offset_duration = avio_tell(pb) - 4; |
| |
| amv_write_vlist(s, vst->codecpar); |
| amv_write_alist(s, ast->codecpar); |
| amv_end_tag(pb, list1); |
| |
| amv->movi_list = amv_start_tag(pb, "LIST"); |
| ffio_wfourcc(pb, "movi"); |
| return 0; |
| } |
| |
| static int amv_write_packet_internal(AVFormatContext *s, AVPacket *pkt) |
| { |
| AMVContext *amv = s->priv_data; |
| |
| if (pkt->stream_index == AMV_STREAM_VIDEO) |
| ffio_wfourcc(s->pb, "00dc"); |
| else if (pkt->stream_index == AMV_STREAM_AUDIO) |
| ffio_wfourcc(s->pb, "01wb"); |
| else |
| av_assert0(0); |
| |
| if (pkt->stream_index == AMV_STREAM_AUDIO && pkt->size != amv->ablock_align) { |
| /* Can happen when remuxing files produced by another encoder. */ |
| av_log(s, AV_LOG_WARNING, "Invalid audio packet size (%d != %d)\n", |
| pkt->size, amv->ablock_align); |
| } |
| |
| avio_wl32(s->pb, pkt->size); |
| avio_write(s->pb, pkt->data, pkt->size); |
| |
| amv->lastpts[pkt->stream_index] += pkt->duration; |
| amv->last_stream = pkt->stream_index; |
| return 0; |
| } |
| |
| static int amv_pad(AVFormatContext *s, AVPacket *pkt) |
| { |
| AMVContext *amv = s->priv_data; |
| int stream_index = pkt->stream_index; |
| |
| if (stream_index != amv->last_stream) |
| return 0; |
| |
| stream_index = (stream_index + 1) % s->nb_streams; |
| if (stream_index == AMV_STREAM_VIDEO) |
| return amv_write_packet_internal(s, &amv->vpad); |
| else if (stream_index == AMV_STREAM_AUDIO) |
| return amv_write_packet_internal(s, &amv->apad); |
| else |
| av_assert0(0); |
| |
| return AVERROR(EINVAL); |
| } |
| |
| static int amv_write_packet(AVFormatContext *s, AVPacket *pkt) |
| { |
| AMVContext *amv = s->priv_data; |
| int ret; |
| |
| /* Add a dummy frame if we've received two of the same index. */ |
| if ((ret = amv_pad(s, pkt)) < 0) |
| return ret; |
| |
| if ((ret = amv_write_packet_internal(s, pkt)) < 0) |
| return ret; |
| |
| if (pkt->stream_index == AMV_STREAM_VIDEO) { |
| /* Save the last packet for padding. */ |
| av_packet_unref(&amv->vpad); |
| if ((ret = av_packet_ref(&amv->vpad, pkt)) < 0) |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| static int amv_write_trailer(AVFormatContext *s) |
| { |
| AMVContext *amv = s->priv_data; |
| AVStream *vst = s->streams[AMV_STREAM_VIDEO]; |
| AVStream *ast = s->streams[AMV_STREAM_AUDIO]; |
| int64_t maxpts, ret; |
| int hh, mm, ss; |
| |
| /* Pad-out one last audio frame if needed. */ |
| if (amv->last_stream == AMV_STREAM_VIDEO) { |
| if ((ret = amv_write_packet_internal(s, &amv->apad)) < 0) |
| return ret; |
| } |
| |
| amv_end_tag(s->pb, amv->movi_list); |
| amv_end_tag(s->pb, amv->riff_start); |
| |
| ffio_wfourcc(s->pb, "AMV_"); |
| ffio_wfourcc(s->pb, "END_"); |
| |
| if ((ret = avio_seek(s->pb, amv->offset_duration, SEEK_SET)) < 0) |
| return ret; |
| |
| /* Go back and write the duration. */ |
| maxpts = FFMAX( |
| av_rescale_q(amv->lastpts[AMV_STREAM_VIDEO], vst->time_base, AV_TIME_BASE_Q), |
| av_rescale_q(amv->lastpts[AMV_STREAM_AUDIO], ast->time_base, AV_TIME_BASE_Q) |
| ); |
| |
| ss = maxpts / AV_TIME_BASE; |
| mm = ss / 60; |
| hh = mm / 60; |
| ss %= 60; |
| mm %= 60; |
| |
| avio_w8(s->pb, ss); |
| avio_w8(s->pb, mm); |
| avio_wl16(s->pb, hh); |
| return 0; |
| } |
| |
| AVOutputFormat ff_amv_muxer = { |
| .name = "amv", |
| .long_name = NULL_IF_CONFIG_SMALL("AMV"), |
| .mime_type = "video/amv", |
| .extensions = "amv", |
| .priv_data_size = sizeof(AMVContext), |
| .audio_codec = AV_CODEC_ID_ADPCM_IMA_AMV, |
| .video_codec = AV_CODEC_ID_AMV, |
| .init = amv_init, |
| .deinit = amv_deinit, |
| .write_header = amv_write_header, |
| .write_packet = amv_write_packet, |
| .write_trailer = amv_write_trailer, |
| }; |